قديم 06-Nov-2009, 02:14 AM   #1
Abdulrahman Alswaid


مدير عام موقع و منتدى الوراثة الطبية
 
الصورة الرمزية Abdulrahman Alswaid
مورث قمة التميز
رقـم العضويــة: 1
تاريخ التسجيل: Apr 2002
مــكان الإقامـة: السعودية
المشـــاركـات: 19,306
مــرات الشكر: 711
نقـاط الترشيح: 5
نقـــاط الخبـرة: 2538
...

افتراضي متلازمة جوبرت:مواضيع مهمة بالانجليزية و تحتاج ترجمة

السلام عليكم

هذه دعوة للتعاون فيما بينكم في جمع و ترجمة و تأليف مواضيع باللغة العربية
لمساعدة الاسر و مساعدتكم في تبادل المعلومات عن متلازمة جوبرت

هذه مواضيع انجليزية مناسبة من مؤسسة متلازمة جوبرت

PHYSICAL THERAPY FOR THE CHILD WITH JOUBERT SYNDROME
As noted at the past conferences, information regarding Joubert Syndrome has broadened in recent years. Those
diagnosed with Joubert Syndrome present with signs and symptoms that help identify this special population of children
and adults. The signs and symptoms that are of particular importance to the physical therapist include bin are not limited
to ataxia, generalized hypotonia, respiratory irregularities, developmental delay, tactile defensiveness, dysgord and
equilibrium dysfunction.
It is important to recognize the atypical alignment presented in all positions in order to formulate a program. It is true in all
instances that the strong get stronger and the weak get weaker in reference to muscles that are over or under worked. It
is therefore very important that positioning that affords biomechanically appropriate alignment is provided to the child.
Attaining biomechanically appropriate alignment early in treatment reduces intervention problems later on.
Ranges of motion must be maintained to allow efficient muscular control across the joints. Strengthening of
atypically elongated muscles and stretching of shortened muscles and soft tissues is necessary to gain in
neuromuscular. An individualized program; to strengthen the child proximally provides him with a basis
from which automatic postural reactions of righting, protective extension of upper extremities, equilibrium can emerge.
POSITIONING:
Prone:
1. Place a small roll under the axilla of the child or place on appropriate sized wedge. Rolled towels may also be
necessary laterally to the hips to prevent the legs from aligning in abduction with external rotation. Weight bearing on
forearms is encouraged. A mirror or items of interest are to be placed for visual stimulation. If child cannot elevate
head, assist and gently remove some assistance to encourage child to extend neck.
2. The above prone position can also be enjoyed with the placement of the child across parent's lap. I have periodically
used swaddling or a wide elastic band in figure S configuration to maintain appropriate alignment of legs while
working with upper extremities and head. It is noted that the buttocks muscles contract if alignment through hips is
more true to their mechanical advantage.
Supine:
1. Elevate the head on a small pillow or wedge. Place small towels under the shoulders to prevent the arms from failing
into surrender posture. A rolled towel under the knees is also recommended. Use of high top sneakers or non
articulated AFO's is recommended if the child habitually strongly points the toes, (remember the weak get weaker ie.
the muscles that pull the feet upward and the strong get stronger- ie. the muscles the point the toes). Use of AFO's
in this instance is for appropriate anatomical alignment and not for ambulation early in early in development.
Correcting the signs early may reduce the symptoms later and reduce or eliminate amount of bracing needed in the
future. Place items of interest suspended across child to encourage batting and activating toys.
Side lying:
1. Side lying is generally a position that is not enjoyed, but it should be encouraged to allow the child to engage hands at
midline and play with toys that require two hands to manipulate. The head is placed on a small wedge or pillow and a
small towel can be placed between the legs to keep hips in appropriate alignment.
Sitting:
1. Provide the child with a seat that allows him postural security when expecting eye/'hand coordination
and fine motor skills. It is too much to expect him to work on keeping his postural alignment biomechanically appropriate
while performing fine motor projects. Place yourself in the position having to sit stop a top a telephone pole. Could you do
your very best handwriting? Many parents reject postural restraints like lap belts and harnesses because the child is "not
working on his balance." There is a time and place for everything. These children have severe difficulty with proximal
stability and initially cannot provide anchor to their posture.
2. The chair must fit in depth, width and height. It is not appropriate to have the child seated in a standard chair
anticipating his growth during the school year will eventually allow a chair that fits.
3. Do not consistently pull the child to sit if head control is poor as this procedure engenders the persistence of head lag.
As the child strengthens, add to the difficulty of the task by increasing the arc of movement and finally progress to pulling
to sit from supine.
13
Quadruped:
1. The quadruped position is very difficult to maintain; you may need to figure the lower extremities to give one more
controlling "hand" to gain appropriate alignment of femurs to hips. Initially head control may be so poor that the child
may begin to "creep" with head sliding on the floor.
Stance/Gait:
1. Prone standers and wheeled walkers are of value to developmental progression.
2. A program facilitation of coordination and balance reactions in all positions is highly recommended and the need
continues long after the child becomes ambulatory. At issue is the safety of the child as counteracting balance reactions to
sudden challenges are often slow and performed with care.
Intervention provided by a pediatric physical therapist may include the following techniques which vary according to age
and degree of disability.
1. Evaluation
2. Therapeutic exercises
3. Neurodevelopment program
4. Kinetic mobility
5. Myofascial release techniques
6. ROM's
7. Facilitation of gross motor skills
8. Ongoing assessments
The therapeutic program includes but is not limited to:
1. Normalization of tone through positioning, weight bearing, tactile input, etc.
2. Enhancement of gross motor skills in a developmental progression
3. Facilitation of basic automatic postural reactions, (protective extension of upper extremities, equilibrium reactions,
righting reactions) as a foundation for normal postural growth
4. Enhancement of kinesthetic and proprioceptive awareness
5. General strengthening program
6. Inhibition of persistent primitive postural reflexes
7. Maintenance/improvement of ROM'S as indicated
Ongoing communication with your physical therapist regarding positioning and home programs is necessary. The physical
therapist working with your child should be a Developmental Pediatric Physical Therapist with neuro background.
14
SPEECH-LANGUAGE THERAPY FOR THE CHILD WITH JOUBERT SYNDROME
Diane Lewis, MA, CCC/SLP
All the children whom I have met with Joubert Syndrome have presented delays in one or more areas that make up "communication."
The skills required to becoming an effective communicator that Joubert Syndrome can affect are:
1) Receptive language/concept development
2) Auditory processing
3) Feeding/oral-motor skills
4) Speech articulation
5) Grammar
6) Social skills
The rest of this papa- will very briefly describe each of these areas and how a parent can work with a
Speech-Language Pathologist to strengthen these skills. The family should first contact the American
Speech-Language and Hearing Association in Rockville, MD and request a list of Speech-Language Pathologists (SLP) in your area
that have a Certificate of Clinical Competence (CCC). Then the family should interview whomever is on the list to see if they posess the
skills to work on these six areas and/or have ever worked with a child with Joubert Syndrome.
Upon meeting your child, the SLP should observe you play/communicate and feed your child. After that she may choose to administer
standardized tests as indicated.
1) Receptive Language/Concept Development:
These skills include understanding a wide range of nouns, verbs, prepositions and adjectives. Many of these are learned through
experience with the actual object while at home with the family, ie. the family could do an activity that reinforces animal names by
playing with a barn set, sing Old McDonald, or present toys that make the sounds.
2) Auditory Processing:
These skills include receiving information through the ear which is then transferred to the auditory cortex in the left temporal lobe of the
brain, ie. responding to his/her name, a one step direction, comprehension etc. First you should have your child tested by a certified
Tomatis or Berard Auditory Training practioner to see if your child has any hypersensitivities to sound. If so, these should be treated so
your child will be more able to attend to auditory information. After that, your therapist will tell you where to begin on the hierarchy of
teaching your child how to listen and make sense of what he/she hears. The Fast ForWord computer program is available for
decreasing temporal sequencing which makes it easier for the older child to process language and Seam how So read.
3) Feeding/Oral -Motor:
Feeding Oral motor skills are always negatively impacted upon in the child with Joubert Syndrome since all of these children have
atypical sensory-motor processing throughout the face/mouth. The primary symptom is hypotonia or "floppy" muscles. Frequently
the child with Joubert Syndrome has delayed feeding skills and drooling. Some of these children are hyper or hyposensitive to touch,
be it food, the spoon or the cup.
4) Speech Articulation:
The atypical sensory-motor skills throughout the face/mouth areas will result in difficulties acquiring intelligible speech. The SLP should
combine her work on oral-motor/feeding and speech since there is overlap in the use of the musculature for all these skills. If there is a
"gap" between what the child comprehends/cognition and what she is able to communicate intelligibly, the SLP should provide
alternative expressive communication systems while the child works on developing more intelligible speech, ie. sign language, picture
boards, computers, voice cutout devices, etc.
5) Grammar:
Grammar is the child's ability to combine words into sentences and to use correct endings, ie. plural, possessive, past and future
tenses, etc. Many children with Joubert Syndrome have difficulty developing these these skills due to both oral-motor/speech delays as
well as auditory processing delays. The SLP will frequently combine a variety of strategies to develop grammatical skills, ie. picture
cues, toys, etc.
6) Social Skills:
In order for the previous five parts of communication to become functional, the child must learn certain basic social functions, ie. greet,
request, respond, comment, etc. The child must learn that other people are an important part of their world and must be motivated to

join in with them. The SLP can demonstrate to the family of the child with Joubert Syndrome how to engage their child in even the most
basic activities, ie. peek-a-boo and how to close "the circles of communication" using the most intelligible abstract means available to
her at the moment, ie. gestures, speech, sign language, etc.
Diane Lewis is the Speech and Language Pathologist for our Foundation. If you would like more extensive information you may contact
her at:
Diane Lewis, MA, CCC
Communication Enrichment Services
5109 Battery Lane
Bethesda, MD, 20814
301-652-2220 (301) 652-9555 (fax)
email: dianelewisces@aol.com






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[/CENTER]
عبدالرحمن السويد
استشاري طب الاطفال و الامراض الوراثية
http://www.werathah.com/
تنبيه : إن المعلومات الطبية والعلاجية الواردة في هذا الموقع قد روعي فيها الدقة والتوثيق العلمي قدر الإمكان،
وذلك بغرض المعرفة والإطلاع فقط وينصح باستشارة الطبيب المختص عند الحاجة

Abdulrahman Alswaid غير متواجد حالياً   رد مع اقتباس
قديم 06-Nov-2009, 02:17 AM   #2
Abdulrahman Alswaid


مدير عام موقع و منتدى الوراثة الطبية
 
الصورة الرمزية Abdulrahman Alswaid
مورث قمة التميز
رقـم العضويــة: 1
تاريخ التسجيل: Apr 2002
مــكان الإقامـة: السعودية
المشـــاركـات: 19,306
مــرات الشكر: 711
نقـاط الترشيح: 5
نقـــاط الخبـرة: 2538
...

افتراضي

ORAL STIMULATION EXCERCISES
1. Stroke lips from center to top lip to corner of mouth. Do one side, then the other.
2. Gently stimulate lips, tongue, or alveolar ridge with a soft regular or electric toothbrush.
3. Rub lips with vaseline or flavored lip gloss/salve.
4. Massage lips or checks with facial sponge or hands.
5. Make funny faces in mirror.
6. Hold a small object between the lips. Try gently to pull it out.
7. Paint face with face paints.
8. Copy oral movements and vocalization ie: “baa…ba…baa”, “la…la… la…”, “me… me… me…”.
Use exaggerated movements.
9. Lick lollipop, ice cream etc. to exercise tongue.
10. Place food around outside of lips, ie: pudding and encourage child to lick it off.
11. Encourage inspection of child’s mouth and parent’s mouth. Name parts.
Updated 11-2002




OCCUPATIONAL THERAPY FOR THE CHILD WITH JOUBERT SYNDROME
Children with Joubert Syndrome frequently have motor delays and processing disorders which affect their ability to react
and relate to their environment. Research suggests that some of these delays are the results of anomalies in the
cerebellum (lack of vermis) which results in changes with muscle tone, effects on balance, and difficulties in processing
sensory information. These combinations have a global effect influencing gross-motor, fine-motor, perceptual-motor, self
care and daily living skills.
Listed below are observations and some strategies to address the above issues:
1) SENSORY PROCESSING: An occupational therapist trained in sensory processing/sensory integration is best able to
assist with assessing this area. Nearly all children with Joubert Syndrome will have sensory processing disorders. This
includes how we use and interpret our senses such as hearing, seeing, touching, and tasting. It also includes
information from the muscles and joints (proprioception), and information from movement and gravity (vestibular input).
Following a “Sensory Diet" that is giving a variety of input (tactile, proprioceptive and vestibular) on a regular basis
throughout the day, to your child will assist the brain to be in a more ready state to learn. Some techniques such as
deep pressure, joint compression, trampoline play, use of a weighted vest, ankle or wrist weights or the use of rotational
equipment are just some techniques that may be incorporated into a child's routine as part of a "sensory diet". Some
individuals may participate in a technique known as the "Willbarger Protocol”, ie. being brushed with a corn brush
followed by joint compression. Any sensory diet or specific sensory technique should first be evaluated by an
occupational therapist trained in this area. The success of a "sensory diet" is via team work of the parents, all
therapists, (P.T., O.T., speech therapist, etc.) and school staff. Sensory diets to be successful do not occur in a vacuum
and should continue throughout the day with the support of all persons involved.
2) GROSS & FINE MOTOR SKILLS: Children with Joubert syndrome tend to have low muscle
tone as well as difficulties with balance. It has been this workers experience that motor skills do progress in gradual
progression. It will not be unusual for a child with Joubert Syndrome to walk at the age of five or six years of age.
Neurodevelopmental techniques are effective especially when incorporated with a sensory diet. The use of ankle/foot
orthoses (braces) or orthotics may also be beneficial and this matter should be referred to a physician trained in
orthopedics or a physical therapist for evaluation- Once children are in school, specialized or adapted chairs may be
appropriate to ensure the child has adequate positioning (ie. feet on floor, adequate support at the trunk, etc.) A slanted
desk top will provide added stability for the arms during writing tasks and will also promote proper posture.
3) ORAL-MOTOR AND FEEDING SKILLS: Most children with Joubert Syndrome have feeding delays and
may have difficulties with sucking and swallowing due to low tone in the face. This therapist has had some
success with the use of a vibrator to the facial muscles to increase muscle tame especially prior to feedings or meals.
Caution needs to be observed and the parents should consult with an occupational therapist or speech therapist as many
of the children are hyper-sensitive to touch. If frequent hand-to-mouth behaviors are observed, oral stimulation should be
incorporated into the sensory diet
4) SELF-CARE/ACTIVITIES OF DAILY LIVING: When teaching self-care skills this worker has had success with
backward chaining techniques, that is teaching the last step of a task first For example, when teaching a child to pull up
their pants, the initial step is to pull the pants just over the hip as the first step, after success is noted the pants are pulled
down a little further and then pulled up again. This technique can be used with a variety of self-care skills particularly in
the dressing area. In regards to other life skills, as much as possible, children with Joubert Syndrome should be exposed
to similar activities as their siblings and peers with adaptations being modified as needed. For example when teaching to
ride a tricycle or bike, modified foot dates with straps have been successful.
When requesting occupational therapy services parents should first determine that a therapist is either registered a
licensed and then begin to seek a therapist who has training in neurodevolopmental techniques (NDT) and sensory
processing or sensory integration (SI). Some therapists will have specific training in the above treatment and will be
known as NDT or SI certified. To find a therapist certified in sensory integration in your area or would like written
materials, call Sensory Integration International at 310-787-8805 or http://www.sensoryint.com/





SENSORY PROCESSING AND HOW IT AFFECTS LEARNING AND BEHAVIOR
by Mary Ann Trott, MA
Everything we do is based, to some extent, on our ability to process sensory information. The information we
receive from seeing, hearing, touching, tasting and smelling as well as the information we receive from our
muscles, tendons and joints (proprioception) and information about gravity (vestibular) is sensory information.
That information is received by the eyes, ears, skin etc. and is interpreted by the brain. The brain must then be
able to organize and use that information. The brain's use of sensory information is what allows us to
understand and react to our environment and to learn from that environment. Our brains also use sensory
information to modulate oar alertness. This modulation allows us to maintain an appropriate level of alertness
to meet the demands of each day. For example, we first wake up, men we need to pay attention while we drive
to work, we need to be calm enough and alert enough to do all that is required of us during the day and finally
we need to calm
ourselves to fall asleep.
Some children, particularly those who have neurological impairments (such as Joubert Syndrome) do not
process sensory information in a way that is comparable to the majority of their peers. These differences or
difficulties may affect the way children behave and learn. Some children may be very fearful or cry easily.
Others may be very picky about things that come in contact with their skin. Some children are unwilling to
participate in movement activities, others may be over active. They may have difficulty in reading, writing
legibly, copying from the board or understanding what is said. Some children seem to be driven to go through
certain "rituals" such as rocking, wrapping themselves up very tightly or wearing certain clothing items. It may
appear that these children are very controlling and aggressive or very passive. It is important to understand
that these are not learned behaviors but neurological responses that an individual is not able to control.
An occupational therapist who has neurodevolopmental or sensory processing/integration training is the
professional who is best able to determine if a child has a sensory processing disorder. An occupational
therapist can also provide treatment. Teachers do not often have information about sensory processing and it
is important for them to understand that certain behaviors and/or inabilities are related to a neurological
process rather than a behavioral one. This understanding will also help to determine how best to deal with and
treat the problem.
For further information and practical suggestions for parents and teachers refer to SenseAbilities:
Understanding Sensory Integration
This is available from:
Therapy Skill Builders, a division of Psychological Corporation
555 Academic Court
San Antonio, TX. 7S2&4-2498
l-SOO-228-0752
Mary Ann Trott is a co-author of SenseAbilities:Understanding Sensory Integration. She is also our special
education advisor for the Joubert Syndrome Foundation. She can be contacted for questions at:
Mary Ann Trott, MA
1621 Richmond, NE
Albuquerque, NM 87106
505-298-6752 ext 3427 (work)
505-266-2632 (home) Prefers calls at home
e-mail: wmtrott@flash.net or trott@aps.edu


CLASSROOM SUGGESTIONS
Many children, even those who do not have sensory processing disorders, will benefit from some of
the strategies that are suggested for the children who do have sensory processing disorders. Listed
below arc some things you can try and probably some things you do already. If you decide to
implement some of these suggestions, try them one at a time. Chances are me first few days will be
difficult but when the novelty wears off, you may see some positive changes. Stick with each thing for
at least two weeks and add new ideas slowly.
* Allow children to choose to work while standing, sitting or tying on the floor or in different seated
positions.
* If children are not able to finish work prior to recess, require them to complete a vigorous movement
activity, (running a lap, going hand over hand across some bars, climbing up and down the monkey
bars 5 times, etc.) and then return to work. This will help increase production much more than
requiring them to miss recess. Don't you allow yourself a break when you've had a hard time
concentrating?
* During instruction, use tactile and movement experiences as well as auditory and visual
experiences.
* Base requirements for classroom behavior on the following questions: Is it safe? Is it respectful of
myself and others? Is it respectful of property? (NeiII,1991)
* Have one or two quiet areas in the classroom (maybe with some pillows, blankets and/or stuffed
toys if appropriate) that children can choose for working or taking a break.
* Include movement in practice activities and in instruction as much as possible.
* Encourage children who have a hard time with writing to practice writing skills on a chalkboard.
* Some children will concentrate better and be less distracted if they can drew or play with small hand
toys or wad of clay during listening activities.
* Ask children to bring a sports bottle with a straw to school. These can then be filled with water and
used for sipping throughout the day.
* Have on hand a large stack of books or some other heavy items mat will periodically "need" to be
moved.
* Allow children an opportunity to move quietly around the classroom when direct instruction is not in
progress.
* Some children will benefit from listening to music through headphones while working.
* Have a goodie bowl with gum and/or hard candy for children to chew or suck on as needed.
* Use natural lighting if possible.
Mary Ann Trott




THE EYE AND VISION IN THE CHILD WITH JOUBERT SYNDROME
by Latif Hamed, MD

Patients with Joubert Syndrome may display a variety of eye or vision abnormalities. Not all of these abnormalities are
present in every patient. These abnormalities may arise due to lesions in the nervous system or the eye itself and may
affect the vision, the eye movements, the ocular alignment or the structures surrounding the eye such as the eyelids.
None of these conditions by themselves are unique to Joubert syndrome. Instead, it is the combination of many of these
findings in one patient that leads to suspecting that Joubert Syndrome is a likely diagnosis. I will provide a glossary of the
most common eye findings in patients with Joubert Syndrome along with a brief explanation of each.
Strabismus: This is a generic term that simply means eye misalignment. The eyes can be deviated inwardly, outwardly
or vertically. The deviation may be a result of abnormal brain signals, damage to the nerves that feed the eye muscles, or
abnormalities in the eye muscle themselves such as in ocular fibrosis where the eye muscles are abnormal and the
muscle tissue is replaced with scar tissue. The amount and direction or misalignment can be measured with prisms. If the
situation warrants, strabismus can be corrected with an operation on the eye muscles to restore the balance among (he
vectors of forces created the various muscles.
Skew Deviation: This is a type of strabismus wherein the eyes are vertically misaligned (one eye higher than the other).
It is associated with abnormalities in the brainstem or the cerebellum. Nystagmus (dancing eyes ): This is abnormal toand
fro oscillation of the eyes that is rhythmic and repetitive. It is associated with abnormalities in the brainstem or
cerebellum or with poor vision due to abnormalities in either the retina or the optic nerves. Different types of nystagmus
are classified on the basis of the direction, amplitude, and frequency of the eye oscillation. Therefore you will hear such
terms as pendular torsional nystagmus, see-saw nystagmus, jerk nystagmus, etc.
Congenital Retinal Dystrophy: With this condition, the retina which is analogous to the film in the camera, is abnormal
which causes poor vision that cannot be corrected with glasses. The appearance of the retina is rather mottled with fine
dark pigment spots scarred throughout the retina. The retina is not functioning properly, and the extent of the dysfunction
can be determined by using a test called electroretinogram which assess the function of the cells that make up the retina
such as the rods and the cones. Currently, this retinal disorder has no treatment, but like many similar disorders, it is one
where that when genetic therapy becomes available will make a great impact.
Colobomas: These are defects in the inner coats of the eyeball caused by failure of complete closure of a fissure in the
embryonic eye. Part of the fissure remains open. That opening corresponds to a defect called coloboma where the retina
and choroid coats are absent and the ophthalmologist examine the inside of the eye will see the coloboma as a white
island (only white sclera is present) in a sea of pink normal eye coats where all three layers (retina, choroid and sclera)
are present. If the coloboma occupies the area of the optic nerve or key areas in the retina, the vision can be significantly
affected. Small peripheral colobomas are often visually inconsequential.
Ocular Motor Apraxia: Some children do not have the ability to willfully initiate a quick eye movement such as switching
gaze to an object on the side. To compensate for this problem which is caused by a brain abnormality, these children use
their head to drive their eyes. They display what is called head thrusts where the head is quickly moved to one side then
returned.
Ptosis: This is the drooping of one or both eyelids which if severe can be surgically improved.
Optic Nerve Hypoplasia; This means underdevelopment of the optic nerve which appears considerably smaller in cross
section when visualized by the examiner through the pupil. The normal optic nerve contains 1.2 million fibers during the
development of the embryo. If severe, optic nerve hypoplasia can lead to significant visual impairment which cannot be
corrected with glasses.
Cortkal Bimdness: I do not like this term and prefer instead the term cortical visual impairment because most such
patients are not completely blind. This condition is caused by damage to the nerve pathways in the brain that are
responsible for conducting and processing visual information. The visual impairment can range from mild to severe. Many
children have what is called mixed vision loss, which means that some of the vision loss is caused is damage to the brain
(cortical visual impairment) and some of it is caused by abnormalities outside the brain such as in the optic nerves, the
retina or other structures.
As you know, Joubert Syndrome is rare, and many specialists do not have practical experience with it. The
specialist most likely to be familiar with the eye manifestations in Joubert Syndrome is either a pediatric
ophthalmologist or a neuro-ophthalmologist. Ideally one who is trained in both fields would have the best insight but this
varies from one specialist to another depending upon the level of knowledge, experience and comfort level examining
children with neurological disorders. I am not a big believer in vision training for children with this disorder if it means

enrollment in specific visual training for programs with specific eye exercises, etc. I think what works is paying close
attention to your child as a whole, having meaningful interaction with the child as any loving parents would, and making
sure mat you do not miss the forest for the tress. When deciding how to approach the treatment of any of the disorders
found in Joubert Syndrome, the over-arching question ought to be: How will this treatment affect the well-being and the
quality of life of my child as a human being over his or her life time, rather than simply how would the vision be affected by
the treatment.
Questions can be directed to:
Latif Hamed, MD, FACS
Florida Eye Specialist Institute
3233 SW 33rd Road, Suite 202
Ocala, FL 34474
352-237-0090
352-237-0052 (fax)






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ارجو مساعدتنا في نشر رقم الاشتراك بالواتس اب... شكراً

:: صفحات التواصل الاجتماعي لموقع الوراثة الطبية ::

----تويتر------الفيسبوك






[/CENTER]
عبدالرحمن السويد
استشاري طب الاطفال و الامراض الوراثية
http://www.werathah.com/
تنبيه : إن المعلومات الطبية والعلاجية الواردة في هذا الموقع قد روعي فيها الدقة والتوثيق العلمي قدر الإمكان،
وذلك بغرض المعرفة والإطلاع فقط وينصح باستشارة الطبيب المختص عند الحاجة

Abdulrahman Alswaid غير متواجد حالياً   رد مع اقتباس
قديم 06-Nov-2009, 02:21 AM   #3
Abdulrahman Alswaid


مدير عام موقع و منتدى الوراثة الطبية
 
الصورة الرمزية Abdulrahman Alswaid
مورث قمة التميز
رقـم العضويــة: 1
تاريخ التسجيل: Apr 2002
مــكان الإقامـة: السعودية
المشـــاركـات: 19,306
مــرات الشكر: 711
نقـاط الترشيح: 5
نقـــاط الخبـرة: 2538
...

افتراضي

A spectrum of Joubert syndrome?
When splitting occurs, scientists often bring in new conditions that have different, unfamiliar names, and ask if
they should also be included in the subdivision process. That’s why many of you heard terms such as “Arima,” “Dekaban,”
“Senior-Loken,” “Varadi,” and “COACH” syndrome for the first time. These names may not seem helpful for families at
first, and the medical practice of using proper names or abbreviations to describe conditions is indeed confusing, even for
doctors. However, these names may be useful to us scientists in looking through the medical literature, because these
terms can help us learn about children who have been described in the past and in this way, we can share information
more effectively with each other. These labels may also reflect the way specialists in different medical fields emphasize
specific clinical features in the patients they see in their practice, and the shared nomenclature among a group of
specialists is very valuable for their communication.
I think one of the most useful outcomes of the recent Joubert symposium was the agreement among researchers
(yes, sometimes we CAN agree!) that what we and you have termed “Joubert syndrome” represents a spectrum of
disorders that have some features in common but other features that vary. This may sound obvious to many of you who
have been attending these workshops for years, because you know that your child is similar to some of the other children
26
with Joubert syndrome, but is also very different from other children. How we understand and categorize those similarities
and differences is the real challenge. One area of consensus in the scientific meeting was that the fundamental feature of
the “molar tooth sign” visualized on specific views of an MRI scan is a critical step in making a diagnosis of Joubert
syndrome. There are also aspects to the brain anatomy other than the molar tooth sign (for example, degree of cerebellar
vermis dysplasia) that need to be considered when radiologists grade the malformations. Other features, such as kidney
problems, eye or retinal changes, and liver problems, are likely to be specific to certain subgroups of Joubert syndrome. It
should be remembered that children with other rare brain malformations that are not “classic” examples of Joubert
syndrome could have a molar tooth sign, which is another potential source of confusion. So far, there have been no
studies to determine how all of the disorders above overlap in terms of MRI findings.
Labeling the different conditions
Nobody likes labels, but they provide useful information. How, then, should we describe the different subtypes of
Joubert syndrome? Adding difficult eponyms such as Arima syndrome or Senior-Loken syndrome isn’t that helpful for
parents and most physicians. Borrowing from the genetics literature, the most useful terminology might be to use
numbers, for example “Joubert syndrome-type 1” or “Joubert syndrome-type 2.” This would require defining the specific
features of JS-1 and agreeing upon them. Alternatively, since we know that more than one gene is likely to cause Joubert
syndrome (see accompanying article), we may use “JS-1” to describe children who have a genetic change in one specific
gene, and “JS-2” to describe those who have a change in the second gene, and so on. As you can see, this logical form of
classification requires the discovery of the Joubert syndrome genes, a difficult task that we are actively pursuing.
The importance of an accurate diagnosis: different genes, different outcomes?
You might wonder why the subcategories are so important, if it’s all just Joubert syndrome anyway. This is why it
is crucial: A child with JS-2, for example, may be more likely to develop kidney problems than a child with JS-3. If we
know that a specific type of genetic change is never associated with kidney problems, we can tell a family that the risks of
kidney failure are almost zero (geneticists never say “never”!). If I were a parent, I would want to know this information. An
accurate diagnosis, whatever nomenclature is agreed upon, allows for more accurate information so that parents,
physicians, and therapists can provide the best possible care for each individual child. This is also why genetic studies
and a national Registry are so important in Joubert syndrome and why your participation is crucial. The more families who
participate in providing clinical information and donating blood samples, the more likely we will be to identify the genes
that cause this spectrum of conditions, and the better diagnostic and medical information we can give you. In my
experience as a geneticist, many, many conditions have different clinical profiles depending on which gene is causative,
although they may look confusingly similar before the genes are discovered. Only with the discovery of causative genes
do some of these differences become understandable. Although we can’t guarantee that this will be the case for Joubert
syndrome, there is a good chance that there will be different symptoms and medical problems for different types of
Joubert syndrome. However, there will always be many common medical problems for all Joubert patients, which makes it
sensible to retain a common support group, i.e., “strength in numbers.”
A dynamic partnership between parents and medical professionals is essential
As a geneticist, I spend a lot of time with families trying to give them the most accurate and specific diagnostic
information available. But I recognize that the field of genetics is constantly changing, and new information is always being
discovered. Even when I make a specific diagnosis for a child and am able to provide a genetic test that confirms this
diagnosis, I always tell parents to stay in touch periodically, and I generally recommend a follow up appointment in 1, 3, or
5 years. This is to provide new information that we hope will be helpful for them. As research unfolds, I anticipate an
explosion of new information about Joubert syndrome in the next few years.
Here’s where parents can help. The new information and medical literature that we rely on for information about
rare conditions such as Joubert syndrome comes from only one ultimate source: you! In addition to blood samples to help
with genetic linkage studies, we need your input about how your child is doing, what observations you have made, copies
of clinical reports, and the results of a variety of tests such as renal ultrasounds in order to understand the similarities and
differences between children with Joubert syndrome. This is why your participation in a national Registry that Dr. Maria is
organizing at the University of Missouri in collaboration with us and others is so vital. This is why we keep asking you to
answer questions about your child over and over again. The questions we ask today are much more sophisticated than
the questions we asked even 5 years ago! So please help in the partnership to understand this condition by sharing your
wisdom about your children.
Some important conclusions from the meeting
But back to the meeting: in spite of the confusion, was there any important information the scientific and medical
community provided for parents? Absolutely. Since we can’t yet subclassify children with Joubert syndrome on genetic
and/or clinical features just yet, we have to be cautious about long-term risks for complications such as vision, kidney, or
liver problems. In collaboration with the group of investigators present in New Orleans, we are currently developing
“consensus recommendations” for children with Joubert syndrome. Recommendations for MRI testing, vision, kidney and
liver function, developmental and behavioral testing will be published in a forthcoming Newsletter.
Final thoughts: A diagnosis doesn’t change who your child is
In my genetics practice, sometimes I have to tell parents that the diagnosis they were
given years ago based on incomplete information (or the best information available at the time)
isn’t the best diagnosis for their child. This can be very difficult for many parents, because as
much as we hate labels, they also provide a handle to understanding, an identity, and the support
of others who share the same challenges. I always try to provide information on support groups
for such parents. More than once, I have told parents that even if a particular diagnosis isn’t the
“best fit” for their child, if they derive benefit from being in a particular support group, by all
means, keep participating!! You have a dynamic, proactive, and compassionate group of
founding members and current officers in the Joubert Syndrome Foundation, and I hope you
continue your involvement with this wonderful group, no matter what subtype of Joubert
syndrome your child ultimately has. As you all know, a specific diagnostic label doesn’t change
anything about who your child is. And all of the children (and adults) I met at the Joubert
syndrome symposium are special, unique human beings.
Melissa A. Parisi, MD, PhD






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----تويتر------الفيسبوك






[/CENTER]
عبدالرحمن السويد
استشاري طب الاطفال و الامراض الوراثية
http://www.werathah.com/
تنبيه : إن المعلومات الطبية والعلاجية الواردة في هذا الموقع قد روعي فيها الدقة والتوثيق العلمي قدر الإمكان،
وذلك بغرض المعرفة والإطلاع فقط وينصح باستشارة الطبيب المختص عند الحاجة

Abdulrahman Alswaid غير متواجد حالياً   رد مع اقتباس
قديم 06-Nov-2009, 02:24 AM   #4
Abdulrahman Alswaid


مدير عام موقع و منتدى الوراثة الطبية
 
الصورة الرمزية Abdulrahman Alswaid
مورث قمة التميز
رقـم العضويــة: 1
تاريخ التسجيل: Apr 2002
مــكان الإقامـة: السعودية
المشـــاركـات: 19,306
مــرات الشكر: 711
نقـاط الترشيح: 5
نقـــاط الخبـرة: 2538
...

افتراضي

GENETICS FOR THE FAMILY
JOUBERT SYNDROME
Phillip Chance, MD, FACMG
1) Please discuss the how the research for the gene is being carried out?
The gene (or '"A" gene) for Joubert Syndrome has not been found. This means that we have not found a chromosomal
location for it yet. Dr. Koenig (in Strasbourg, France) has carried out large scale genetic linkage studies (beyond those by
myself and Joan Pellegrino done a Children's Hospital of Philadelphia and which you already know about) using several
families in which 2 or more children are affected with Joubert syndrome and did not find linkage to a particular
chromosome. His model or method assumed that there is one gene for Joubert and that all families under study have a
mutation in the same gene. This is probably not the case and I'm sure that he will say a lot more about it at the meeting in
Montreal (1998). I suspect that Joubert may in reality be several different genetically distinct disorders which on clinical
grounds appear to resemble one another (so closely that clinically we cannot tell them apart). This is known as "genetic
heterogeneity" and it is seen frequently in genetic diseases. Until the gene is localized to a particular chromosomal region
and ultimately identified, we have no genetic tests to predict who is a carrier and who is affected, (e.g. for prenatal
diagnosis purposes.)
2) Explain autosomal recessive inheritance. Explain consinguaneous relationship.
Autosomal recessive inheritance implies that when paired with a normal gene (and all autosomal genes are present in
pairs, that is we received one copy from each parent), a mutant recessive gene doss not express itself, that is, it does not
lead to expression of a disease. Therefore; a child who has an autosomal recessive disorder (e.g. Joubert Syndrome) has
inherited a mutant, silent gene from each parent. The parents themselves are only gene "carriers" and such do not
manifest the disorder because it is "recessive." Therefore, recessive disorders require me presence of two abnormal
genes, one abnormal copy having been inherited from each parent.
Consanquinity means a mating between two blood relatives that is two persons who share common genetic ancestry.
Cousin/cousin matings are probably the most frequently encountered- It usually is not a problem unless a recessive
genetic disorder is present in the family. Because consanguineous parents would be expected to have some genes in
common, it is conceivable that they may share a mutant recessive gene. If so, they would be at increased risk for having
a child affected with whatever autosomal recessive disorder is present in the family.
3) What is the prevalence of Joubert Syndrome in the USA?
I don't know the prevalence in the USA. I'm sure that it is rare. Probably no more frequent than 1 in 50,000 births.
4) What are the chances that my other children will be carriers?
For unaffected siblings of a child with Joubert, their risk for being carriers is two-thirds.
5) If my unaffected child is a carrier, what are the chances that he/she will have a child with this syndrome?
The risk for normal person with a sibling with Joubert having an affected child would be two-thirds multiplied by the
estimated population rate or carriers (a number that we do not precisely know-but given that Joubert is rare, this has to be
a small number). Therefore the risk for a normal person under such circumstances would be very low.
6) What are the chances that my siblings are carriers?
Same as question 4
7) If my sibling is a carrier, what are the chances that he/she will have a child with this syndrome?
Same as question 5
23
8) If my affected grown son/daughter has a baby with someone who is unaffected, what are the chances their
baby will be affected?
Again the risk of a person with Joubert having an affected child would be very low. This is because given the relative
rarity of Joubert; we have to assume that the carrier frequency of Joubert is low in the general population. Therefore
unless an affected person married a blood relative, their chances of marrying a Joubert carrier from the general
population would be very low.
9) If my affected grown son/daughter has a baby with another affected person, what are the chances that they
will have an affected baby?
This is a hard question to answer. If we assume "genetic homogeneity" for Joubert (that is all Joubert cases result from
mutations in the same gene), then their risk would be very high (possibly even 190%) because each parent would have
two copies of the same Joubert gene and could only pass mutant copies to their offspring. If on the other hand, Joubert is
heterogeneous (which we suspect it is), then it is possible that two people with Joubert might have in reality mutations in
different genes, therefore their offspring would be carriers (but in this case all would be carriers for two different forms of
Joubert). Obviously this is a very hypothetical situation, but it does come up sometimes when people meet through
support groups. Genetic forms of deafness would be a good example.
10) Discuss what are the benefits of finding the gene: ie. diagnostic tool and more informed family planning,
understanding how the gene works can lead to treatment for one or more problems of the syndrome and the
possibility of gene therapy in the future.
This is hard to answer in a short space. As you mentioned, it would tell us something important about the basic or
fundamental cause of Joubert Syndrome. It would carry the benefits too of use as a tool is genetic counseling, pre-natal
diagnosis and in some cases, diagnosis in some patients who appear to resemble Joubert, but might differ in certain ways
from most patients. Therefore it would assist us in what is known as "genetic nosology" or the clinical sorting out of
syndromes.
Phillip Chance, MD FACMG
Chief, Division of Genetics & Development
University of Washington, School of Medicine
1959 NE Pacific Street, Box 356320
Seattle, WA 98195-6320
206-616-3787
206-221-5132 (fax)
e-mail: pchance@u.washington.edu




.






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ارجو مساعدتنا في نشر رقم الاشتراك بالواتس اب... شكراً

:: صفحات التواصل الاجتماعي لموقع الوراثة الطبية ::

----تويتر------الفيسبوك






[/CENTER]
عبدالرحمن السويد
استشاري طب الاطفال و الامراض الوراثية
http://www.werathah.com/
تنبيه : إن المعلومات الطبية والعلاجية الواردة في هذا الموقع قد روعي فيها الدقة والتوثيق العلمي قدر الإمكان،
وذلك بغرض المعرفة والإطلاع فقط وينصح باستشارة الطبيب المختص عند الحاجة

Abdulrahman Alswaid غير متواجد حالياً   رد مع اقتباس
قديم 06-Nov-2009, 02:28 AM   #5
Abdulrahman Alswaid


مدير عام موقع و منتدى الوراثة الطبية
 
الصورة الرمزية Abdulrahman Alswaid
مورث قمة التميز
رقـم العضويــة: 1
تاريخ التسجيل: Apr 2002
مــكان الإقامـة: السعودية
المشـــاركـات: 19,306
مــرات الشكر: 711
نقـاط الترشيح: 5
نقـــاط الخبـرة: 2538
...

افتراضي

Update on the genetics of Joubert syndrome and genetic testing options
In the past year, there has been a great flurry of genetic discoveries in the field of Joubert syndrome and related
disorders (JSRD), with two new causative genes identified. There are now 5 genes in total that are known to
cause JSRD. In addition, there are 2 more genes that, although we know their general location within the human
genome, have not been discovered yet. One of the challenges in JSRD is that so many different genes can all
cause the same condition. However, within an individual family, only one of these genes is likely to cause
JSRD, which is due to an alteration in both copies of the same gene in the DNA of an affected child. There are
other genetic conditions, such as cystic fibrosis or neurofibromatosis, with only a single causative gene, which
makes identifying the specific mutations much easier.
I would like to take this opportunity to describe the 2 new genes discovered in the past year, and then
summarize what is known about all the genes identified for JSRD. [For details about the first 3 JSRD genes
identified, please see the article on the JSF website (www.jsfrcd.org) linked to “Physician Research” and the
news item on “Update on the genes that cause Joubert syndrome” dated 8-5-06.)
The MKS3 gene was actually identified first in individuals with Meckel-Gruber syndrome (MKS)1. This is a
condition that can be associated with enlarged kidneys with big cysts, brain malformations known as
encephaloceles, and a congenital liver malformation. Some of the MKS fetuses may not survive to be born or
may not survive the newborn period. For the most part, the few children with JSRD who have also had
mutations in this gene have not had the same appearance as MKS2, but have more variable findings. One has
had kidney disease and liver fibrosis. We still have much to learn about this gene and its role in JSRD. This is a
large gene of 28 exons.
The RPGRIP1L gene was first reported this summer by our laboratory and a group based in France3,4. This gene
has 26 exons in length. There appears to be one mutation that occurs more often in children with JSRD due to
this gene, some of whom have developed kidney disease, and others whom have had encephaloceles or extra
fingers or toes. Only a few have had retinal disease that impairs vision and may lead to blindness. Some
newborns with MKS have also had changes in this gene, but these infants have had more severe symptoms and
often, more severe mutations. We think that ~5% of children with JSRD may have changes identified in this
gene.
Table: Genes and estimated frequency in individuals with JSRD5,6
Locus (genetic region) Interval size/Gene Estimated frequency
8q21.13-q22.1 MKS3 gene <10%
16q12.2 RPGRIP1L gene ~5%
6q23 AHI1 gene ~10%
2q13 NPHP1 gene ~1-2%
12q21.3 CEP290 gene ~10%
9q34.3 13 cM ?
11 centromere 6 cM ?
TOTAL <40%
Overall, less than 40% of all families with JSRD will have a mutation identified in one of the 5 known genes.
The physical manifestations for children with AHI1 and NPHP1 gene changes tend to include retinal dystrophy
and kidney problems in some individuals. The clinical manifestations for the other 3 genes (CEP290, MKS3,
and RPGRIP1L) are more variable and overlap with Meckel-Gruber syndrome. Clearly, other genes remain to
11
be identified, and finding the specific gene in a given family may be complicated. At this time, genetic testing
for clinical purposes is available through PreventionGenetics, a genetic testing company based in Wisconsin.
This company can perform deletion analysis for NPHP1, and full sequence analysis of AHI1, MKS3, CEP290,
and RPGRIP1L. Check with your geneticist and insurance company before pursuing testing for these genes, as
it can be expensive if not covered by your policy. (Please see the companion article on “Genetic Testing and
Joubert Syndrome” for a description of genetic testing and a discussion of the pros and cons of testing in JSRD.)
If the genetic cause of JSRD is known based on testing by PreventionGenetics, and you have worked with our
research group, we would appreciate knowing those results, as this helps us understand how the known genes
cause JSRD and also helps us find new genes for JSRD.
As always, we appreciate your contributions to our research group to identify the genetic causes of Joubert
syndrome and related disorders. We also appreciate the many families who have donated to the JSF & RCD
BioBank to advance the cause of research.
Please contact Dr. Parisi at mparisi@u.washington.edu for more information about the genetics of JSRD. Please
contact Dana Knutzen, MS (genetic counselor and research coordinator) at Dana.Knutzen@seattlechildrens.org
for information about how to participate in research studies. Our toll-free phone number is 1-800-246-6312.
Additional information is available on the University of Washington Joubert Center website at
http://depts.washington.edu/joubert/.
Melissa Parisi, MD, PhD
Medical Advisor, JSF & RCD
January 2008
References:
1. Smith UM, Consugar M, Tee LJ, et al. The transmembrane protein meckelin (MKS3) is mutated in Meckel-
Gruber syndrome and the wpk rat. Nat Genet. 2006 38(2):191-6.
2. Baala L, Romano S, Khaddour R, et al. The Meckel-Gruber syndrome gene, MKS3, is mutated in Joubert
syndrome. Am J Hum Genet 2007;80(1):186-94.
3. Arts HH, Doherty D, van Beersum SEC, et al. Mutations in the gene encoding the basal body protein
RPGRIP1L, a nephrocystin-4 interactor, cause Joubert syndrome. Nat Genet. 2007 Jul;39(7):882-8.
4. Delous M, Baala L, Salomon R, et al. The ciliary gene RPGRIP1L is mutated in cerebello-oculo-renal
syndrome (Joubert syndrome type B) and Meckel syndrome. Nat Genet. 2007 Jul;39(7):875-81.
5. Parisi MA, Doherty D, Chance PF, et al. 2007. Joubert syndrome (and Related Disorders) [OMIM 213300].
Eur. J. Hum. Genet., 15(5):511-21.
6. Parisi MA and Glass IA. Joubert syndrome. In: GeneReviews at GeneTests-GeneClinics: Medical Genetics
Information Resource [database online]. Copyright, University of Washington, Seattle. 1997-2008. Available at
http://www.genetests.org.






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:: صفحات التواصل الاجتماعي لموقع الوراثة الطبية ::

----تويتر------الفيسبوك






[/CENTER]
عبدالرحمن السويد
استشاري طب الاطفال و الامراض الوراثية
http://www.werathah.com/
تنبيه : إن المعلومات الطبية والعلاجية الواردة في هذا الموقع قد روعي فيها الدقة والتوثيق العلمي قدر الإمكان،
وذلك بغرض المعرفة والإطلاع فقط وينصح باستشارة الطبيب المختص عند الحاجة

Abdulrahman Alswaid غير متواجد حالياً   رد مع اقتباس
قديم 06-Nov-2009, 02:28 AM   #6
Abdulrahman Alswaid


مدير عام موقع و منتدى الوراثة الطبية
 
الصورة الرمزية Abdulrahman Alswaid
مورث قمة التميز
رقـم العضويــة: 1
تاريخ التسجيل: Apr 2002
مــكان الإقامـة: السعودية
المشـــاركـات: 19,306
مــرات الشكر: 711
نقـاط الترشيح: 5
نقـــاط الخبـرة: 2538
...

افتراضي

Genetic Testing and Joubert Syndrome
Genetic disorders, such as Joubert syndrome and other related cerebellar disorders (JSRD), are caused by
alterations in a gene. Many genetic disorders, including JSRD, can be caused by changes in several different
genes.
What is a Gene?
Within each cell of your body is a unique set of
blueprints that determines how your body looks
and functions. These blueprints are found within
the cell’s DNA (deoxyribonucleic acid).
Specific segments of DNA, called genes, contain
the instructions for making specific body
proteins. One protein may help to determine the
color of your eyes while another helps to control
a specific chemical reaction within your body.
Sometimes, even a small error in one gene can
cause severe health problems.
image courtesy of U.S. Department of Energy
Human Genome Program, http://www.ornl.gov/hgmis
Genes are found in specific segments of DNA, which is tightly packaged within structures called
chromosomes. Every human cell contains 46 chromosomes, arranged in 23 pairs, with one member
of each pair inherited from the mother and the other inherited from the father. After conception, these
46 chromosomes duplicate again and again to pass on genetic information to each new cell in the
developing child.
What is Genetic Testing?
Genetic tests look for abnormalities in a person's genes, which involves looking directly at the DNA obtained
from a person's blood cells, body fluids or tissues. The abnormality can be relatively large — a piece of a
chromosome, or even an entire chromosome, may be missing or added. Sometimes the change is very small
— as little as one extra, missing or altered chemical base within the DNA strand. Some errors may cause
genes to be amplified (too many copies), over-expressed (too active), inactivated or lost altogether. Sometimes
pieces of chromosomes become transposed, or switched, to an incorrect location.
Doctors can now pinpoint missing or defective genes for more than 1000 genetic disorders through genetic
testing. The type of genetic test needed to make a specific diagnosis depends on the particular genetic
condition that a doctor suspects.
Genetic Testing for Joubert Syndrome and Related Disorders
Joubert syndrome and other related disorders are passed down from parents to offspring as autosomal
recessive traits. This means that, in order for a child to be affected with a JSRD, both parents must each carry
one altered copy of the gene responsible for the disorder. JSRD-affected individuals will have two altered
copies of the responsible gene. A mother and father who are both carriers will have a 25% chance of having a
child with JSRD in each pregnancy.
8
In the case of JSRD, scientists look for missing and/or altered copies of the genes known to be responsible for
the disorder. As a result of a partnership among researchers studying JSRD, the Joubert Syndrome
Foundation & Related Cerebellar Disorders, and PreventionGenetics, a genetics testing company, genetic
testing for the five identified JSRD genes is now available to families and can be arranged by a physician. The
genes known to cause JSRD are: AHI1, CEP290, MKS3, NPHP1, and most recently, RPGRIP1L. Additionally,
there are more causative genes that are—as yet—still unknown.
Individuals with JSRD found to have mutations in the AHI1 gene often have impaired vision due to
pigment differences in the retina, called retinal dystrophy. Approximately 11% of all JSRD patients
would receive a positive test result for mutations in the AHI1 gene.
CEP290 abnormalities have been identified in some JSRD patients with nephronophthisis and/or retinal
dystrophy. Perhaps another 4-10% of all JSRD cases may be a result of alterations to this gene.
MKS3 was identified as a cause of JSRD in early 2007. Alterations in the MKS3 gene are responsible
for both JSRD and Meckel-Gruber Syndrome. These two disorders have overlapping clinical features.
Although data is still limited, up to 10% of JSRD cases may be a result of alterations to the MKS3 gene.
NPHP1 is associated with a progressive form of kidney disease called nephronophthisis. It is estimated
that no more than 5% of those with a JSRD would test positive for a deletion in this gene.
The newest gene for JSRD, RPGRIP1L, was just identified in the summer of 2007. There is evidence
that this gene also causes Meckel-Gruber syndrome. It appears to account for about 5% of all cases of
JSRD.
Although researchers are beginning to make connections between abnormalities in each of the aforementioned
genes and the symptoms of affected individuals, it is still difficult to determine which gene is involved in a
particular patient by their symptoms alone.
Pros and Cons of Genetic Testing
Genetic testing for the JSRD genes is typically done to confirm a diagnosis or to determine if an individual is a
carrier for the disorder. A negative test result can, at least, tell doctors where not to look in the future. A
positive test result can relieve the uncertainty of “not knowing”, direct a physician toward appropriate
treatments, and enable couples to make informed decisions about their reproductive future. Sometimes, the
results of genetic testing do not provide a clear answer—and this can be frustrating. As a result, the decision
to undergo genetic testing is a very personal one.
Pros:
• Confirm a JSRD diagnosis.
• Individuals can find out whether they are a carrier for JSRD.
• Knowing which gene is abnormal may, especially in the future, indicate specific health problems that a
patient is likely to develop and may result in better healthcare management.
• Couples of reproductive age can use the knowledge of their carrier status to make educated decisions
regarding their reproductive future.
• Many families and professional geneticists believe that knowledge of the specific genetic causes of
JSRD in patients and family members is desirable to allow better understanding of these conditions.
Cons:
• Although genetic tests can identify a particular causative gene, they can't always predict how severely
affected the individual will be.
• Genetic testing for JSRD is difficult and costly. Some insurance plans will cover the costs for genetic
tests, while others will not. You will have to contact your insurance provider in advance of testing to
see if these genetic tests -- which can cost between $200 and $6000--are covered under your plan.
9
• Sometimes, the results of genetic testing are not definitive. Only one of two causative mutations may be
identified in a JSRD gene, or a genetic change of unknown significance may be identified. In this
situation, it may be difficult to interpret the results and provide predictive information or prenatal testing
options for the family in the future.
• There is a small possibility that the results of genetic testing could be used against you and your family,
particularly by employers and insurance companies. Many states have passed legislation to prohibit
genetic discrimination, and Congress appears to be close to passing Federal anti-genetic discrimination
legislation.
• It is believed that less than 40% of individuals with JSRD will have a mutation identified in one of the 5
known genes. Many of our families are often dealing with troubling uncertainties about their own future
and that of their children, as there are no preventive measures or cures for Joubert syndrome. If you
decide to pursue genetic testing, the information you receive may not offer the answers that you seek.
Your doctor may refer you to a clinical M.D. geneticist or genetic counselor, as the decision about whether to
be tested for JSRD is complex. These professionals are trained to help you weigh the scientific, emotional and
ethical considerations that impact this decision. Universities and medical centers often have affiliated
geneticists and genetic counselors, or can provide referrals to a counselor or genetics clinic.
For More Information
GeneTests.org (www.genetests.org) provides educational materials, expert-authored publications of specific
diseases, and international directories of genetic testing laboratories and clinics.
PreventionGenetics, in Marshfield, WI, offers genetic testing that is available to interested families and can be
arranged through a physician, geneticist, or genetic counselor. To see a complete listing of the genetic tests
currently available for JSRD, go to www.preventiongenetics.com
The Joubert Syndrome Foundation & Related Cerebellar Disorders (www.jsfrcd.org) is an international network
of parents who share knowledge, experience, and emotional support. The JSF&RCD plays an important role
in educating physicians and their support teams as well as increasing public awareness of and promoting
research in JSRD.
Sources:
• “An Introduction to Genetics and Genetic Testing”, www.kidshealth.org
• Department Of Energy, Office of Biological and Environmental Research, Human Genome Program
• GeneReview, “Joubert Syndrome”, www.genetests.org
• “Genetics FAQ”, www.medem.com
• “Gene Testing”, www.medem.com
• National Human Genome Research Institute, National Institutes of Health
01/2008
Joubert Syndrome Foundation & Related Cerebellar Disorders
Email: info@jsfrcd.org website: www.jsfrcd.org






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[/CENTER]
عبدالرحمن السويد
استشاري طب الاطفال و الامراض الوراثية
http://www.werathah.com/
تنبيه : إن المعلومات الطبية والعلاجية الواردة في هذا الموقع قد روعي فيها الدقة والتوثيق العلمي قدر الإمكان،
وذلك بغرض المعرفة والإطلاع فقط وينصح باستشارة الطبيب المختص عند الحاجة

Abdulrahman Alswaid غير متواجد حالياً   رد مع اقتباس
قديم 06-Nov-2009, 02:29 AM   #7
Abdulrahman Alswaid


مدير عام موقع و منتدى الوراثة الطبية
 
الصورة الرمزية Abdulrahman Alswaid
مورث قمة التميز
رقـم العضويــة: 1
تاريخ التسجيل: Apr 2002
مــكان الإقامـة: السعودية
المشـــاركـات: 19,306
مــرات الشكر: 711
نقـاط الترشيح: 5
نقـــاط الخبـرة: 2538
...

افتراضي

Recommendations for Evaluation and Monitoring of Patients with
Joubert Syndrome and Related Disorders
Dear Healthcare Professional,
Joubert Syndrome and Related Disorders are a group of developmental brain disorders characterized clinically by
disturbances of breathing rhythm, ataxia, oculomotor abnormalities, developmental delays, and hypotonia. These
disorders are characterized on brain imaging by cerebellar vermis hypoplasia and the “molar-tooth” sign of the brainstem.
From our review of clinical records from patients in the Joubert Syndrome Foundation, we have found many with coexisting
medical conditions at a frequency sufficient to warrant a set of guidelines for the evaluation and monitoring
of all patients with Joubert Syndrome and Related Disorders. These evaluations are necessary for two reasons.
First is for proper diagnosis of the child, as we find that approximately 20% of patients display features indicating a
subtype of Joubert syndrome or a related syndrome. Second is to try to prevent medical complications from these
associated conditions, which through proper screening might be avoided. However, because our total knowledge of
Joubert syndrome and its complications are limited, our recommendations will need to be evaluated and changed as new
information becomes available.
Patients with Joubert Syndrome and Related Disorders, in addition to the features mentioned above, have
displayed the following features:
1. Abnormal electroretinogram, indicating co-existent retinal dysplasia and visual impairment.
2. Optic colobomas, which may also limit vision.
3. Kidney disease, which may include juvenile nephronophthisis or cystic dysplastic kidneys. In some patients, the kidney
disease has progressed to end-stage renal failure that required dialysis or transplantation.
4. Liver fibrosis with or without compromised liver function.
5. Tongue tumors (hamartomas), enlarged tongues, multiple frenulae or other unusual anomalies of the mouth.
6. Polydactyly of fingers or toes that may be simple or complex.
7. Hypothalamic disorders, sometimes related to a hypothalamic hamartoma.
8. Additional subtle variation in the appearance of brain structures, including polymicrogyria or encephalocele.
Because of these findings, we recommend the following evaluations for patients with Joubert Syndrome and Related
Disorders.
Diagnostic Evaluations (Initial)
1. Careful physical examination to look specifically for these co-existent features.
2. Pediatric neurological evaluation for careful assessment of development and cerebellar function.
3. Medical genetics evaluation with attention focused on genealogy, growth, polydactyly, micro/macrocephaly, facial
dysmorphism, clefts, lingual nodules, genitalia, and other anomalies.
4. Evaluation of oromotor function by a trained occupational or speech therapist
5. Brain MRI with axial, coronal, sagittal images (ideally with 3 mm axial planes through midbrain and pons) and review of
the images by one of the Medical Advisors of the Joubert Syndrome Foundation.
6. Developmental assessment using the Bayley Scale for children less than 3 years and specific age-appropriate
motor/speech/language testing for older children.
7. Sleep history with attention to apnea/hyperpnea. Polysomnogram in all children diagnosed under the age of 1. After
the age of 1, this test may be useful if the child has symptoms of sleep apnea.
8. Baseline pediatric ophthalmologic dilated eye exam to test for retinal dysplasia and coloboma. If visual problems are
suspected, a visual evoked potential (VEP) study may be a useful test that does not require sedation and can be
performed as early as 6 months of age.
9. Baseline electroretinogram (ERG) if possible. Ideally, this should be done between the ages of 8 months and 3 years,
when the sedation required is minimal.
10. Specific ocular motility examination (with electrooculogram in older children).
11. Abdominal ultrasound scan with attention to kidneys and liver.
12. Renal evaluation: Blood urea nitrogen (BUN), creatinine, complete blood count (CBC), and first-morning void
urinalysis with specific gravity for concentrating ability. A baseline blood pressure should be obtained.
13. Liver function tests (LFTs) to include transaminases, albumin and bilirubin.
14. High resolution karyotype.
15. Referral of the child to one of the Medical Advisors of the Joubert Syndrome Foundation to discuss results of testing or
for questions.
Annual Evaluations (Yearly)
1. Annual pediatric and neurological evaluation to monitor systemic or motor abnormalities.
2. Patients may have progressive kidney failure with the first manifestation being reduced urine concentrating ability or
anemia. Therefore, annual abdominal ultrasounds, BUN, creatinine, CBC, first-morning void urinalysis, and blood
pressure measurements, are recommended until at least age 20 years.
3. Ophthalmologic abnormalities may be progressive. Therefore, annual ophthalmologic evaluation of retina is
recommended with follow-up ERG if indicated by the ophthalmologist.
4. Annually monitor growth and sexual maturation with endocrinologic evaluation if indicated
5. Neuropsychological evaluation when patient is able to cooperate with testing.
6. Periodic developmental assessments as appropriate.
7. Liver evaluation by annual ultrasound (as for kidneys) and liver function tests.
8. Patients may have problems with swallowing from large tongues, thus need ongoing evaluation for oromotor function
and symptoms of obstructive apnea.
These are guidelines only. Individual patients may have unique needs and management may need to be individualized.
If you have any questions about Joubert Syndrome and Related Disorders, the Joubert Syndrome Foundation, or other
matters, please do not hesitate to contact one of us.
Sincerely,
Dr. Joseph G. Gleeson, Dr. Melissa A. Parisi, Dr. Bernard L. Maria, Dr. William B. Dobyns
Medical Advisors of the Joubert Syndrome Foundation






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ارجو مساعدتنا في نشر رقم الاشتراك بالواتس اب... شكراً

:: صفحات التواصل الاجتماعي لموقع الوراثة الطبية ::

----تويتر------الفيسبوك






[/CENTER]
عبدالرحمن السويد
استشاري طب الاطفال و الامراض الوراثية
http://www.werathah.com/
تنبيه : إن المعلومات الطبية والعلاجية الواردة في هذا الموقع قد روعي فيها الدقة والتوثيق العلمي قدر الإمكان،
وذلك بغرض المعرفة والإطلاع فقط وينصح باستشارة الطبيب المختص عند الحاجة

Abdulrahman Alswaid غير متواجد حالياً   رد مع اقتباس


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