Download What is Joubert Syndrome?

Joubert Syndrome
Joubert Syndrome
Jodi McQueen
Stephen F. Austin University
1
Joubert Syndrome
Joubert Syndrome: Pathological condition. Characterized by central nervous
system defects, retinal dystrophy, severe psychomotor retardation, and breathing
problems. Ocular findings similar to Leber’s amaurosis(abnormal saccades and
pursuit), but visually evoked responses are normal. Can be hereditary.
What is Joubert Syndrome?
Marie Joubert (whose name is given to the condition) gave a detailed description
of the syndrome in 1969. She wrote about four siblings (three brothers, one
sister) in one family with abnormal breathing, jerky eye movements , poor mental
development, and ataxia(staggering gait and imbalance). X-ray examination
showed that a particular section of the brain, called the cerebellar vermis, was
absent or not fully formed. This specific brain defect was confirmed during an
autopsy in one of these individuals. Her initial report also described a
sporadic(non-inherited) patient with similar findings, in addition to polydactyly.
Another name for Joubert syndrome is Joubert-Bolthauser syndrome.
Joubert syndrome is a rare brain malformation showing the absence or
underdevelopment of the cerebellar vermis - this is an area of the brain that
controls balance and coordination, and a malformed brain stem.
The most common features of Joubert syndrome in infants include abnormally
rapid breathing (hyperpnea), decreased muscle tone (hypotonia), jerky eye
movements (oculomotor apraxia), mental retardation, and the inability to
coordinate voluntary muscle movements (ataxia).
Physical deformities may be present, such as extra fingers and toes
(polydactyly), cleft lip or palate, and tongue abnormalities. Kidney and liver
abnormalities can develop, and seizures may also occur.
Most cases of Joubert syndrome are sporadic (not inherited). Joubert syndrome
is classified as an auto-somal recessive disorder. Autosomal means that both
males and females can have the condition. Recessive means that both parents
carry a single copy of the responsible gene. Autosomal recessive disorders occur
when a person inherits a particular pair of genes that do not work properly. The
ratio in which this would happen to children of carrier parents is 25% (one in four)
for each pregnancy.
What is the prognosis?
The prognosis for infants with Joubert syndrome depends on whether or not the
cerebellar vermis is partially developed or entirely absent. Some children have a
mild form of the disorder, with minimal motor disability and good mental
development, while others may have severe motor disability and moderate
mental retardation.
Is there any treatment?
Treatment for Joubert syndrome is symptomatic and supportive. Infant
stimulation and physical, occupational, and speech therapy may benefit some
children. Infants with abnormal breathing patterns should be monitored.
Screening for progressive eye, liver, and kidney complications associated with
Joubert-related disorders should be performed on a regular basis.
Functional problems
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Individuals with this condition will have abnormal development of the
retina in the eye, or the iris (coloboma), which can interfere with visual
acuity and processing (CVI)
In Joubert Syndrome,the cerebellar vermis is either absent or incompletely
formed. The brain stem is sometimes quite small. The absence or
abnormal function of these brain tissues causes problems in breathing and
vision, and severe delays in development.
Muscle movement of the eye is also affected in Joubert syndrome. It is
common for the eyes to have a quick, jerky motion of the pupil, known as
nystagmus. The retina (this is the tissue in the back of the eye that
receives and transmits visual signals to the brain) may be abnormal.
Some individuals (most often in males) may have a split in the tissue in
the iris of the eye. Each of these problems will affect their vision, and eye
surgery might not be beneficial.
Sources:
1. http://www.ninds.nih.gov/disorders/joubert/joubert.htm
2. Dictionary of Eye Terminology 5th Ed., Barbara Cassin and Melvin Rubin, MD, Editor,
2006, Gainsville, FL., pg. 148
3. http://www.jsfrcd.org/
4. http://www.answers.com/topic/joubert-syndrome
5. http://www.novelguide.com/a/discover/gegd_0002_0001_0/gegd_0002_0001_0_00228.ht
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