Joubert syndrome 2 (JBTS2) is a disease that causes abnormalities in the brain structure leading to developmental delay, the inability to coordinate muscle movement, involuntary eye movements, and difficulty moving the eyes from side to side. Individuals may also have intellectual disability.
At birth, children with JBTS2 have poor muscle tone. Their eyes rapidly move involuntarily and may rotate inward. They often have difficulty eating due to problems coordinating their muscle movement and breathing problems due to the brain structure abnormalities. Some children with JBTS2 have additional fingers and/or toes (polydactyly). Some children with JBTS2 will have kidney problems leading to kidney failure in adolescence.
Children with JBTS2 all have delayed mental and physical development. They may be mildly to severely mentally retarded, though a few individuals have attended college. In the first few years of life, their eye problems often improve, leading to normal vision.
JBTS2 is most common in Ashkenazi Jews, of whom 1 in 34,000 is affected.
There is no cure for Joubert syndrome 2. A medical team can address symptoms as they arise. Regular examinations are necessary, since individuals vary from one another in the symptoms they will have. For example infants with difficulty eating should be monitored to ensure they're receiving proper nutrition. Physical and occupational therapy may also be helpful. Children with JBTS2 should also be monitored for eye and kidney problems.
The prognosis for a person with JBTS2 varies. Some will have milder forms of mental retardation and less severe ataxia (lack of muscle control) while others will have more severe mental retardation and movement problems. A minority will have a shorter lifespan due to kidney or liver failure and breathing abnormalities.
A network of families affected by Joubert syndrome who share information, experiences, and support.
A page of information about Joubert Syndrome from the U.S. Government's National Institutes of Health.