Joubert syndrome is a rare genetic disorder that affects the area of the brain that controls balance and coordination. The disorder is characterized by absence or underdevelopment of a part of the brain called the cerebellar vermis and a malformed brain stem. The most common features include ataxia (lack of muscle control), an abnormal breathing pattern called hypernea , sleep apnea, abnormal eye and tongue movements, and hypotonia. Other malformations such as extra fingers and toes, cleft lip or palate, tongue abnormalities, and seizures may also occur. There may be mild or moderate retardation.

Treatment for Joubert syndrome is symptomatic and supportive. Infant stimulation and physical, occupational, and speech therapy may benefit some patients. Infants with abnormal breathing patterns should be monitored.

The prognosis for individuals with Joubert syndrome varies. Some patients have a mild form with minimal motor disability and good mental development, while others may have severe motor disability and moderate mental retardation.

Two genes that are mutated in individuals with Joubert syndrome have been identified. Mutation in gene of unknown function called AHI1 is associated with the majority of Jourbert syndrome cases. In cases where an individual has Joubert syndrome with progressive kidney disease to a gene called NPHP1 is mutated in addition to AHI1.

References

• Ferland R. J. et al. Abnormal cerebellar development and axonal decussation due to mutations in AHI1 in Joubert syndrome. Nature Genetics, September 2004, 36:1008-1013.
• Parisi M. A. et al. The NPHP1 gene deletion associated with juvenile nephronophthisis is present in a subset of individuals with Joubert syndrome. American Journal of Human Genetics, July 2004, 75:82-91.

External links

• The Joubert Syndrome Foundation Home Page
• NINDS Joubert Syndrome Information Page
• Researchers Identify Joubert Syndrome Genes