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(molar tooth sign). 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. The International Statistical Classification of Diseases and Related Health Problems (commonly known by the abbreviation ICD) is a detailed description of known diseases and injuries. ... The following codes are used with International Statistical Classification of Diseases and Related Health Problems. ... // Q00-Q99 - Congenital malformations, deformations and chromosomal abnormalities (Q00-Q07) Congenital malformations of the nervous system (Q00) Anencephaly and similar malformations (Q01) Encephalocele (Q02) Microcephaly (Q03) Congenital hydrocephalus (Q04) Other congenital malformations of brain (Q05) Spina bifida (Q06) Other congenital malformations of spinal cord (Q07) Other congenital malformations of nervous... The International Statistical Classification of Diseases and Related Health Problems (commonly known by the abbreviation ICD) is a detailed description of known diseases and injuries. ... The following is a list of codes for International Statistical Classification of Diseases and Related Health Problems. ... The Diseases Database is a free website that provides information about the relationships between medical conditions, symptoms, and medications. ... A genetic disorder, or genetic disease is a disease caused by abnormal expression of one or more genes in a person causing a clinical phenotype. ... In animals, the brain, or encephalon (Greek for in the head), is the control center of the central nervous system. ... Part of the structure of animal brains, the cerebellar vermis is a narrow, wormlike structure between the hemispheres of the cerebellum. ... Mostly enveloped by the cerebrum and cerebellum (blue), the visible part of brainstem is shown in black. ... Ataxia (from Greek ataxiā, meaning failure to put in order) is unsteady and clumsy motion of the limbs or trunk due to a failure of the gross coordination of muscle movements. ... Hypotonia is a condition of abnormally low muscle tone (the amount of tension or resistance to movement in a muscle), often involving reduced muscle strength. ... This article is about the medical term, epileptic seizure, as distinct from psychogenic non-epileptic seizure. ...

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. Mutations in a gene of unknown function called AHI1 is associated with a subset of Joubert syndrome cases. In some rare cases of Joubert syndrome, mutations have been found in NPHP1 which is also associated with nephronophthisis, a cystic kidney disorder. This stylistic schematic diagram shows a gene in relation to the double helix structure of DNA and to a chromosome (right). ... In biology, mutations are changes to the genetic material (either DNA or RNA). ...

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