What are the genetic changes related to Joubert syndrome ?
Joubert syndrome and related disorders can be caused by mutations in at least 10 genes. The proteins produced from these genes are known or suspected to play roles in cell structures called cilia. Cilia are microscopic, finger-like projections that stick out from the surface of cells and are involved in chemical signaling. Cilia are important for the structure and function of many types of cells, including brain cells (neurons) and certain cells in the kidneys and liver. Cilia are also necessary for the perception of sensory input (such as sight, hearing, and smell).  Mutations in the genes associated with Joubert syndrome and related disorders lead to problems with the structure and function of cilia. Defects in these cell structures probably disrupt important chemical signaling pathways during development. Although researchers believe that defective cilia are responsible for most of the features of these disorders, it remains unclear how they lead to specific developmental abnormalities.  Mutations in the 10 genes known to be associated with Joubert syndrome and related disorders only account for about half of all cases of these conditions. In the remaining cases, the genetic cause is unknown.