TUESDAY, Sept. 23, 2003 (HealthDayNews) -- Researchers have found new information about a rare genetic disorder called Joubert syndrome, which affects an area of the brain that controls balance and coordination.
The University of California, San Diego (UCSD) team identified chromosome 11 as a second site for a gene or genes that cause Joubert syndrome. Before this new discovery, chromosome 9 had been the only known site with gene mutations that caused the disorder.
The study is published online in the September issue of the American Journal of Human Genetics.
Joubert syndrome affects about one in 30,000 people. It's characterized by the absence or underdevelopment of a brain region called the cerebellar vermis, and by a malformed brain stem. The most common features of Joubert syndrome include lack of muscle control and decreased muscle tone; an abnormal breathing pattern called hypernea; abnormal eye and tongue movements; and mild or moderate retardation.
"The hunt for genes for this syndrome has been extremely slow and none are currently known, due to the rarity of the syndrome," study senior author Dr. Joseph Gleeson, an assistant professor of neurosciences, says in a news statement.
"The main problem in identifying genes has been the small number of patients appropriate for genetic analysis," Gleeson says.
For this study, he and his colleagues focused on three Middle Eastern families whose relatives had inter-married and passed the genetic defect to several family members.
This new finding may move scientists a bit closer to developing a genetic screening test for Joubert syndrome.
More information
Here's where you can learn more about Joubert syndrome.
