Gene Mutation That Causes Blindness in Yemenite Jews Found
Researchers at the Technion-Israel Institute of Technology have discovered a genetic mutation that causes the hereditary eye disease Retinitis pigmentosa (RP) in Yemenite Jews. The findings were published in the December 2007 issue of "Investigative Ophthalmology & Visual Science."
Most sufferers of RP, which is a wide-ranging group of degenerative retinal disorders, begin losing night vision during childhood. They later slowly lose peripheral vision, and in most cases are totally blind by age 20. RP affects one in 4,000 people worldwide, making it the most common cause of hereditary retina deterioration. To date, more than 50 genes have been implicated in the disorder.
By studying DNA samples from families in which RP is prevalent, the research team led by Dr. Tamar Ben-Yosef of the Technion Faculty of Medicine found that one in 23 Yemenite Jews carry a mutation in a gene called CERKL (the mutation was found to be extremely rare in other ethnic groups). With DNA samples taken from additional Yemenite families, the researchers confirmed the high prevalence of the CERKL mutation - and its causal relationship to Retinitis pigmentosa - in that group.
Since the mutation is recessive, a person is only at risk for the disease if both parents are carriers. If both parents carry the gene, there is a 25% chance their children will develop the disease.
"There is no cure for RP at this time," says Ben Yosef. "The identification of the different genes involved in this disease, and characterization of their function in normal vision and in disease pathology is a first step towards developing effective treatments."
Until such treatments are developed, the researchers are encouraging Israeli medical centers to test for the CERKL mutation. Such a step, they say, would enable the identification of carriers and the provision of genetic counseling to families at risk.
The research team also included Technion graduate student Noa Auslander, and Prof. Eyal Banin and Dr. Dror Sharon from the Hadassah Medical Center in Jerusalem.