Scientists solve mystery of nerve disease genes

For several years, scientists have been pondering a question about a genetic disease called Charcot-Marie-Tooth (CMT) disease type 2D: how can different types of mutations, spread out across a gene, produce the same condition?

Now, a team of scientists at The Scripps Research Institute may have found the answer. By studying a gene called GARS, which is mutated in individuals with the disease, the team found that all the mutations have one thing in common: they cause the tightly coiled three-dimensional shape of the resulting protein to shift open.

The more open configuration creates a space for other proteins to bind, causing havoc. ''That is the basis for potential disease-causing interactions,'' said Scripps Research Associate Professor Xiang-Lei Yang, senior author of the study, ''but also for potential therapeutic intervention.'' It is possible that scientists could develop drugs to fit into the open area, blocking its access to other proteins.

The findings, to be published this week in the online issue of Proceedings of the National Academies of the Sciences (PNAS) help scientists explain how CMT type 2D occurs. The results may also have implications for other diseases, such as amyotrophic lateral sclerosis (ALS), also known as Lou Gehrig's disease.

A Puzzling Disease

Named after the three physicians who first reported the disease in 1886, CMT is the most common inherited neurological disorder, estimated to affect one in 2,500 people. Although it is not fatal, CMT causes progressive weakness and wasting of muscles in the feet, legs, hands, and forearms by striking down the nerves that reach down into these muscles.