A team of scientists, including faculty at the University of Massachusetts Medical School (UMMS), have discovered a gene
that influences survival time in amyotrophic lateral sclerosis (ALS, also known as Lou Gehrig's disease). The study, published today in Nature Medicine
, describes how the loss of activity of a receptor called EphA4 substantially extends the lifespan of people with the disease. When coupled with a UMMS study published last month in Nature identifying a new ALS gene (profilin-1) that also works in conjunction with EphA4, these findings point to a new molecular pathway in neurons that is directly related to ALS susceptibility and severity.
"Taken together, these findings are particularly exciting because they suggest that suppression of EphA4 may be a new way to treat ALS," said Robert Brown, MD, DPhil, a co-author on the study and chair of neurology at UMass Medical School.
ALS is a progressive, neurodegenerative disorder affecting the motor neurons in the central nervous system. As motor neurons die, the brain's ability to send signals to the body's muscles is compromised. This leads to loss of voluntary muscle movement, paralysis and eventually respiratory failure. The cause of most cases of ALS is not known. Approximately 10 percent of cases are inherited. Though investigators at UMMS and elsewhere have identified several genes shown to cause inherited or familial ALS, almost 50 percent of these cases have an unknown genetic cause. There are no significant treatments for the disease.
Wim Robberecht, MD, PhD, lead investigator of the Nature Medicine study and a researcher at the University of Leuven in Belgium and the Vesalius Research Center, screened for genes in zebrafish that blunt the adverse effect of the ALS mutant gene SOD1. Through this process, his team identified EphA4 as an ALS modifier. Dr. Robberecht's team went on to show that when this gene is inactivated in mice with ALS, the mice live longer.