Scientists have gained significant new insight into fragile X syndrome -- the most common cause of inherited intellectual disability (ID) -- by studying the case of a unique individual without the disorder, but with two of its classic symptoms. In patients with fragile X, a key gene (FMR1) on the X-chromosome is completely disabled, eliminating a protein that regulates electrical signals in the brain and causing a host of behavioral, neurological, and physical symptoms. The unique patient in this study, by contrast, had only a single base pair error in this key gene and exhibited only two classic traits of fragile X syndrome-- intellectual disability and seizures -- allowing the researchers to parse out a previously unknown role for the FMR1 gene and the protein it codes for. "This individual case has allowed us to separate two independent functions of the fragile X protein in the brain," said co-senior author Vitaly A. Klyachko, Ph.D., Associate Professor of Cell Biology and Physiology at the Washington University School of Medicine in St. Louis, Missouri. "By finding the mutation, even in just one patient, and linking it to a partial set of traits, we have identified a distinct function that this gene is responsible for and that is likely impaired in all people with fragile X." This important new research was published online on January 5, 2015 in PNAS by collaborating investigators at Washington University and at Emory University School of Medicine in Atlanta, Georgia. Eminent human geneticist Stephen T. Warren, Ph.D.Login Or Register To Read Full Story