LGMD is the term used to describe a group of diseases that cause weakness and wasting of the muscles in the arms and legs. People with LGMD may have trouble walking at first, and many eventually need a wheelchair. Some people with LGMD also experience weakness of the heart muscle.
More than a decade ago, scientists identified a specific genetic location associated with LGMD. However, it proved difficult to identify which specific genes were involved and exactly how genetic mutations act on the body in the development of LGMD.
Scientists supported in part by the NICHD Intellectual and Developmental Disabilities Branch analyzed detailed genetic information from nine families affected by the most common type of LGMD. The researchers discovered a group of mutations in individuals with LGMD. All these mutations resulted in increases in a specific type of protein that has also been associated with other conditions, including Parkinson’s Disease. Increases in one form of this protein resulted in toxic effects on muscle cells, leading to some of the symptoms of LGMD (PMID: 22366786).
Researchers are now looking at the possibility of developing treatments that could be administered early, before the damage from LGMD begins.