Inside the Motor Molecule
It’s a rare, inherited disorder that begins in infancy or early childhood. Children usually survive but end up needing leg braces and wheelchairs as the muscles in their legs weaken and fail. It’s called spinal muscular atrophy with lower extremity predominance or SMA-LED. As previously suspected—and recently shown by Cedars-Sinai researchers—some cases are caused by a genetic mutation on a molecule inside motor neurons, the nerve cells that control muscles.
The molecule works like a forklift inside the cells: It helps move cell parts from one place to another, helping the motor neurons develop and stay organized and healthy. When the gene mutation occurs, the forklift stalls, the nerve cell malfunctions, and the muscles fail.
Although the study focused on a rare disease, the discovery of this particular genetic mutation revealed that the molecular motor is crucial for development and maintenance of motor neurons in general. “We hope this will provide insight into the common form of spinal muscular atrophy and also Lou Gehrig’s Disease [amyotrophic lateral sclerosis (ALS)],” says Robert H. Baloh, MD, PhD, director of Cedars-Sinai Medical Center’s Neuromuscular Division and senior author of an Annals of Neurology article describing the new findings.
Dr. Baloh, an expert in treating and studying neuromuscular and neurodegenerative diseases, joined Cedars-Sinai in early 2012, working with other physicians and scientists in the Department of Neurology and the Regenerative Medicine Institute to establish one of the most comprehensive neuromuscular disease treatment and research teams in California.