Study Opens New Line of Attack on Spinal Muscular Atrophy

Though spinal muscular atrophy (SMA) in its most severe form remains incurable and fatal in early childhood, researchers are sustaining a multipronged counterattack for patients and their families. The first treatment for the disease gained U.S. market approval in December. Now a new discovery led by Brown University scientists deepens the basic understanding of how the genetic mutation that causes SMA appears to undermine the communication between motor neurons and the muscles they control. "We are making progress," said Anne Hart (photo), PhD, Professor of Neuroscience at Brown and senior author of the new study published online on May 2, 2017 in eLife. The open-access article is titled “Decreased MicroRNA Levels Lead to Deleterious Increases in Neuronal M2 Muscarinic Receptors in Spinal Muscular Atrophy Models.” About one in 8,000 children is born with some form of SMA in which mutations in both copies of the gene that code for the survival motor neuron (SMN) protein cripple its production. The end result, which the new study helps to explain, is dysfunction of motor neurons that control muscle along with muscle atrophy and weakness. In the most acute form, Type I, children die by age two as even functions as fundamental as breathing become compromised. With other SMA types, patients can live much longer, but they still suffer significant muscle weakness.