Spinal muscular atrophy (SMA) is usually divided into five main types — 0, 1, 2, 3, and 4 — based on the age at symptom onset. All of these types are caused by mutations in the SMN1 gene. There also are several rarer forms of SMA that are caused by mutations in other genes.
Marisa Wexler, MSMarisa holds a Master of Science in cellular and molecular pathology from the University of Pittsburgh, where she studied novel genetic drivers of ovarian cancer. Her areas of expertise include cancer biology, immunology, and genetics, and she has worked as a science writing and communications intern for the Genetics Society of America.
