This document discusses spinal muscular atrophy (SMA). SMA is caused by a mutation in the SMN1 gene located on chromosome 5q13. This gene normally produces SMN proteins which are important for survival of motor neurons. In SMA, little to no SMN proteins are produced, motor neurons cannot function properly, and muscle weakness results. SMA presents in infants as weak muscles, breathing and feeding problems, and in children as worsening respiratory conditions and posture. Treatments focus on supportive care, physical therapy, and braces. SMA has an autosomal recessive inheritance pattern and affects 1 in 6000 people, though 1 in 40 are carriers.