Spinal Muscular Atrophies of Childhood

**Definition:** A group of recessive inherited diseases that feature progressive muscular atrophy and hypotonia. They are classified as type I (Werdnig-Hoffman disease), type II (intermediate form), and type III (Kugelberg-Welander disease). Type I is fatal in infancy, type II has a late infantile onset and is associated with survival into the second or third decade. Type III has its onset in childhood, and is slowly progressive. (J Med Genet 1996 Apr:33(4):281-3)

**Tree numbers:** - C10.228.854.468.800 - C10.574.500.812 - C10.574.562.500.750 - C10.668.467.500.750 - C16.320.400.765