Spinal muscular atrophy

Spinal muscular atrophy (SMA), also known as progressive spinal muscular atrophy, is a group of common autosomal recessive genetic disorders characterized by progressive muscle weakness and atrophy due to the degeneration of anterior horn cells in the spinal cord. Based on the age of onset and the severity of the disease, SMA can be divided into four types: Types I-III are known as childhood-onset spinal muscular atrophy, which are autosomal recessive genetic disorders and are the most common fatal genetic diseases in infancy. Type IV is characterized by onset at 20-30 years of age or older and can present with different inheritance patterns, including autosomal recessive, autosomal dominant, and X-linked recessive.