A group of
These include autosomal recessive neuromuscular disorders characterized by degeneration of spinal cord anterior horn cells leading to symmetrical muscle weakness and atrophy
Type 1: Severe infantile SMA (Werdnig-Hoffman)
Type 2: Infantile chronic SMA
Type 3: Juveline SMA (Wohlfart-Kugelberg-Welander)
Type 4: Adult onset SMA
Kennedy disease is an X-linked recessive form occurring only in men.