sma stands for spinal muscular atrophy. Survival of the disease varies depending on the type of disease. Children can die within 2 years of age or may survive into adulthood, with some patients having no impact on life expectancy. Spinal muscular atrophy is an autosomal disorder, a group of diseases caused by degeneration of motor neurons in the anterior horn of the spinal cord leading to muscle weakness and muscle atrophy. The ultimate cause of death in spinal muscular atrophy is respiratory failure due to paralysis of the respiratory muscles. There are four types of spinal muscular atrophy, and life expectancy varies by type. Type 1, the infantile form, begins within the first 6 months of life and presents with rapidly progressive, symmetrical weakness of the limbs, with the majority of patients dying within 2 years of age. Type 2 is the intermediate type, which starts 6 to 18 months after birth and progresses more slowly than type 1, and most patients can live to adulthood. Type 3 is the adolescent type, patients usually start the disease after 18 months of life, early motor development is normal, can walk alone, some of the time of walking alone is delayed. With age, there is a predominantly proximal muscle weakness, and life expectancy is not shortened or mildly decreased. Type 4, the adult type, has normal early motor development, adult onset, proximal limb weakness, slow progression, and no reduction in life expectancy. It is recommended that patients with suspected spinal muscular atrophy or with a family history of spinal muscular atrophy should seek early medical attention for a definitive diagnosis and prompt treatment to slow down the progression of the disease.