spinal muscular atrophy
A motor neuron disease that affect the muscles, and characterized by muscle weakness and atrophy resulting from progressive degeneration and irreversible loss of the anterior horn cells in the spinal cord (i.e., lower motor neurons) and the brain stem nuclei. The severity of the condition; the associated signs and symptoms; and the age at which symptoms develop varies by subtype. In general, people with spinal muscular atrophy (SMA) experience progressive weakness and atrophy of muscles involved in mobility, the ability to sit unassisted, and head control. Breathing and swallowing may also be affected in severe cases. SMA is generally caused by changes (mutations) in the SMN1 gene and is inherited in an autosomal recessive manner. Extra copies of the SMN2 gene modify the severity of SMA. Rare autosomal dominant (caused by mutations in DYNC1H1, BICD2, or VAPB genes) and X-linked (caused by mutations in UBA1) forms of SMA exist. Treatment is based on the signs and symptoms present in each person.
MONDO:0005336
myopathy
excluded_subClassOf
MONDO:0003182
anterior horn disorder
is_a
MONDO:0024257
hereditary motor neuron disease
is_a
SPBC29A3.01 SPAC22A12.12c SPAC3F10.03 SPAC20G8.07c SPCC737.07c SPAC2F7.13c SPCC613.09 SPBC17D1.03c SPAC959.10 SPBC30D10.09c SPAC17C9.12 SPBC16G5.05c SPAC1093.06c SPAPB17E12.07c SPAC6C3.02c SPBC1604.21c SPBC19C7.07c SPAC3C7.12 SPAC2G11.08c SPBC3E7.02c SPAC3A11.04 SPCC338.06c SPCC757.08