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
SPBC19C7.07c SPAC2G11.08c SPAC20G8.07c SPCC613.09 SPAPB17E12.07c SPAC959.10 SPCC757.08 SPBC17D1.03c SPAC2F7.13c SPBC29A3.01 SPAC6C3.02c SPAC22A12.12c SPBC3E7.02c SPBC30D10.09c SPBC16G5.05c SPAC17C9.12 SPCC737.07c SPBC1604.21c SPAC3A11.04 SPAC3C7.12 SPCC338.06c SPAC3F10.03 SPAC1093.06c