spinal muscular atrophy
Findings
No curated finding names spinal muscular atrophy yet. Everything below is reference data from Mondo, HPO and GenCC, not evidence about what affects it.
Definition
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.
Definition from the Mondo Disease Ontology (MONDO:0001516), read 2026-09-29. CC BY 4.0.
Genes
2 genes
Germline variants in the gene encoding each protein, as classified by GenCC submitters, each in their own words. Limited, disputed and refuted submissions are listed too.
- SMN1; SMN2HGNC:11117
- Definitive · Myriad Women's Health · Autosomal recessive · 2018
- RBM7HGNC:9904
- Moderate · PanelApp Australia · Autosomal recessive · 2025
Where it sits
- Narrower terms (19)
- adult-onset proximal spinal muscular atrophy, autosomal dominant
- autosomal recessive distal spinal muscular atrophy 1
- autosomal recessive distal spinal muscular atrophy 2
- bulbospinal muscular atrophy
- infantile-onset X-linked spinal muscular atrophy
- neuronopathy, distal hereditary motor, autosomal dominant
- neuronopathy, distal hereditary motor, autosomal recessive 3
- neuronopathy, distal hereditary motor, autosomal recessive 4
- neuronopathy, distal hereditary motor, autosomal recessive 5
- proximal spinal muscular atrophy
- scapuloperoneal spinal muscular atrophy, autosomal dominant
- scapuloperoneal spinal muscular atrophy, autosomal recessive
- spinal muscular atrophy type 0
- spinal muscular atrophy with respiratory distress type 2
- spinal muscular atrophy-progressive myoclonic epilepsy syndrome