spinal muscular atrophy, type 1
Findings
No curated finding names spinal muscular atrophy, type 1 yet. Everything below is reference data from Mondo, HPO and GenCC, not evidence about what affects it.
Definition
A severe infantile form of proximal spinal muscular atrophy characterized by severe and progressive muscle weakness and hypotonia resulting from the degeneration and loss of the lower motor neurons in the spinal cord and the brain stem nuclei.
Definition from the Mondo Disease Ontology (MONDO:0009669), read 2026-09-29. CC BY 4.0.
- Inheritance
- Autosomal recessive inheritance
- Onset and course
- Infantile onset · Neonatal onset · Death in childhood
HPO, annotations 2026-09-02
Features
4 features
What the disease is reported to present with, and how often among people who have it — never how often a feature means the disease. HPO, annotations 2026-09-02.
- Decreased fetal movementHPOHP:0001558
- 22 of 66 reported patients · Fetal onset
- Generalized hypotoniaHPOHP:0001290
- Poor head controlHPOHP:0002421
- Spinal muscular atrophyHPOHP:0007269
Genes
1 gene
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 · Ambry Genetics · Autosomal recessive · 2018
- Strong · Genomics England PanelApp · Autosomal recessive · 2021
- Strong · PanelApp Australia · Autosomal recessive · 2025
- Supportive · Orphanet · Autosomal recessive · 2021
Where it sits
- A kind of
Other names
11 names
Resolves to: spinal muscular atrophy, type 1
- Also called
- severe infantile spinal muscular atrophySMA type 1SMA type ISMA-ISMA1SMNIspinal muscular atrophy-1survival motor neuron spinal muscular atrophyWerdnig Hoffmann diseaseWerdnig-Hoffman diseaseWerdnig-Hoffmann Disease