autosomal recessive distal spinal muscular atrophy 2
Findings
No curated finding names autosomal recessive distal spinal muscular atrophy 2 yet. Everything below is reference data from Mondo, HPO and GenCC, not evidence about what affects it.
Definition
Distal hereditary motor neuropathy, Jerash type is a rare, genetic neuromuscular disease characterized by progressive, symmetrical, moderate to severe, distal muscle weakness and atrophy, without sensory involvement, first affecting the lower limbs (towards the end of the first decade) and then involving (within two years) the upper extremities. Patients typically develop foot drop, pes varus, hammer toes and claw hands. Pyramidal tract signs (e.g. brisk knee reflexes, positive Babinski sign, absent ankle reflexes) are initially associated but regress as disease stabilizes (~10 years after onset).
Definition from the Mondo Disease Ontology (MONDO:0011585), read 2026-09-29. CC BY 4.0.
- Inheritance
- Autosomal recessive inheritance
- Onset and course
- Juvenile onset · Progressive
HPO, annotations 2026-09-02
Features
10 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.
- Absent Achilles reflexHPOHP:0003438
- 3 of 3 reported patients
- Decreased compound muscle action potential amplitudeHPOHP:0033383
- 1 of 1 reported patient
- Decreased motor nerve conduction velocityHPOHP:0003431
- 1 of 1 reported patient
- Distal amyotrophyHPOHP:0003693
- 3 of 3 reported patients
- Distal muscle weaknessHPOHP:0002460
- 3 of 3 reported patients
- Foot dorsiflexor weaknessHPO
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.
- SIGMAR1HGNC:8157
- Strong · Labcorp Genetics (formerly Invitae) · Autosomal recessive · 2020
- Supportive · Orphanet · Autosomal recessive · 2021
Where it sits
Other names
4 names
Resolves to: autosomal recessive distal spinal muscular atrophy 2
- Also called
- autosomal recessive distal spinal muscular atrophy type 2dHMNJDSMA2spinal muscular atrophy, distal, autosomal recessive, type 2