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Start free with EleplanProximal spinal muscular atrophy type 3
ORPHA:83419Clinical subtype
Also called Juvenile spinal muscular atrophy · Kugelberg-Welander disease · SMA type 3 · SMA type III · SMA-III · SMA3
What it is
A rare genetic motor neuron disorder characterized by degeneration of alpha motor neurons in the spinal cord and lower brainstem manifesting between 18 months and 18 years of age and associated with slowly progressive, predominantly proximal muscle weakness. By definition, individuals with proximal spinal muscular atrophy (SMA) type 3 achieve independent ambulation before symptom onset, but ambulation may be lost over the course of the disease.
Key facts
- Prevalence
- 1-9 / 1 000 000 (Europe)
- Age of onset
- Adolescent, Adult, Childhood, Infancy
- Inheritance
- Autosomal recessive
- Classified as
- Clinical subtype
Prevalence figures describe populations, not individuals, and are often estimates from a single study. Where the figure is an incidence or a birth prevalence, it says so.
Genes
2 modifying genes — variants that can change how the disease behaves, not cause it
ICD-10 codes
ICD-10 has no distinct code for most rare diseases, so many are filed under the nearest available one. A shared code identifies the group, not this disease — the ORPHAcode above is what identifies it.
Related health topics
Reached through the ICD-10 categories this disease is filed under, so these describe the broader group rather than this disease specifically.
Benefit programs to look at
Programs whose eligibility touches the same ICD-10 categories. Eligibility is decided by the administering agency, never by this page.
Cross-references
Orphadata Science: Free access data from Orphanet. © INSERM 1999. Data version 2026-06-23. Available under CC BY 4.0. This is a reference, not medical advice.
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