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This information is for you, if you or your child have been recently diagnosed with DSMA-V.

The first symptom is often cramps in the hand brought on by exposure to cold temperatures. Symptoms usually begin during adolescence, but onset varies from infancy to the mid-thirties.

Over time this first symptom is followed by weakness and wasting (atrophy) of hand muscles, specifically on the thumb-side of the index finger and in the palm at the base of the thumb. It is also common to have a high foot arch, and some people develop difficulties with walking.

People with this condition have a normal life expectancy.

DSMA-V has been linked to mutations in several different genes:

  • BSCL21-2 – Further information can be found here.
  • GARS13-4 – Further information can be found here.
  • REEP15-6 – Further information can be found here.

Based on the gene that causes the condition, DSMA-V is sometimes subdivided into DSMA-VA (GARS1), DSMA-VB (REEP1) and DSMA-VC (BSCL2).

Some of the genes that cause rarer forms of SMA are associated with more than one condition, so please be aware that the website links provided may also give information about other conditions.

DSMA-V has an autosomal dominant inheritance pattern, which means that only one faulty gene copy passed on from a parent with the condition will cause the condition.

To find out more about this form of inheritance, please see our information giude: The inheritance patterns of some rarer forms of SMA.

Though not a substitute for professional medical advice, the US National Library of Medicine, Genetics Home Reference provides more information. Click here to read more.


Provides information and support for anyone in the UK affected by any form of SMA.


Provides information and support for families with children with a disability.

  1. Windpassinger et al. (2004) Heterozygous missense mutations in BSCL2 are associated with distal hereditary motor neuropathy and Silver syndrome. Nat Genetics 36: 271-276.
  2. (last accessed 16th August 2022)
  3. Antonellis et al. (2003) Glycyl tRNA synthetase mutations in Charcot-Marie-Tooth disease type 2D and distal spinal muscular atrophy type V. Am J Hum Genet 72: 1293-1299.
  4. (last accessed 16th August 2022)
  5. Beetz et al. (2012) Exome sequencing identifies a REEP1 mutation involved in distal hereditary motor neuropathy type V. Am J Hum Genet 91: 139-145.
  6. (last accessed 16th August 2022)

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Author: SMA UK Information Production Team
Last updated: August 2022
Next full review due September 2024

Links last checked: September 2023

The information provided in this guide, on our website, and through links to other websites, is designed to complement not be a substitute for clinical and professional care and advice.

For more detail about how we produce our information, please see these pages.

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