Increasing involvement of CAPN1 variants in spastic ataxias and phenotype-genotype correlations

Neurogenetics. 2021 Mar;22(1):71-79. doi: 10.1007/s10048-020-00633-2. Epub 2021 Jan 23.


Spastic ataxias are rare neurogenetic disorders involving spinocerebellar and pyramidal tracts. Many genes are involved. Among them, CAPN1, when mutated, is responsible for a complex inherited form of spastic paraplegia (SPG76). We report the largest published series of 21 novel patients with nine new CAPN1 disease-causing variants and their clinical characteristics from two European university hospitals (Paris and Stockholm). After a formal clinical examination, causative variants were identified by next-generation sequencing and confirmed by Sanger sequencing. CAPN1 variants are a rare cause (~ 1.4%) of young-adult-onset spastic ataxia; however, together with all published cases, they allowed us to better describe the clinical and genetic spectra of this form. Truncating variants are the most frequent, and missense variants lead to earlier age at onset in favor of an additional deleterious effect. Cerebellar ataxia with cerebellar atrophy, dysarthria and lower limb weakness are often associated with spasticity. We also suggest that cognitive impairment and depression should be assessed specifically in the follow-up of SPG76 cases.

Keywords: CAPN1; Cerebellar ataxia; Neurodegeneration; Spastic ataxia; Spastic paraplegia.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Age of Onset
  • Calpain / genetics*
  • Cerebellar Ataxia / genetics
  • Child
  • Female
  • Genetic Association Studies
  • Humans
  • Intellectual Disability / diagnosis
  • Intellectual Disability / genetics*
  • Male
  • Muscle Spasticity / diagnosis
  • Muscle Spasticity / genetics*
  • Mutation / genetics*
  • Optic Atrophy / diagnosis
  • Optic Atrophy / genetics*
  • Pedigree
  • Phenotype
  • Spastic Paraplegia, Hereditary / genetics*
  • Spinocerebellar Ataxias / diagnosis
  • Spinocerebellar Ataxias / genetics*
  • Young Adult


  • Calpain
  • CAPN1 protein, human

Supplementary concepts

  • Spastic Ataxia