Autosomal dominant spinal muscular atrophy with lower extremity predominance: A recognizable phenotype of BICD2 mutations

Muscle Nerve. 2016 Sep;54(3):496-500. doi: 10.1002/mus.25114. Epub 2016 Jul 9.

Abstract

Introduction: Heterozygous BICD2 gene mutations cause a form of autosomal dominant spinal muscular atrophy with lower extremity predominance (SMALED).

Methods: We analyzed the BICD2 gene in a selected group of 25 index patients with neurogenic muscle atrophy.

Results: We identified 2 new BICD2 missense mutations, c.2515G>A, p.Gly839Arg, in a family with autosomal dominant inheritance, and c.2202G>T, p.Lys734Asn, as a de novo mutation in an isolated patient with similar phenotype. The patients had congenital foot contractures, muscle atrophy of the legs, and slowly progressive weakness of the shoulder girdle. There was no apparent sensory or brain dysfunction. One patient died of unrelated reasons at age 52 years. Autopsy revealed no upper motor neuron and only moderate lower motor neuron loss, but there was distal corticospinal tract degeneration and marked neurogenic muscular atrophy.

Conclusion: These findings give further insight into the clinical and pathoanatomical consequences of BICD2 mutations. Muscle Nerve 54: 496-500, 2016.

Keywords: BICD2 gene; arthrogryposis multiplex congenital; axonopathy; dominant congenital spinal muscular atrophy; lower extremity predominance; spinal muscular atrophy.

Publication types

  • Case Reports
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Aged
  • DNA Mutational Analysis
  • Family Health
  • Female
  • Genes, Dominant / genetics*
  • Genetic Linkage
  • Humans
  • Lower Extremity / physiopathology*
  • Male
  • Microtubule-Associated Proteins / genetics*
  • Middle Aged
  • Muscular Atrophy, Spinal / genetics*
  • Muscular Atrophy, Spinal / pathology*
  • Mutation / genetics*
  • Phenotype

Substances

  • BICD2 protein, human
  • Microtubule-Associated Proteins