Charcot-Marie-Tooth disease type 1C: Clinical and electrophysiological findings for the c.334G>a (p.Gly112Ser) Litaf/Simple mutation

Muscle Nerve. 2017 Dec;56(6):1092-1095. doi: 10.1002/mus.25600. Epub 2017 Apr 29.

Abstract

Introduction: Charcot-Marie-Tooth disease type 1C (CMT1C) is a rare, dominantly inherited neuropathy caused by mutations in the lipopolysaccharide-induced tumor necrosis factor (LITAF) or small integral membrane protein of the lysosome/late endosome (SIMPLE) gene.

Methods: We present a case series comprised of 10 patients in whom CMT1C is caused by a Gly112Ser substitution in the encoded protein. We focus on clinical presentation, electrodiagnostic analyses, and our findings in the context of previously described cases.

Results: The Gly112Ser mutation causing CMT1C is a mild form of CMT, as patients walked on time, had less weakness than those with Charcot-Marie-Tooth disease type 1A (CMT1A), had a CMT neuropathy score (CMTNS) indicative of mild disease, and had faster ulnar and median motor nerve conduction velocities compared to those with CMT1A.

Discussion: The G112S mutation in LITAF seems to be clinically indistinguishable from a mild presentation of CMT1A. Muscle Nerve 56: 1092-1095, 2017.

Keywords: CMT1C; EDx; HMSN type 1; LITAF; SIMPLE; nerve conduction studies.

MeSH terms

  • Adolescent
  • Adult
  • Aged
  • Charcot-Marie-Tooth Disease / diagnosis
  • Charcot-Marie-Tooth Disease / genetics*
  • Charcot-Marie-Tooth Disease / physiopathology*
  • Child
  • Child, Preschool
  • Electrophysiological Phenomena / physiology
  • Female
  • Glycine / genetics*
  • Humans
  • Male
  • Middle Aged
  • Mutation / genetics*
  • Nuclear Proteins / genetics*
  • Retrospective Studies
  • Serine / genetics*
  • Transcription Factors / genetics*
  • Young Adult

Substances

  • LITAF protein, human
  • Nuclear Proteins
  • Transcription Factors
  • Serine
  • Glycine

Supplementary concepts

  • Charcot-Marie-Tooth disease, Type 1C