Reducing body myopathy associated with the LIM2 p.(His123Arg) FHL1 variant

Clin Neurol Neurosurg. 2021 Aug:207:106795. doi: 10.1016/j.clineuro.2021.106795. Epub 2021 Jul 7.

Abstract

Reducing body myopathy (RBM) is a rare muscle disorder, with marked presence of characteristic intracytoplasmic aggregates in affected muscle fibers. RBM is associated with FHL1 gene mutations. Clinical presentations of RBM have ranged from early fatal to adult onset progressive muscle weakness. We present herein the clinical, electrodiagnostic, and muscle biopsy findings of a 17-year-old female with progressive muscle weakness and contracture. Muscle biopsy showed atrophic fibers that contained menadione nitroblue tetrazolium (NBT) positive reducing bodies. Genetic testing revealed a variant of uncertain significance in the FHL1 gene at a position known to be pathogenic when substituted by other amino acids (p.His123Arg). This variant was later reclassified as pathogenic.

Keywords: FHL1; Muscle weakness; Myopathy; RBM; Reducing body.

Publication types

  • Case Reports

MeSH terms

  • Adolescent
  • Female
  • Humans
  • Inclusion Bodies / genetics
  • Inclusion Bodies / pathology
  • Intracellular Signaling Peptides and Proteins / genetics*
  • LIM Domain Proteins / genetics*
  • Muscle Proteins / genetics*
  • Muscular Diseases / genetics*
  • Muscular Diseases / pathology*
  • Mutation

Substances

  • FHL1 protein, human
  • Intracellular Signaling Peptides and Proteins
  • LIM Domain Proteins
  • Muscle Proteins