Variable Phenotypic Expression and Onset in MYH14 Distal Hereditary Motor Neuropathy Phenotype in a Large, Multigenerational North American Family

Muscle Nerve. 2017 Aug;56(2):341-345. doi: 10.1002/mus.25491. Epub 2017 Feb 20.

Abstract

Introduction: Distal hereditary motor neuropathy (dHMN) causes distal-predominant weakness without prominent sensory loss. Myosin heavy chain disorders most commonly result in distal myopathy and cardiomyopathy with or without hearing loss, but a complex phenotype with dHMN, myopathy, hoarseness, and hearing loss was reported in a Korean family with a c.2822G>T mutation in MYH14. In this study we report phenotypic features in a North American family with the c.2822G>T in MYH14.

Methods: Clinical and molecular characterization was performed in a large, 6-generation, Caucasian family with MYH14 dHMN.

Results: A total of 11 affected and 7 unaffected individuals were evaluated and showed varying age of onset and severity of weakness. Genotypic concordance was confirmed with molecular analysis. Electrophysiological studies demonstrated distal motor axonal degeneration without myopathy in all affected subjects tested.

Conclusion: Mutation of MYH14 can result in a range of neuromuscular phenotypes that includes a dHMN and hearing loss phenotype with variable age of onset. Muscle Nerve 56: 341-345, 2017.

Keywords: autosomal dominant; distal hereditary motor neuropathy; hearing loss; myopathy; myosin.

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • Action Potentials / genetics
  • Adult
  • Family Health*
  • Female
  • Genetic Linkage
  • Genotype
  • Hereditary Sensory and Motor Neuropathy / genetics*
  • Hereditary Sensory and Motor Neuropathy / physiopathology
  • Humans
  • Male
  • Middle Aged
  • Muscle, Skeletal / physiology
  • Muscle, Skeletal / physiopathology
  • Myosin Heavy Chains / genetics*
  • Myosin Type II / genetics*
  • North America / epidemiology
  • Phenotype

Substances

  • MYH14 protein, human
  • Myosin Type II
  • Myosin Heavy Chains