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Determining the Likelihood of Variant Pathogenicity Using Amino Acid-level Signal-to-Noise Analysis of Genetic Variation
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Three novel MTM1 pathogenic variants identified in Japanese patients with X-linked myotubular myopathy

Atsuko Nishikawa1, Aritoshi Iida2, Shinichiro Hayashi1

  • 1Department of Neuromuscular Research, National Institute of Neuroscience, National Center of Neurology and Psychiatry, Tokyo, Japan.

Molecular Genetics & Genomic Medicine
|March 19, 2019
PubMed
Abstract

Insights

X-linked myotubular myopathy (XLMTM), a severe congenital muscle disease, is caused by MTM1 gene mutations. Novel variants in male infants reveal distinct pathological features, offering insights into disease variations.

Area of Science:

  • Genetics
  • Neuromuscular Disorders
  • Molecular Biology

Background:

  • X-linked myotubular myopathy (XLMTM) is a severe congenital muscle disease affecting male infants.
  • Characterized by profound muscle weakness, hypotonia, and challenges with feeding and breathing.
  • Caused by mutations in the myotubularin gene (MTM1).

Observation:

  • Three male infants with distinct muscle pathological features were studied.
  • Comprehensive genome analysis was performed using a targeted gene panel system.
  • Clinical history and muscle pathology were evaluated.

Findings:

  • Three novel hemizygous MTM1 variants (c.527A>G, c.595C>G, c.688T>C) were identified.
  • These variants were classified as Class 4 (likely pathogenic) according to ACMG guidelines.
  • Patients exhibited distinct muscle pathological features despite MTM1 variants.

Implications:

  • The identified MTM1 variants provide new genetic insights into XLMTM.
  • Distinct pathological features associated with MTM1 variants suggest microheterogeneity in disease presentation.
  • Findings contribute to understanding the spectrum of XLMTM phenotypes.
Keywords:
MTM1X-linked myotubular myopathynovel variantstargeted gene panel system

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