Expanding the genotypic spectrum of ACTG2-related visceral myopathy

Cold Spring Harb Mol Case Stud. 2021 Jun 11;7(3):a006085. doi: 10.1101/mcs.a006085. Print 2021 Jun.

Abstract

Visceral myopathies (VMs) encompass a spectrum of disorders characterized by chronic disruption of gastrointestinal function, with or without urinary system involvement. Pathogenic missense variation in smooth muscle γ-actin gene (ACTG2) is associated with autosomal dominant VM. Whole-genome sequencing of an infant presenting with chronic intestinal pseudo-obstruction revealed a homozygous 187 bp (c.589_613 + 163del188) deletion spanning the exon 6-intron 6 boundary within ACTG2 The patient's clinical course was marked by prolonged hospitalizations, multiple surgeries, and intermittent total parenteral nutrition dependence. This case supports the emerging understanding of allelic heterogeneity in ACTG2-related VM, in which both biallelic and monoallelic variants in ACTG2 are associated with gastrointestinal dysfunction of similar severity and overlapped clinical presentation. Moreover, it illustrates the clinical utility of rapid whole-genome sequencing, which can comprehensively and precisely detect different types of genomic variants including small deletions, leading to guidance of clinical care decisions.

Keywords: chronic constipation; hypoperistalsis; ileus; intestinal pseudo-obstruction.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Actins / genetics*
  • Genotype*
  • Humans
  • Ileus
  • Infant
  • Intestinal Pseudo-Obstruction / diagnosis*
  • Intestinal Pseudo-Obstruction / genetics*
  • Intestinal Pseudo-Obstruction / pathology
  • Male
  • Pedigree
  • Treatment Outcome
  • Whole Genome Sequencing

Substances

  • ACTG2 protein, human
  • Actins