Novel Compound Heterozygous Mutation in TRAPPC9 Gene: The Relevance of Whole Genome Sequencing

Genes (Basel). 2021 Apr 12;12(4):557. doi: 10.3390/genes12040557.

Abstract

Advances in high-throughput technologies and its implementation worldwide have had a considerable impact on the elucidation of the molecular causes underlying neurodevelopmental psychiatric disorders, especially for autism spectrum disorder and intellectual disability (ID). Nevertheless, etiology remains elusive in close to 50% of cases, even in those families with multiple affected individuals, strongly hinting at a genetic cause. Here we present a case report of two siblings affected with severe ID and other comorbidities, who embarked on a genetic testing odyssey until diagnosis was reached by using whole genome sequencing (WGS). WGS identified a maternally inherited novel missense variant (NM_031466.7:c.1037G > A; p.Gly346Glu) and a paternally inherited 90 kb intragenic deletion in TRAPPC9 gene. This report demonstrates the clinical utility of WGS in patients who remain undiagnosed after whole exome sequencing.

Keywords: TRAPPC9; compound heterozygous mutations; missense mutation; neurodevelopmental disorders; neuropsychiatric disorders; structural variants; whole genome sequencing.

Publication types

  • Case Reports
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Genetic Predisposition to Disease
  • Heterozygote
  • Humans
  • Intellectual Disability / genetics*
  • Intercellular Signaling Peptides and Proteins / genetics*
  • Male
  • Maternal Inheritance
  • Mutation, Missense*
  • Paternal Inheritance
  • Pedigree
  • Siblings
  • Whole Genome Sequencing / methods*

Substances

  • Intercellular Signaling Peptides and Proteins
  • TRAPPC9 protein, human