Genetic heterogeneity in GJB2, COL4A3, ATP6V1B1 and EDNRB variants detected among hearing impaired families in Morocco

Mol Biol Rep. 2022 May;49(5):3949-3954. doi: 10.1007/s11033-022-07245-z. Epub 2022 Mar 17.

Abstract

Background: Deafness is the most prevalent human sensorineural defect. It may occur as a result of an external auditory canal involvement, or a deficiency in the sound conduction mechanism, or an impairment of the cochlea, the cochlear nerve or central auditory perception. The genetic causes are the most common, as approximately 70% of hearing disorders are of hereditary origin, divided into two groups, syndromic (associated with other symptoms) and no syndromic (isolated deafness).

Methods: A whole exome sequencing was performed to identify the genetic cause of hearing loss in six Moroccan families and Sanger sequencing was used to validate mutations in these genes.

The results: The results of four out of the six families revealed four genetic variants in the genes GJB2, COL4A3, ATP6V1B1 and EDNRB responsible for non-syndromic and syndromic hearing loss. Multiple Bioinformatics programs and molecular modelling predicted the pathogenic effect of these mutations.

Conclusions: We identified in Moroccan deaf patients four homozygous mutations. These results show the importance of whole exome sequencing to identify pathogenic mutations in heterogeneous disorders with multiple genes responsible.

Keywords: Hearing loss; Moroccan patients; Mutation; Whole exome sequencing.

MeSH terms

  • Autoantigens* / genetics
  • Collagen Type IV* / genetics
  • Connexin 26* / genetics
  • Connexins / genetics
  • Deafness / genetics
  • Genetic Heterogeneity
  • Hearing
  • Hearing Loss* / genetics
  • Hearing Loss, Sensorineural* / genetics
  • Humans
  • Morocco
  • Mutation
  • Pedigree
  • Receptor, Endothelin B* / genetics
  • Vacuolar Proton-Translocating ATPases* / genetics

Substances

  • ATP6V1B1 protein, human
  • Autoantigens
  • Collagen Type IV
  • Connexins
  • EDNRB protein, human
  • GJB2 protein, human
  • Receptor, Endothelin B
  • type IV collagen alpha3 chain
  • Connexin 26
  • Vacuolar Proton-Translocating ATPases