Compound Heterozygous MYO7A Mutations Segregating Usher Syndrome Type 2 in a Han Family

Int J Pediatr Otorhinolaryngol. 2016 Nov;90:150-155. doi: 10.1016/j.ijporl.2016.09.010. Epub 2016 Sep 12.

Abstract

Objective: Identification of rare deafness genes for inherited congenital sensorineural hearing impairment remains difficult, because a large variety of genes are implicated. In this study we applied targeted capture and next-generation sequencing to uncover the underlying gene in a three-generation Han family segregating recessive inherited hearing loss and retinitis pigmentosa.

Methods: After excluding mutations in common deafness genes GJB2, SLC26A4 and the mitochondrial gene, genomic DNA of the proband of a Han family was subjected to targeted next-generation sequencing. The candidate mutations were confirmed by Sanger sequencing and subsequently analyzed with in silico tools.

Results: An unreported splice site mutation c.3924+1G > C compound with c.6028G > A in the MYO7A gene were detected to cosegregate with the phenotype in this pedigree. Both mutations, located in the evolutionarily conserved FERM domain in myosin VIIA, were predicted to be pathogenic. In this family, profound sensorineural hearing impairment and retinitis pigmentosa without vestibular disorder, constituted the typical Usher syndrome type 2.

Conclusion: Identification of novel mutation in compound heterozygosity in MYO7A gene revealed the genetic origin of Usher syndrome type 2 in this Han family.

Keywords: Hearing; MYO7A; Nonsense-mediated mRNA decay; Targeted next-generation sequencing; Usher syndrome.

MeSH terms

  • Adolescent
  • Adult
  • Asian Continental Ancestry Group / genetics*
  • Child
  • DNA Mutational Analysis
  • Family*
  • Female
  • Heterozygote
  • High-Throughput Nucleotide Sequencing
  • Humans
  • Male
  • Middle Aged
  • Mutation
  • Myosin VIIa
  • Myosins / genetics*
  • Pedigree
  • Phenotype
  • Usher Syndromes / genetics*
  • Young Adult

Substances

  • MYO7A protein, human
  • Myosin VIIa
  • Myosins