Variations in the Mutational Spectrum in Nonsyndromic Hearing Impairment: A study of the Special Schools for the Deaf in Southern China

J Int Adv Otol. 2019 Aug;15(2):247-252. doi: 10.5152/iao.2019.6512.


Objectives: To explore the characteristics of variations in patients with nonsyndromic hearing impairment (NSHI) in Southern China to supply a theoretical basis for screening, intervention, and prevention.

Materials and methods: A total of 634 hearing-impaired students from the special schools for the deaf and 220 normal-hearing individuals in South China were tested using an allele-specific polymerase chain reaction-based universal array, and the screened SLC26A4 mutation carrier was examined using computed tomography. The pathogenesis of deafness was analyzed using pathography and objective hearing tests.

Results: In total, 151 patients with NSHI carried pathogenic mutations in the screening chip, and the carrier rate was 23.82% (151/634) in the studied population. Of the 151 screened carriers, 65 (10.25%) patients harbored homozygous or homoplasmy mutated genes associated with autosomal recessive hearing loss; 36 (5.68%) patients with mutant alleles were homozygous for the GJB2 c.235delC mutation and 27 (4.26%) were heterozygous. Furthermore, 18 (2.84%) patients were homozygous with mutant alleles for the SLC26A4 c.919-2A>G mutation and 43 (6.78%) were heterozygous; 7 (1.10%) patients were homoplasmy mutation carriers of MT-RNR1 gene. There was 1 SLC26A4 c.919-2A>G and 1 GJB2 c.235delC heterozygous mutant allele in the group of 220 normal-hearing individuals.

Conclusion: GJB2 and SLC26A4 were much more prevalent than MT-RNR1 and GJB3 in South China according to this gene chip. Minuscule differences in the mutation spectrum or prevalence of GJB2 c.235delC and SLC26A4 c.919-2A>G were found in our study; furthermore, a relatively high incidence of variations was observed among these individuals with NSHI.

Publication types

  • Multicenter Study

MeSH terms

  • Adolescent
  • Case-Control Studies
  • Child
  • China / ethnology
  • Connexin 26
  • Connexins / genetics
  • Deafness / genetics*
  • Female
  • Heterozygote
  • Homozygote
  • Humans
  • Male
  • Mutation / genetics*
  • Oligonucleotide Array Sequence Analysis
  • RNA, Mitochondrial / genetics
  • RNA, Ribosomal / genetics
  • Sulfate Transporters / genetics
  • Tomography, X-Ray Computed
  • Young Adult


  • Connexins
  • GJB2 protein, human
  • RNA, Mitochondrial
  • RNA, Ribosomal
  • RNA, ribosomal, 12S
  • SLC26A4 protein, human
  • Sulfate Transporters
  • Connexin 26
  • GJB3 protein, human

Supplementary concepts

  • Nonsyndromic Deafness