Novel mitochondrial gene variants in Northwestern Chinese probands with non-syndromic hearing loss by whole mitochondrial genome screening.

Mitochondrial DNA mutations play an important role in hereditary hearing loss. The present study aimed at identifying more novel genetic variants of mitochondrial DNA. Complete Mitochondrial genomes were detected in 97 Northwestern Chinese probands with non-syndromic hearing loss and 376 control subjects. The variants were evaluated for the pathogenicity using the following criteria: (1) present in <1% of the controls, (2) evolutional conservation, (3) potential structural and functional alterations. Mutational analysis in probands identified 706 variants, including 180 variants in the D loop region, 27 variants in the 12S rRNA gene, 29 variants in the 16S rRNA gene, 122 missense variants and 312 silent variants in the protein coding gene, 29 variants in the tRNA genes and 7 variants in the non-coding region. After further analysis assessed for the potential structural and functional significance, we identified 5 new candidate variants for hearing loss: 12S rRNA1473C>T, tRNAPhe 614A>C, tRNALys 8339A>G, ND1 3866T>C and non-coding 5656A>G. Our findings may provide the role of these genes in hearing loss development in China and valuable information for the further understanding of pathogenic mechanism of hearing loss.