Background: Nonsyndromic hearing loss is clinically and genetically heterogeneous. In this study, we characterized the clinical features of 12 Chinese Han deaf families in which mutations in common deafness genes GJB2, SLC26A4, and MT-RNR1 were excluded. Methods: Targeted next-generation sequencing of 147 known deafness genes was performed in probands of 10 families, while whole-exome sequencing was applied in those of the rest two. Results: Pathogenic mutations in a total of 11 rare deafness genes, OTOF, CDH23, PCDH15, PDZD7, ADGRV1, KARS, OTOG, GRXCR2, MYO6, GRHL2, and POU3F4, were identified in all 12 probands, with 16 mutations being novel.Intrafamilial cosegregation of the mutations and the deafness phenotype were confirmed by Sanger sequencing. Conclusion: Our results expanded the mutation spectrum and genotype-phenotype correlation of nonsyndromic hearing loss in Chinese Hans and also emphasized the importance of combining both next-generation sequencing and detailed auditory evaluation to achieve a more accurate diagnosis for nonsyndromic hearing loss. K E Y W O R D Sdeafness, gene mutation, next-generation sequencing (NGS), nonsyndromic, phenotype

BACKGROUND: Non-syndromic hearing loss is clinically and genetically heterogeneous. In this study, we characterized the clinical features of twelve Chinese Han deaf families in which mutations in common deafness genes GJB2 , SLC26A4 and MT-RNR1 were excluded. RESULTS: Targeted next-generation sequencing of 147 known deafness genes was performed in probands of ten families, while whole-exome sequencing was applied in those of the rest two. Pathogenic mutations in a total of 11 rare deafness genes, OTOF , CDH23 , PCDH15 , PDZD7 , ADGRV1 , KARS , OTOG , GRXCR2 , MYO6 , GRHL2 , and POU3F4 , were identified in all 12 probands, with 17 mutations being novel. Intrafamilial co-segregation of the mutations and the deafness phenotype were confirmed by Sanger sequencing. CONCLUSIONS: Our results expanded the mutation spectrum and genotype-phenotype correlation of non-syndromic hearing loss in Chinese Hans and also emphasized the importance of combining both next-generation sequencing and detailed auditory evaluation to achieve a more accurate diagnosis for non-syndromic hearing loss.