Objectives: Mutations in MT-TS1 have been found to be associated with nonsyndromic sensorineural hearing loss (SNHL). PCDH15 codes for protocadherin-15, a member of the cadherin superfamily of calcium-dependent cell-cell adhesion molecules. In this study, we analyzed the correlation of both MT-TS1 and PCDH15 mutations in a Chinese Han family segregating maternally inherited nonsyndromic SNHL.
Methods: We ascertained a Chinese Han family segregating maternally inherited nonsyndromic sensorineural hearing loss. Eight of 10 maternal members in this family exhibited late-onset, progressive hearing impairment. Mutation screening of 79 known deafness genes was performed for the proband by targeted next-generation sequencing.
Results: A total of 651 variants were detected in this individual. Among them, a homoplasmic 7511T>C variant in MT-TS1, the mitochondrial tRNA (Ser(UCN)) gene, and a heterozygous p.Asp1010Gly variant in PCDH15 were more likely to be pathogenic. Consistent with the matrilineal inheritance with reduced penetrance, the 7511T>C variant in MT-TS1 was found in all 10 maternal members and an additional heterozygous p.Asp1010Gly variant in PCDH15 cosegregated with the hearing loss in this family.
Conclusion: Our results suggested that the PCDH15 p.Asp1010Gly variant probably modified the phenotypic expression of the 7511T>C mutation in MT-TS1.
Keywords: Hearing loss; Mitochondria; Modifier; Mutation.
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