A novel variant in the CDH23 gene is associated with non-syndromic hearing loss in a Chinese family

To explore the pathogenic causes of a proband who was diagnosed with non-syndromic hearing loss. We performed targeted capture of 159 known deafness-related genes and next-generation sequencing in the proband who was tested negative for the twenty hotspot variants in four common deafness-related genes(GJB2, GJB3, SLC26A4 and MTRNR1); Clinical reassessments, including detailed audiological and ocular examinations were performed in the proband and his normal parents. We identified a novel heterozygous variant of CDH23:c.4567A > G (p.Asn1523Asp) in exon 37 (NM_022124), in conjunction with a reported mutation of CDH23:c.5101G > A (p.Glu1701Lys) in exon 40, to be a potentially pathogenic compound heterozygosity in the proband. The unaffected father has a heterozygous variant of CDH23:c.4567A > G, and the normal mother has another heterozygous variant, CDH23:c.5101G > A. The novel variant was absent in the 1000 Genomes Project. The clinical reassessments revealed binaural profound sensorineural hearing loss (DFNB12) without retinitis pigmentosa in the proband. This study demonstrates that the novel variant c.4567A > G (p.Asn1523Asp) in compound heterozygosity with c.5101G > A (p. Glu1701Lys) in the CDH23 gene is the main cause of DFNB12 in the proband. Simultaneously, this study provides a foundation to further elucidate the CDH23-related mechanisms of DFNB12.