Identification of CDH23 mutations in Korean families with hearing loss by whole-exome sequencing.
BACKGROUND
Patient genetic heterogeneity renders it difficult to discover disease-cause genes. Whole-exome sequencing is a powerful new strategy that can be used to this end. The purpose of the present study was to identify a hitherto unknown mutation causing autosomal recessive nonsyndromic hearing loss (ARNSHL) in Korean families.


METHODS
We performed whole-exome sequencing in 16 individuals from 13 unrelated small families with ARNSHL. After filtering out population-specific polymorphisms, we focused on known deafness genes. Pathogenic effects of the detected mutations on protein structure or function were predicted via in silico analysis.


RESULTS
We identified compound heterozygous CDH23 mutations in hearing-loss genes of two families. These include two previously reported pathological mutations, p.Pro240Leu and p.Glu1595Lys, as well as one novel mutation, p.Asn342Ser. The p.Pro240Leu mutation was found in both families. We also identified 26 non-synonymous variants in CDH23 coding exons from 16 hearing-loss patients and 30 Korean exomes.


CONCLUSIONS
The present study is the first to show that CDH23 mutations cause hearing loss in Koreans. Although the precise contribution made by such mutations needs to be determined using a larger patient cohort, our data indicate that mutations in the CDH23 gene are one of the most important causes of non-syndromic hearing loss in East Asians. Further exome sequencing will identify common mutations or polymorphisms and contribute to the molecular diagnosis of, and development of new therapies for, hereditary hearing loss.
Hae-Mi
HM
Woo
Hong-Joon
HJ
Park
Mi-Hyun
MH
Park
Bo-Young
BY
Kim
Joong-Wook
JW
Shin
Won Gi
WG
Yoo
Division of Intractable Diseases, Center for Biomedical Sciences, National Institute of Health, Chungcheongbuk-do 363-951, South Korea. skkoo@nih.go.kr.
Soo Kyung
SK
Koo
D000595:Amino Acid Sequence; D044466:Asian People / Q000235:genetics*; D001299:Audiometry; D000070585:Cadherin Related Proteins; D015820:Cadherins / Q000737:chemistry / Q000235:genetics*; D002675:Child, Preschool; D004252:DNA Mutational Analysis; D059472:Exome; D005091:Exons; D005260:Female; D034381:Hearing Loss / Q000175:diagnosis / Q000235:genetics*; D059014:High-Throughput Nucleotide Sequencing; D006801:Humans; D007223:Infant; D008297:Male; D008958:Models, Molecular; D008969:Molecular Sequence Data; D009154:Mutation; D009218:Myosins / Q000235:genetics; D010375:Pedigree; D011110:Polymorphism, Genetic; D011487:Protein Conformation; D054730:Protein Interaction Domains and Motifs; D056910:Republic of Korea; D016415:Sequence Alignment
C442480:CDH23 protein, human; D000070585:Cadherin Related Proteins; D015820:Cadherins; C485245:MYO15A protein, human; D009218:Myosins