Molecular analysis of the GJB2, GJB6 and SLC26A4 genes in Korean deafness patients.
OBJECTIVE
Mutations in the GJB2, GJB6 and SLC26A4 genes are a frequent cause of hearing loss in a number of populations. However, little is known about the genetic causes of hearing loss in the Korean population.


METHODS
We sequenced the GJB2 and GJB6 genes to examine the role of mutations in these genes in 22 hearing loss patients. We also sequenced the SLC26A4 gene in seven patients with inner ear malformations, including enlarged vestibular aqueduct (EVA) revealed by computer tomography.


RESULTS
Coding sequence mutations in GJB2 were identified in 13.6% of the patients screened. Two different mutations, 235delC and T86R were found in three unrelated patients. The 235delC was the most prevalent mutation with an allele frequency of 6.9% in our patient group. No mutations, including 342-kb deletion, were found in GJB6 gene. Three different variants of SLC26A4 were identified in the EVA patients, including one novel mutation. Four EVA patients carried two mutant alleles of SLC26A4, and at least one allele in all patients was the H723R mutation, which accounted for 75% of all mutant alleles.


CONCLUSIONS
Our results suggest that GJB2 and SLC26A4 mutations together make up a major cause of congenital hearing loss in the Korean population. Further studies may be able to identify other common variants that account for a significant fraction of hearing loss in the Korean population.
Lee
K Y
KY
Department of Otolaryngology, College of Medicine, Kyungpook National University, Deagu 702-701, Republic of Korea.
Choi
S Y
SY
Bae
J W
JW
Kim
S
S
Chung
K W
KW
Drayna
D
D
Kim
U K
UK
Lee
S H
SH
D000293:Adolescent; D000328:Adult; D000595:Amino Acid Sequence; D044466:Asian People; D002648:Child; D002675:Child, Preschool; D000072259:Connexin 26; D000075302:Connexin 30; D017630:Connexins / Q000235:genetics*; D003638:Deafness / Q000235:genetics*; D005260:Female; D006801:Humans; D007723:Korea; D008297:Male; D026901:Membrane Transport Proteins / Q000235:genetics*; D008875:Middle Aged; D009154:Mutation; D000076988:Sulfate Transporters; D055815:Young Adult
D000075302:Connexin 30; D017630:Connexins; C000607042:GJB2 protein, human; C491020:GJB6 protein, human; D026901:Membrane Transport Proteins; C085609:SLC26A4 protein, human; D000076988:Sulfate Transporters; D000072259:Connexin 26