SLC26A4 c.919-2A>G varies among Chinese ethnic groups as a cause of hearing loss.
OBJECTIVE
Mutations in the SLC26A4 gene are second only to GJB2 mutations as a currently identifiable genetic cause of sensorineural hearing loss. In most areas of China, genetic testing for sensorineural hearing loss is unavailable because of limited knowledge of the mutation spectrum. Although SLC26A4 c.919-2A>G (IVS7-2A>G) is a common mutation among some Asian populations, the mutation prevalence among various ethnic groups within China has not been studied.


METHODS
DNA specimens from 3271 subjects with moderate to profound sensorineural hearing loss from 27 regions of China were genotyped for the c.919-2A>G mutation by polymerase chain reaction/restriction-fragment-length polymorphism. Normal hearing controls from Han (n = 185) and Uigur (n = 152) populations were also tested.


RESULTS
Overall, 408 subjects with sensorineural hearing loss (12.5%) carried at least one c.919-2A>G allele, with 158 (4.8%) homozygotes and 250 (7.6%) heterozygotes. Within the subpopulations examined, the rate varies from 0% to 12.2% for c.919-2A>G homozygotes and from 0% to 17.6% for heterozygotes. Based on this cohort, Chinese subjects with sensorineural hearing loss seem to have a relatively higher c.919-2A>G frequency than that of other Asian populations.


CONCLUSIONS
These results demonstrate that a simple and efficient genetic test for the c.919-2A>G mutation alone would identify the molecular cause in up to 8-12% of individuals with sensorineural hearing loss in a few eastern and central regions of China. Those who are negative for the c.919-2A>G mutation would be candidates for further mutational analysis of SLC26A4 or other deafness-related genes. This would greatly improve genetic diagnosis and counseling for a huge number of Chinese individuals and family members with sensorineural hearing loss in China, and many more ethnic Chinese in other countries, which might be up to one million.
Dai
Pu
P
Department of Otolaryngology and Genetic Testing Center for Deafness, Chinese PLA General Hospital, Beijing, People's Republic of China.
Li
Qi
Q
Huang
Deliang
D
Yuan
Yongyi
Y
Kang
Dongyang
D
Miller
David T
DT
Shao
Hong
H
Zhu
Qingwen
Q
He
Jia
J
Yu
Fei
F
Liu
Xin
X
Han
Bing
B
Yuan
Huijun
H
Platt
Orah S
OS
Han
Dongyi
D
Wu
Bai-Lin
BL
D000293:Adolescent; D044466:Asian People / Q000235:genetics*; D002648:Child; D002675:Child, Preschool; D002681:China / Q000453:epidemiology / Q000208:ethnology; D000072259:Connexin 26; D017630:Connexins; D005260:Female; D005787:Gene Frequency; D014644:Genetic Variation; D005843:Geography; D006319:Hearing Loss, Sensorineural / Q000453:epidemiology / Q000208:ethnology* / Q000235:genetics*; D006801:Humans; D008297:Male; D026901:Membrane Transport Proteins / Q000235:genetics*; D009154:Mutation / Q000235:genetics*; D015995:Prevalence; D000076988:Sulfate Transporters; D055815:Young Adult
D017630:Connexins; C000607042:GJB2 protein, human; D026901:Membrane Transport Proteins; C085609:SLC26A4 protein, human; D000076988:Sulfate Transporters; D000072259:Connexin 26