KCNJ10 may not be a contributor to nonsyndromic enlargement of vestibular aqueduct (NSEVA) in Chinese subjects.
BACKGROUND
Nonsyndromic enlargement of vestibular aqueduct (NSEVA) is an autosomal recessive hearing loss disorder that is associated with mutations in SLC26A4. However, not all patients with NSEVA carry biallelic mutations in SLC26A4. A recent study proposed that single mutations in both SLC26A4 and KCNJ10 lead to digenic NSEVA. We examined whether KCNJ10 excert a role in the pathogenesis of NSEVA in Chinese patients.


METHODS
SLC26A4 was sequenced in 1056 Chinese patients with NSEVA. KCNJ10 was screened in 131 patients who lacked mutations in either one or both alleles of SLC26A4. Additionally, KCNJ10 was screened in 840 controls, including 563 patients diagnosed with NSEVA who carried biallelic SLC26A4 mutations, 48 patients with nonsyndromic hearing loss due to inner ear malformations that did not involve enlargement of the vestibular aqueduct (EVA), 96 patients with conductive hearing loss due to various causes, and 133 normal-hearing individuals with no family history of hereditary hearing loss.


RESULTS
925 NSEVA patients were found carrying two-allele pathogenic SLC26A4 mutations. The most frequently detected KCNJ10 mutation was c.812G>A (p.R271H). Compared with the normal-hearing control subjects, the occurrence rate of c.812G>A in NSEVA patients with lacking mutations in one or both alleles of SLC26A4 had no significant difference(1.53% vs. 5.30%, χ(2) = 2.798, p = 0.172), which suggested that it is probably a nonpathogenic benign variant. KCNJ10 c.1042C>T (p.R348C), the reported EVA-related mutation, was not found in patients with NSEVA who lacked mutations in either one or both alleles of SLC26A4. Furthermore, the normal-hearing parents of patients with NSEVA having two SLC26A4 mutations carried the KCNJ10 c.1042C>T or c.812G>A mutation and a SLC26A4 pathogenic mutation.


CONCLUSIONS
SLC26A4 is the major genetic cause in Chinese NSEVA patients, accounting for 87.59%. KCNJ10 may not be a contributor to NSEVA in Chinese population. Other genetic or environmental factors are possibly play a role in the etiology of Chinese EVA patients with zero or monoallelic SLC26A4 mutation.
Department of Otolaryngology, PLA General Hospital, Beijing, People's Republic of China.
Jiandong
J
Zhao
Department of Otolaryngology, PLA General Hospital, Beijing, People's Republic of China; Department of Otolaryngology, Hainan Branch of PLA General Hospital, Sanya, People's Republic of China.
Yongyi
Y
Yuan
Department of Otolaryngology, PLA General Hospital, Beijing, People's Republic of China.
Shasha
S
Huang
Department of Otolaryngology, Hainan Branch of PLA General Hospital, Sanya, People's Republic of China.
Bangqing
B
Huang
Department of Otolaryngology, PLA General Hospital, Beijing, People's Republic of China.
Jing
J
Cheng
Department of Otolaryngology, PLA General Hospital, Beijing, People's Republic of China.
Dongyang
D
Kang
Department of Otolaryngology, PLA General Hospital, Beijing, People's Republic of China; Department of Otolaryngology, Hainan Branch of PLA General Hospital, Sanya, People's Republic of China.
Guojian
G
Wang
Department of Otolaryngology, PLA General Hospital, Beijing, People's Republic of China.
Dongyi
D
Han
Department of Otolaryngology, PLA General Hospital, Beijing, People's Republic of China; Department of Otolaryngology, Hainan Branch of PLA General Hospital, Sanya, People's Republic of China.
Pu
P
Dai
D016022:Case-Control Studies; D002681:China; D006319:Hearing Loss, Sensorineural / Q000235:genetics*; D006801:Humans; D026901:Membrane Transport Proteins / Q000235:genetics; D009154:Mutation; D020641:Polymorphism, Single Nucleotide; D024661:Potassium Channels, Inwardly Rectifying / Q000235:genetics*; D000076988:Sulfate Transporters; D014723:Vestibular Aqueduct / Q000002:abnormalities*; D000098854:Kcnj10 Channel
D000098854:Kcnj10 Channel; D026901:Membrane Transport Proteins; D024661:Potassium Channels, Inwardly Rectifying; C085609:SLC26A4 protein, human; D000076988:Sulfate Transporters