Distinct and novel SLC26A4/Pendrin mutations in Chinese and U.S. patients with nonsyndromic hearing loss.
Mutations of the human SLC26A4/PDS gene constitute the most common cause of syndromic and nonsyndromic hearing loss. Definition of the SLC26A4 mutation spectrum among different populations with sensorineural hearing loss is important for development of optimal genetic screening services for congenital hearing impairment. We screened for SLC26A4 mutations among Chinese and U.S. subjects with hearing loss, using denaturing HPLC (DHPLC) and direct DNA sequencing. Fifty-two of 55 Chinese subjects with deafness accompanied by enlargement of the vestibular aqueduct (EVA) exhibited at least one mutant SLC26A4 allele, whereas SLC26A4 mutations were found in only 2 of 116 deaf Chinese patients without EVA. The spectrum of SLC26A4 mutations differed among Chinese and U.S. subjects and included 10 previously unreported SLC26A4 variants: 4 in the Chinese population (p.E303Q, p.X329, p.X467, p.X573) and 6 in the U.S. population (p.V250A, p.D266N, p.F354S, p.D697A, p.K715N, p.E737D). Among the seven novel in-frame missense mutations, five encoded SLC26A4 proteins with substantially reduced Cl(-)/anion exchange activity as expressed and measured in Xenopus oocytes, but four of these were sufficiently active to allow study of anion selectivity. The only mutant polypeptide exhibiting complete loss of anion exchange function, p.E303Q, was expressed at or near the oocyte surface at near-wild-type levels. Two variants, p.F354S and p.E737D, displayed selective reduction in relative rate of Cl(-)/HCO(3)(-) exchange compared with similarly measured rates of Cl(-)/Cl(-) and Cl(-)/I(-) exchange. Our data show that mutation analysis of the SLC26A4 gene is of high diagnostic yield among subjects with deafness and bilateral EVA in both China and the U.S. However, the pathogenicity of monoallelic SLC26A4 gene variants in patients with hearing loss remains unclear in many instances.
Dai
Pu
P
Department of Otorhinolaryngology Head and Neck Surgery and Genetic Testing Center for Deafness, PLA General Hospital, Beijing, People's Republic of China.
Stewart
Andrew K
AK
Chebib
Fouad
F
Hsu
Ann
A
Rozenfeld
Julia
J
Huang
Deliang
D
Kang
Dongyang
D
Lip
Va
V
Fang
Hong
H
Shao
Hong
H
Liu
Xin
X
Yu
Fei
F
Yuan
Huijun
H
Kenna
Margaret
M
Miller
David T
DT
Shen
Yiping
Y
Yang
Weiyan
W
Zelikovic
Israel
I
Platt
Orah S
OS
Han
Dongyi
D
Alper
Seth L
SL
Wu
Bai-Lin
BL
D000483:Alleles; D000818:Animals; D044466:Asian People / Q000235:genetics*; D001483:Base Sequence; D002681:China; D002712:Chlorides / Q000378:metabolism; D002851:Chromatography, High Pressure Liquid / Q000379:methods; D004252:DNA Mutational Analysis; D005260:Female; D005787:Gene Frequency; D005838:Genotype; D034381:Hearing Loss / Q000208:ethnology / Q000235:genetics* / Q000473:pathology; D006801:Humans; D017136:Ion Transport; D026901:Membrane Transport Proteins / Q000235:genetics* / Q000502:physiology; D018613:Microscopy, Confocal; D009154:Mutation; D009865:Oocytes / Q000378:metabolism; D000076988:Sulfate Transporters; D014481:United States; D014723:Vestibular Aqueduct / Q000002:abnormalities / Q000378:metabolism; D044465:White People / Q000235:genetics*; D014982:Xenopus laevis
D002712:Chlorides; D026901:Membrane Transport Proteins; C085609:SLC26A4 protein, human; D000076988:Sulfate Transporters