Mutations in the mitochondrial 12S rRNA gene in elderly Chinese people.
CONCLUSIONS
Our data indicate that the mitochondrial 12S rRNA gene, and particularly the A827G mutation, may be associated with susceptibility to age-related hearing loss.


OBJECTIVE
Hearing loss associated with aging is common among elderly persons. In all genetic backgrounds, mitochondrial DNA (mtDNA) mutations may be one of the most important factors contributing to aging and age-related hearing loss. The mitochondrial 12S rRNA is a hot spot for deafness-associated mutations in Chinese populations. The purpose of the present study was to elucidate the relationship of 12S rRNA gene polymorphisms and age-related hearing loss.


METHODS
The 12S rRNA gene polymorphisms were detected by direct sequencing. Statistical analyses were performed to assess the associations between age-related hearing loss and 12S rRNA gene variants.


RESULTS
We report here a systematic mutational screening of the mitochondrial 12S rRNA gene in 662 elderly subjects from the general population with various hearing threshold levels (211 controls and 451 age-related hearing loss subjects). Mutational screening of the mitochondrial 12S rRNA gene identified 55 nucleotide changes, including 4 mutations localized at highly conserved sites and 51 known variants. Of the known deafness-associated mutations in the mitochondrial 12S rRNA gene, the incidence of the A1555G mutation was 0.15%, A827G was 4.38%, T1095C was 0.45%, and T1005C was 3.78%. The incidence of the other known variants was 0.15-99.85%. We found statistically significant differences in the proportions of subjects with the A827G mutation among the various age-related hearing loss groups and normal controls.
Department of Otorhinolaryngology, Head and Neck Surgery, PLA General Hospital , Beijing , PR China.
Yuhua
Y
Zhu
Jiandong
J
Zhao
Bo
B
Feng
Yu
Y
Su
Dongyang
D
Kang
Huijun
H
Yuan
Suoqiang
S
Zhai
Pu
P
Dai
D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D044466:Asian People / Q000235:genetics*; D016022:Case-Control Studies; D002681:China; D005260:Female; D050259:Genes, Mitochondrial / Q000235:genetics*; D020022:Genetic Predisposition to Disease; D034381:Hearing Loss / Q000235:genetics*; D006801:Humans; D008297:Male; D008875:Middle Aged; D009154:Mutation / Q000235:genetics*; D011110:Polymorphism, Genetic / Q000235:genetics*; D012335:RNA, Ribosomal / Q000235:genetics*
D012335:RNA, Ribosomal; C075526:RNA, ribosomal, 12S
Hearing loss; age-related hearing loss; hereditary susceptibility; mitochondrial DNA; presbycusis