[Mitochondrial 12S rRNA gene A827G in two pedigrees with nonsyndromic deafness].
OBJECTIVE
To investigate the relationship of associating mitochondrial DNA 12S rRNA gene mutations with non-syndromic and aminoglycoside-induced hearing loss happening to Chinese families.


METHODS
The diagnosis was validated by hearing tests. Blood samples were collected from 20 family members (13 subjects from pedigree A and 7 from pedigree B) and 32 sporadic deafness cases. DNA was extracted from the leukocytes in blood samples. The gene fragments of mitochondrial DNA 12S rRNA, tRNA(Ser(UCN)) and GJB(2) were amplified by polymerase chain reaction (PCR). PCR products were analyzed by sequencing.


RESULTS
The target gene fragments of all individuals were successfully amplified by PCR. The mitochondrial DNA 12S rRNA 827 A to G transition was detected from all maternal members including 12 patients with hearing loss, which was the homoplasmic mutation. Non-maternal members in two pedigrees did not carry this mutation. However, the tRNA(Ser(UCN)) A7445G, 12SrRNA A1555G and GJB2 gene mutations were not found from both the family members of two pedigrees and sporadic patients. One sporadic individual (1/32) who was diagnosed as aminoglycoside-induced hearing impairment carried A827G mutation too.


CONCLUSIONS
It is confirmed that the mitochondrial DNA 12S rRNA gene is a hot spot for mutations associated with non-syndromic inherited hearing loss. The 12S rRNA nt827 A to G mutation may play a pivotal role in the pathogenesis of hearing impairment in two Chinese pedigrees.
Chen
Zhi-bin
ZB
Department of Otorhinolaryngology, the First Affiliated Hospital of Nanjing Medical University, Nanjing, Jiangsu 210029, P. R. China.
Cao
Xin
X
Xing
Guang-qian
GQ
Tian
Hui-qin
HQ
Zhou
Ai-dong
AD
Wei
Qinj-un
QU
Bu
Xing-kuan
XK
D000293:Adolescent; D001483:Base Sequence; D002648:Child; D002675:Child, Preschool; D000072259:Connexin 26; D017630:Connexins / Q000235:genetics; D004252:DNA Mutational Analysis; D004272:DNA, Mitochondrial / Q000737:chemistry / Q000235:genetics*; D003638:Deafness / Q000235:genetics*; D005260:Female; D020022:Genetic Predisposition to Disease / Q000235:genetics; D006801:Humans; D008297:Male; D010375:Pedigree; D017354:Point Mutation; D016133:Polymerase Chain Reaction; D012335:RNA, Ribosomal / Q000235:genetics*
D017630:Connexins; D004272:DNA, Mitochondrial; C000607042:GJB2 protein, human; D012335:RNA, Ribosomal; C075526:RNA, ribosomal, 12S; D000072259:Connexin 26