[Mutation analysis of Cx26 gene in Chinese hereditary nonsyndromic deafness sufferers].

OBJECTIVE

To analyze the mutations in the code region of Cx26 gene in Chinese hereditary nonsyndromic hearing impairment (NSHI) sufferers.

METHODS

Thirty-three cases (29 cases in the families of 8 students who were picked out from the Deafness and Muteness School of Tianjin, 2 cases as control and 2 normal cases of genetic counseling) were included in this study. The blood samples were obtained to distill the DNA templates. Using polymerase chain reaction (PCR), the code region of Cx26 gene was amplified. The mutations were screened by restriction endonucleases fingerprinting-single strand conformation polymorphism (REF-SSCP). Afterwards we inspected the polymorphous changes or mutations of these segments with DNA sequence.

RESULTS

There were 30 cases with the nucleotide changes in the Cx26 code region. The rate was 90.9% (30/33). Eight kinds of mutations were found, 79G-->A, 109G-->A, 161A-->T, 235delC, 240G-->A, 341A-->G, 571T-->C and 608T-->C. 161A-->T, 240G-->A and 571T-->C were detected primarily. There were 3 cases with 235delC in 22 deafness sufferers and the rate was 13.64% (3/22).

CONCLUSIONS

The 235delC of Cx26 gene is the main mutation in Chinese NSHI sufferers, and in NSHI cases many polymorphous changes exist.