Objective: To detect the mutations of gene connexin26 in the pedigrees of nonsyndromic hearing loss, and to make prenatal diagnosis and carry out early intervention to the pedigrees with mutations of gene con nexin26.
Method: The connexin26 gene of probands in 100 nonsyndromic hearing loss pedigrees was inspected by polymerase chain reaction, single strand conformational polymorphism and direct sequencing to detect the gene mutations. To the pregnant women in pedigrees with confirmed nosogenetic mutations of connexin26 gene, the prenatal diagnosis to the fetus by cordocentesis was made and the early intervention was carried out.
Result: The homozygous deletion C at position 233-235 of connexin26 cDNA was proved to be a nosogenetic mutation, and G79A, G109A, A341G, G442A, G506A and T608C were proved to be polymorphisms. In the prenatal diagnosis for the second pregnancy of a woman in a pedigree with the homozygous deletion C at position 233-235 of connexin26 cDNA, the same mutation in the fetus' connexin26 gene was found and she was advised to end the pregnancy.
Conclusion: The homozygous deletion C at position 233-235 of connexin26 cDNA will induce autosomal recessive nonsyndromic hereditary hearing loss and the heterogeneous mutation will not cause hearing loss. The prenatal diagnosis and early intervention can prevent the birth of deaf children. This is the first time in our country to make prenatal diagnosis and proceed early intervention to the fetus of hereditary hearing loss.