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Objective: To invesigate the molecular pathogenesis of deafness among the youth by means of genetic testing so as to provide pre-marriage genetic counseling and instruction for the deaf youth., Methods: 217 deaf young people, 126 males and 91 females, aged 18.9 (16 - 26), from Yunnan and Guizhou provinces, underwent history taking, auditory testing, and collection of peripheral blood samples. Genomic DNA and mitochondrial DNA were extracted to undergo sequence analysis of the entire gene GJB2, common point mutation of SLC26A4 gene, and mutation of mtDNA A1555G. Genetic prediction and marriage instruction were provided to each subject based on these results., Results: Twenty-three of the 117 persons (10.5%), 13 males and 10 females, were mtDNA A1555G mutation carriers and they were instructed that they, their maternal relatives, and the offspring of the female carriers, should they be born, should strictly avoid the administration of amino glycoside antibiotics. Twenty eight of the 115 persons (12.9%), were confirmed to carry homozygous or compound GJB2 mutations, 5 individuals (2.3%) carried heterozygous GJB2 mutation, 19 (8.8%) carried homozygous or compound SLC26A4 mutations, and one (0.5%) carried heterozygous SLC26A4 mutation. The suggestion for them was to avoid getting married with deaf partners caused by the same deaf gene or with individuals carrying mutations in the same deaf gene. Meanwhile, suggestions such as avoiding aggressive exercises and head injury were provided to the deaf young people with SLC26A4 mutations., Conclusion: Genetic testing can provide more accurate and useful genetic counseling and instruction to deaf young people for their partner selection and eugenics.

Objective: To investigate the prevalence of GJB2 mutations in Uigur and Han ethnic groups in Xinjiang Uigur Autonomous Region, China and to understand the mutation spectrum and frequency of the GJB2 gene in these 2 ethnic groups., Methods: Questionnaire survey was conducted among 61 Uigur deaf-mute students, 60 Han deaf-mute students, and 98 normal Uigurs and 301 normal Han people as controls. Peripheral blood samples were collected to undergo PCR and sequencing of GJB2 gene., Results: The GJB2 mutation rate of the Uigur deaf-mute students was 19.7%, not significantly different from that of the Han deaf-mute students (17.2%). GJB2 35delG was found only in the Uigur deaf-mutes with a carrier rate of 11.5%, whereas 235delC was identified in both Uigur and Han deaf-mutes. The allelic frequency of 35delG mutation in the Uigur and Han deaf-mutes and the Uigur controls were 7.4% (9/122), 0 (0/128), and 0 (0/196) respectively. The allelic frequencies of the GJB2 235delC mutations in the Uigur and Han deaf-mute students were 5.7% and 9.8%, and the allelic frequencies of 299 - 300delAT were 0.8% and 5.5%. V27I and E114G were the most frequent types of polymorphism., Conclusion: There is a rather high mutation rate of GJB2 gene in Xinjiang. The carrier frequency of 35delG of the Uigurs is significantly higher than that of the Han population. 235delC is common in both Uigur and Han people.