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Conclusion: In the northwest of China, the prevalence of mutations of the three prominent deafness-related genes, GJB2, SLC26A4, and mitochondrial DNA (mtDNA) 12S rRNA, among Tibetan, Tu nationality, and Mongolian subjects is high, at 19%, 28.57%, and 21.05%, respectively. Molecular genetic screening for these mutations and genetic counseling are effective methods to prevent the occurrence of hereditary hearing loss. Objective: To analyze the prevalence of the three common deafness genes GJB2, mtDNA, and SLC26A4 gene mutations in Tibetan, Tu nationality, and Mongolian patients with nonsyndromic hearing impairment in the Northwest region of China. Methods: Genomic DNA was extracted from a total of 189 Tibetan, Tu nationality, and Mongolian probands from the northwest of China. PCR and direct sequencing were used to analyze the coding region of GJB2, mtDNA, and SLC26A4 genes. Results: The mutant allele rate of GJB2 gene was 6.2% in Tibetan and 11.22% in Tu nationality patients, c.235delC was the most prevalent mutation, accounting for 75% of the mutant GJB2 alleles. Mutant allele frequency of SLC26A4 in Tibetan, Tu nationality, and Mongolian subjects was 4.54%, 6.12%, and 15.79% respectively; p.IVS7-2A>G was the most common form. Mongolian cases were significantly higher than Tibetan cases (χ2 = 7.281, p = 0.007 and p < 0.05). mtDNA A1555G mutation was detected in six Tibetan, five Tu nationality, and one Mongolian subject; one Tibetan patient carried the C1494T mutation. [ABSTRACT FROM AUTHOR]

Aim: A cross-section study was conducted to explore the association between polymorphism of δ-aminolevulinic acid dehydratase (ALAD) and lead poisoning in Uygur and Han children in China. Methods: The ALAD genotyping was determined by PCR-RFLP in 443 Uygur and 469 Han children aged 6–10 years from Urumqi in Xinjiang province. Results: The blood lead levels of 912 environmentally exposed children ranged from 0.5 to 48.2 μg/dL, with a mean of 5.45 μg/dL and a standard deviation of 0.22 μg/dL, and 23. Thirty-one percent individuals were with blood lead level ≥10 μg/dL. The mean and standard deviation of blood lead levels were 5.57 ± 0.223 μg/dL and 5.30 ± 0.224 μg/dL in Uygur and Han children, respectively. The frequencies of the allele ALAD1 and ALAD2 in Uygur subjects were 90.52% and 9.48%, and in Han subjects were 95.73% and 4.27%, respectively (chi-square = 19.55, p < 0.05). No statistic correlation between the distribution of ALAD alleles and the blood lead level was found in both populations. Conclusion: A significant difference was seen in the frequency distribution of ALAD genotype between the different races. The genetic susceptibility of ALAD polymorphism to lead toxicity may exhibit in a lead dose-dependent manner. [ABSTRACT FROM AUTHOR]

Background. Cross-sectional studies investigated the impact of renin-angiotensin system (RAS) gene polymorphism on left ventricular mass index (LVMI) with conflicting results. We conducted a longitudinal study to investigate the influence of the angiotensin-converting enzyme (ACE) insertion/deletion (l/D) and angiotensinogen (AGT) M235T and angiotensin 11 type 1 receptor (ATI R) A1166C gene polymorphisms on the LVMI and geometry. Methods. Of 1500 people screened, 110 nondiabetic normotensive elderly Chinese persons were recruited and received echocardiography at baseline and at the 2nd and 4th year follow-up. No participants had a history of organic heart disease or chronic medication. The gene polymorphisms were analyzed by using polymerase chain reaction. Results. Participant age was 71.9 ± 3.9 years (range 60-81 years). The prevalence of concentric remodeling, eccentric hypertrophy, and concentric hypertrophy was significantly increased as well as LVMI after 4 years (all p < .05). These changes and the magnitude of LVMI increase were significantly higher in participants carrying the ACE D allele than non-D-allele carriers (all p < .05). This association was still significant in multivariate analyses (p < .02). A similar analysis showed a borderline significance in the ATI R but not in the AGT gene polymorphism. Conclusions. This longitudinal study showed that the aging process was associated with an increase of LVMI and changes of geometry. The RAS gene polymorphism, especially the ACE D allele, might modulale these changes in the Chinese population. This provides further knowledge that is essential in the assessment of cardiac disease and the determination of the left ventricular structure in older persons. [ABSTRACT FROM AUTHOR]