The Relationship Between TNF, PDE8B, TSHR Gene Polymorphism And Endemic Goiter Of 8-10 Year-old Children

Objective: Goiter refers to the thyroid,which increases in size and shape. At present, environmental factors which lead to goiter, had been studied for a long time. However, as for the genetic factors, there are only a few studies. TNF, PDE8B, TSHR gene polymorphism and thyroid function and iodine metabolism are closely related, which may be related to environmental factors, leading to the occurrence of goiter.Children aged 8 to 10 received the investigation and medical examination. The purpose is to understand the prevalence of goiter. They are come from five townships of Wuqiao county. Blood specimens was collected for laboratory study, which was used to examine the relationship between TNF, PDE8B, TSHR gene polymorphism and endemic goiter of 8-10 year-old children. Reveal the genetic susceptibility of goiter of 8-10 year-old children.Methods: Township (town) was randomly selected from five different directions (east, west, south, north, middle) of Wuqiao County. Five villages were randomly selected from five different directions (east, west, south, north, middle) of each township (town), 25 villages was got into an investigation. subjects of survey were school children of 8-10 years, and the total number is 1209. According to WS276-2007 (endemic goiter the diagnosis and sub-degree standard) diagnostic criteria, two experienced professional doctors use thyroid palpation to Check thyroid size. The survey found a total of 74 cases of goiter children, goiter rate was 6.1%. At the same time 146 cases of randomly selected healthy children, as a normal control group. Venous blood of 5ml were collected, guanidine hydrochloric acid extraction of whole blood genomic DNA. First, fragment was amplified by polymerase chain reaction, and fragments were sequenced to determine the specimen TNF308 (rs1800629) A / G, PDE8B (rs4704397) A / G, and TSHR (rs2268458) C / T genotype, and then use high-resolution melting curve analysis to determine each sample TNF308 (rs1800629) A / G, PDE8B (rs4704397) A / G, and TSHR (rs2268458) C / T genotype, the final analysis, the relationship between gene polymorphism and goiter. Simultaneous Detection of thyroid function parameters, including the major serum, such as Free Triiodothyronine (FT3), serum free thyroxine (FT4) and thyroid stimulating hormone (TSH) of three biochemical indicators. For all measurement data was tested for Normality, gene frequency of each group was tested for Hardy-Weinberg equilibrium method. mean±standard deviation (—x±s) was used to stand for Normal distribution of the information; the median (min, max) was used to stand for non-normality of the distribution of information. Measurement data of the groups were compared with t or t' test; count data between the two groups using x2 test; goiter risk factors by Logistic regression analysis. All data information was used to establish a database through Excel2003, which was processed by SPSS13.0 statistical analysis software package.Results: (1) The survey of 1209 children in school, found a total of 74 cases of goiter children, goiter rate was 6.1%. average age and gender of the child with goiter, comparied with the normal control group, no significant difference between the two groups (p> 0.05); FT3, FT4, TSH three indicators in the control group and goiter group, no significant difference between the two groups (p> 0.05). (2) TNF genotypes and two alleles in the two groups in the distribution: A, G allele, and two kinds of GA, GG genotypes are exist in goiter group and the normal control group, The actual observed value substituted into the Hardy-Weinberg equilibrium equation, first calculate the theoretical value of all genotypes, genotypes were detected using X2 test the theoretical expected value and the actual measured values of the degree of fit between the validation. The test results showed: X2 values of each group were less than 3.84 (X20.05 = 3.84, df = 1), that is, p values are greater than 0.05, indicating the actual gene frequencies and expected differences in gene frequency was not statistically significant, the distribution of consistent with Hardy-Weinberg equilibrium, it can representative population. The normal control group and group of goiter GG genotype frequencies were 90.41% and 91.89%, no statistical significance; the normal control group and the goiter group G genotype frequencies were 95.21% and 95.95%, no statistical significance. The use of GA and GG genotype distribution in the two groups, calculated OR = 0.83, 95% CI of 0.30-2.29, indicating a different genetic Type in no difference in the prevalence of endemic goiter. The use of A and G genotype distribution in the two groups, calculated OR = 1.19, 95% CI of 0.44-3.18, indicating different alleles in the endemic goiter prevalence rate there was no difference (3) PDE8B genotypes and two alleles in the two groups in the distribution: A, G allele, and two kinds of AA, AG genotypes are exist in goiter group and the normal control group, The actual observed value substituted into the Hardy-Weinberg equilibrium equation, first calculate the theoretical value of all genotypes, genotypes were detected using X2 test the theoretical expected value and the actual measured values of the degree of fit between the validation. The test results showed: X2 values of each group were less than 3.84 (X20.05 = 3.84, df = 1), that is , the p values are greater than 0.05, indicating the actual gene frequencies and expected differences in gene frequency was not statistically significant, the distribution of consistent with Hardy-Weinberg equilibrium, it can representative population. The normal control group and goiter group AG genotype frequencies were 20.55% and 33.78%, statistically significant, thyroid enlarged Group AG genotype frequency was significantly higher than the normal control group; the normal control group and goiter group G genotype frequencies were 10.27% and 16.89%, statistically significant, goiter group G allele frequencies were significantly higher than the normal control group. The use of AA and AG genotype distribution in the two groups, calculated OR = 1.97, 95% CI of 1.06-3.66, indicating the risk of AG genotype suffered from endemic goiter was 1.97 times the risk of AA genotype. The use of A and G genotype distribution in the two groups, calculated OR = 1.76, 95% CI of 1.01-3.08, indicating the risk of G allele carriers suffered from endemic goiter was 1.76 times the risk of the A allele carriers. (4) TSHR genotypes and two alleles in the two groups in the distribution: C, T allele, and two kinds of CC, CT, TT three kinds of genotypes are exist in goiter group and the normal control group, the actual observed value substituted into the Hardy-Weinberg equilibrium equation, first calculate the theoretical value of all genotypes, genotypes were detected using X2 test the theoretical expected value and the actual measured values of the degree of fit between the validation. The test results showed: X2 values of each group were less than 3.84 (X20.05 = 3.84, df = 1), that is, p values are greater than 0.05, indicating the actual gene frequencies and expected differences in gene frequency was not statistically significant, the distribution of consistent with Hardy-Weinberg equilibrium, it can representative population.The normal control group and goiter group TT genotype frequencies were 15.75% and 13.51%, no statistical significance; normal the control group and the goiter group T genotype frequencies were 32.53% and 31.08%, no statistical significance. The use of CC, CT, TT genotype in the two groups of three kinds of distribution, calculated OR = 1.20, 95% CI of 0.53-2.73 to illustrate different genotypes in no difference in the prevalence of endemic goiter. The use of C and T genotype distribution in the two group, calculated OR = 1.07, 95% CI of 0.70-1.63, indicating different alleles in no difference in the prevalence of endemic goiter. (5) risk factors of endemic goiter analysis: whether the endemic goiter (EG) as the dependent variable, TNF genotype, PDE8B genotype, TSHR genotype, FT3, FT4, TSH for independent variables, using multi-factor non-conditional Logistic regression analysis of multiple factors on the incidence of the impact of EG showed that only PDE8B gene polymorphism (OR = 2.03,95% CI of 1.06-3.88) and TSH (OR = 2.23,95% CI = 1.14-4.37) are risk factors of endemic goiter, and another one FT4 (OR = 0.42,95% CI of 0.21-0.84) is a protective factor in endemic goiter.Conclusion: (1) PDE8B (rs4704397) A / G polymorphism and endemic goiter are related with each other, G allele may be the susceptibility gene of endemic goiter. (2) There is no relationship between TNF308 (rs1800629) A / G polymorphism and endemic goiter. (3) There is no relationship between TSHR (rs2268458) C / T gene polymorphism and endemic goiter.