Heritability Of Serum Uric Acid And BMI Phenotype Of Twins

Objective:To discuss the effect of hereditary and environment on serum uric acid and BMI penotypes; To verify whether uric acid and BMI phenotype are effected by genetic and/or common environmental factors.Methods:The study participants were recruited from the Qingdao Twin Registry. Serum Uric Acid, height, weight were measured, and BMI was caculated. Zygosity in all same-sex twin pairs was confirmed determined by genotyping with 16 polymorphic markers. SPSS and Mx software package were used as the statistical methods to build structural equation models. At first, heritability was assessed by structural variance component genetic modeling equation models. With age and sex were used for adjusting Uric Acid and BMI included as covariate, then computed twin correlations and cross-trait cross-twin correlations between serum uric acid and BMI phenotypes for monozygotic (MZ) and dizygotic (DZ) twins and carried out modcl-fitting analyses using a Birivariate Cholesky model with age and sex included as covariate.Results:In total,679 twin pairs aged 24 and above years were available for data analyses, including 413 pairs of monozygotic twins and 266 pairs of dizygotic twins. Original serum uric acid was 271.6±69.5 u mol/L, BMI phenotye was 24.19±3.25Kg/m2. After transformation, age and sex adjustment, we built the structural equation models, a AE model combining additive genetic and unique environmental factors produced the best fit for the data of serum uric acid and BMI. Heritability estimates for serum uric acid were 71.2% (95% confidence interval [CI]:73.8%-81.7%). Heritability estimates for BMI were 76.6% (95% confidence interval [CI]:89.0%-92.5%).The phenotypic correlation between serum uric acid and BMI was 0.302. When the data was adjusted for age and sex, the correlation was changed to 0.276. Bivariate Cholesky decomposition ananlysis indicated, the best model for them was model (drop shares environmental Var-co variances among serum uric acid and BMI). The genetic correlation between serum uric acid and BMI phenotypes was 0.26 (95% confidence interval [CI]:0.17-0.36), suggesting that a set of common genes affect both phenotypes (pleiotropy). From this we calculated that the proportion of the correlation between serum uric acid and BMI phenotypes by common genetic factors was 69.6%. Of heritability for serum uric acid, only 5% were shared with the BMI phenotype.Conclusion:serum uric acid and BMI phenotypes are influenced mostly by inheritance. There are genetically correlations between serum uric acid and BMI phenotype of twins, Some genes effect the level of serum uric acid and BMI, but epigenetic effects are mainly from their own specific genetic effect.