血瘦素遗传度的双生子分析

目的　观察遗传因素对血瘦素的影响。方法　 5 7对双生子 ,用微卫星 DNA基因扫描和分型技术 ,根据基因型的一致性来鉴别卵性。双生子间异同比较估计遗传和环境的相对效应 ,用放免法测定血清瘦素。结果　异卵双生子 (dizygotic,DZ)瘦素的对内方差大于同卵双生子 (monozygotic,MZ)的对内方差 (P<0 .0 5 ) ,前者为后者的 2倍多。但当校正体重指数 (body mass index,BMI)、性别和血尿酸 (uricacid,UA)后 ,MZ的对内方差接近于 DZ的对内方差。血瘦素的遗传度 8% ,校正 BMI、性别等的影响后血瘦素的遗传度为 0 .18%。血压与瘦素在简单相关分析时相关 (收缩压 r=0 .35 5 ,P<0 .0 0 1;舒张压 r=0 .339,P<0 .0 0 1) ,多元逐步回归分析时仅 BMI、性别和 UA入选方程 (R2 =0 .788,P<0 .0 0 1)。结论　遗传因素对血瘦素影响不大 ,血瘦素主要受环境因素影响。

Heritability of serum leptin levels:a twin study

Objective To study the contribution of genetic factors to the variance of serum leptin concentration in healthy, normotensive twins. Methods A total of 57 pairs of twins were investigated: 28 female and 19 male pairs of monozygotic(MZ) twins, and 6 female and 4 male pairs of dizygotic(DZ) twins. The zygosity of twins was determined by comparing the concordance of the genotype of nine fluorescence-labeled microsatellite markers. The genetic analysis was performed using the variance-based method. Serum leptin levels were determined in duplicate by a radioimmunoassay Kit (Linco Research, Inc., St. Charles, Missouri) as previously described. Results The test of genetic variance revealed a significantly larger within-pair variance of serum leptin in the DZ twins, in comparison with the MZ twins. The corresponding heritability for serum leptin was 8%. Adjusted for BMI, gender, and uric acid (UA), the heritability for serum leptin was 0.18%. Log leptin correlated significantly with blood pressure (SBp r = 0.355, P <0.001;DBp r =0.339, P <0.001). Stepwise multiple linear regression analysis revealed that only BMI, gender and UA were linked independently to serum leptin levels(R 2=0.788, P <0.001). Conclusion The above data indicate that environmental factors other than genetic factors are important determinants of leptinemia in normal subjects .