双生子胰岛素敏感性的遗传度估计

目的：探索遗传和环境因素对胰岛素敏感性作用的大小。方法：采用稳态模型(homeostasis model assess—merit，HOMA)的对数来衡量249对双生子的胰岛素敏感性，其中同卵双生子169对，异卵双生子80对。将影响胰岛素敏感性的因素分成加性遗传方差(A)、显性遗传方差(D)、共同环境方差(C)和个体特殊环境方差(E)4个部分，用最大似然法拟合单变量遗传模型，同时考虑年龄和性别对胰岛素敏感性遗传度的影响。结果：年龄对胰岛素敏感性遗传度的影响没有显著性(x^2=1．851，P=0．604)，最适模型是AE模型，男性的遗传度为35％，女性的遗传度为46％。结论：本双生子人群遗传方差在胰岛素敏感性方差中所占的比重男性为35％，女性为46％。

Heritability of insulin sensitivity in twins

OBJECTIVE: To explore the contribution of genetic and environmental effects to insulin sensitivity. METHODS: The insulin sensitivity of 249 pairs of twins was estimated by use of logarithm transformed homeostasis model assessment (HOMA), of whom 169 pairs were monozygous and 80 pairs dizygous. To formulate a univariate genetic model for the variation of insulin sensitivity, the relative influences of gene and environment on the insulin sensitivity were divided into four contributing components as A (additive effects of alleles),D (dominance effects) C (common environmental effects) and E (specific environmental effects). Heritability of insulin sensitivity was estimated by maximum likelihood method, which included the influences of age and sex on model. RESULTS: The influence of age on insulin sensitivity was not significant chi(2)=1.851 P=0.604 . The AE-model fitted the data best. The heritability of insulin sensitivity was 0.35 in males and 0.46 in females, respectively. CONCLUSION: 35% of the variance in insulin sensitivity was due to additive effects in males and 46% due to additive effects in females in this twin study.