双生子瘦素的遗传度分析

Objectives: To study the contribution of genetic and environmental factors on the variation of leptin, and the effect of sex, age and body mass index (BMI). Methods: A total of 337 healthy same-sex twin pairs were studied, including 257 monozygotic (MZ) and 80 dizygotic (DZ) twin pairs aged 6~18(mean age, 12.3±3.5 years). Microsatellite polymorphism (STR) was used to diagnose zygosity of twins. Model-fitting method using Mx package was performed to analyze the genetic and environmental variance of leptin, before and after adjusting age and BMI. The effect of sex, age and BMI on the model was tested. Results: Leptin level was correlated with sex, age and BMI. Genetic analysis showed that the age variance contributed a lot in the total leptin variance among girls while the environmental variance contributed a lot among boys before the adjustment for age and BMI. After the adjustment the sex-specific additive genetic variance in male decreased and the best-fit model was ACE (scale) among both boys and girls. The heritability of leptin was 20%. Conclusions: Leptin level was associated with sex, age and BMI among child and adolescent. Gene and Environment influenced leptin together while environment seemed play a more important role relatively. The heritability of leptin was not affected by sex after the adjustment for age and BMI.