雄激素受体基因外显子一CAG重复序列长度多态性与男性代谢综合征的相关性
Association between the length of CAG repeats in exon 1 of the androgen receptor gene and metabolic syndrome in Chinese men

摘要：目的 研究雄激素受体(AR)基因第一外显子内CAG重复序列长度多态性与男性代谢综合征(MS)及其组成成分的相关性。方法 采用整群抽样法，选择宁夏吴忠市和银川市中老年男性910例。测量其身高、体质量、血压，检测睾酮(TT)、血脂、空腹血糖(FBG)、空腹胰岛素(FINS)水平，计算体质量指数(BMI)和游离睾酮(FT)，使用聚合酶链反应(PCR)和直接测序法测定外周血AR基因CAG重复序列长度。根据是否患有MS分为MS组(共304例)和正常对照组(共606例)。结果 正常对照组与MS组的AR基因CAG重复序列长度多态性的频率分布无明显差异。CAG重复序列数<22组的收缩压显著高于CAG重复序列数≥22组，而高密度脂蛋白(HDL-C)浓度显著低于CAG重复序列数≥22组。但两组间的舒张压、其他血脂水平、FBG、FINS、BMI、TT、FT指标均没有统计学差异。CAG重复序列数<22组较CAG重复序列数≥22组有更高的高血压患病率，但是两组之间的MS及其他组成成分疾病的患病率并无统计学差异。结论 AR基因CAG重复序列长度多态性与高血压病和HDL-C水平降低的发生有关，但是与MS的患病率无关。AR基因外显子一CAG重复序列数目<22可能是患高血压病和HDL-C水平降低的遗传因素。
ABSTRACT: Objective To study the association of the CAG repeat length polymorphism in exon 1 of the androgen receptor (AR) gene with metabolic syndrome (MS) and its components in men. Methods We used cluster sampling method to select 910 middle- and old-aged male subjects from the communities in Yinchuan and Wuzhong cities, Ningxia. Their body height, weight and blood pressure were measured; their testosterone (TT), serum lipids, fasting glucose (FBG) and fasting insulin (FINS) were assayed; and their body mass index (BMI) and free testosterone (FT) were calculated. Length of CAG repeats in exon 1 of the AR gene was determined by polymerase chain reaction (PCR) and direct sequencing method. The subjects were divided into MS group (n=304) and normal control group (n=606) according to the diagnosis standards of MS. Results No obvious difference in the frequency distribution of CAG repeats in the AR gene was found between MS group and normal control group. The systolic blood pressure in the men with CAG repeat number of less than 22 was significantly higher than that in those with CAG repeat number of 22 or more, but HDL-C was significantly lower than men with CAG repeat number of 22 or more. However, the two groups did not significantly differ in diastolic blood pressure, other blood lipids level, FBG, FINS, BMI, TT or FT. The men with CAG repeat number of less than 22 had a higher prevalence of hypertension than those with CAG repeat number of 22 or more, but the prevalence of MS and other components of MS in the two groups had no significant difference. Conclusion The length of CAG repeats in exon 1 of the AR gene is related to the occurrence of hypertension and the decreased level of HDL-C, but not to the incidence of MS. The number (less than 22) of CAG repeats of the AR gene may be a genetic factor of the occurrence of hypertension and reduced level of HDL-C