性别因素对原发性高血压候选基因研究的影响作用

目的探讨研究样本中的性别因素对原发性高血压（EH）候选基因研究结果的影响。方法应用聚合酶链反应这一分子生物学研究方法,分析EH组患者及正常血压对照组（两组中男性女性人数相等）人群血管紧张素转换酶（ACE）基因插入／缺失（I／D）多态性,进而探讨性别比例对该类研究结论的可能影响。结果男性EH组DD基因型频率显著高于男性对照组（x^2=6．98,P=0．004）,D等位基因频率在男性EH组亦较男性对照组显著增高（x^2=6．87,P=0．009）,而ID和II基因型频率在男性EH组和男性对照组间差异无统计学意义（P〉0．05）。女性EH组与女性对照组比较,各基因型和等位基因频率分布差异均无统计学意义（P〉0．05）;男性EH组中的DD基因型分布比例与女性EH组中的DD基因型分布比例相比有显著统计学意义（x^2=4．06,P=0．044）。此外,EH组中男性DD型者的收缩压及脉压水平均显著高于ID型和II型者（P均〈0．05）,但舒张压在3种基因型间差异无统计学意义（P〉0．05）。同时,EH组II、ID基因型的男性的收缩压、舒张压、脉压差异均无统计学意义（P〉0．05）。女性患者中,各基因型间收缩压、舒张压及脉压的水平差异均无统计学意义（P〉0．05）。结论男性中的DD基因型成员与EH（尤其在收缩压、脉压）的关联可能比男性中的II、ID基因型以及所有的女性更为密切。性别可能作为一个混杂因素,对包括ACE基因I／D多态性在内的诸多EH候选基因与EH的相关性研究的结论产生影响。

The impact of gender factor on the candidate gene study of essential hypertension

OBJECTIVE: To study the impact of gender factor on the candidate gene study of essential hypertension (EH). METHODS: The polymerase chain reaction (PCR) was performed to analyze the ACE gene I/D polymorphism of hypertensive patients (50 men and 50 women) and normal controls (50 men and 50 women). The investigation was further focused on possible influence of sex proportion on the conclusion of this kind of research. RESULTS: The frequency of DD genotype in male hypertensive patients is significantly higher than that in male normal controls (chi(2) = 6.98, P = 0.004). The frequency of D allele in male EH group is significantly higher than that of male normal controls (chi(2) = 6.87, P = 0.009), while no significant difference was observed for II and ID genotype between male EH group and control group (P > 0.05). For female EH group and normal controls, there were no significant differences in frequency of genotype and allele (P > 0.05), the distribution ratio of DD genotype in male EH group is significantly different from that of female EH group (chi(2) = 4.06, P = 0.044). Furthermore, males with DD genotype in EH group had higher SBP and PP than that of males with II and ID genotype (P < 0.05). However, there was no significant difference in DBP in all three genotypes (P > 0.05). At the same time, there was no difference in SBP, DBP and PP (P > 0.05) between II and ID genotype in male EH group. In female hypertensive patients, there was no significant difference in SBP, DBP and PP between all three genotypes (P > 0.05). CONCLUSIONS: The relationship between DD genotype in male and EH (especially SBP and PP) is closer than any other genotype-EH relationships in both male and female. The gender factor, as a probable confounding factor, can affect many candidate gene studies of essential hypertension including ACE gene I/D polymorphism, and thus biases the conclusion.