Association between the length of CAG repeats in exon 1 of the androgen receptor gene and metabolic syndrome in Chinese men / 西安交通大学学报(医学版)

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 mcn 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 dccreased 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.