Introduction: Sex hormone binding globulin (SHBG) levels have been associated with the development of the metabolic syndrome. In particular, low SHBG levels have been proposed as an indicator of increased risk for metabolic syndrome in men. The (TAAAA)n repeat polymorphism SHBG gene is believed to affect SHBG levels. In vitro experiments have shown that the allele with 6 TAAAA repeats is associated with decreased transcriptional activity of SHBG gene. The aim of this study was to examine the possible role of this polymorphism in the metabolic syndrome.
Subjects and methods: The study population consisted of 44 men with metabolic syndrome aged 51.6±9.9 years and 100 healthy men. The body mass index was recorded and blood samples were obtained after overnight fasting for biochemical and hormonal tests. The fasting glucose to insulin ratio was calculated as an indicator of insulin resistance. The SHBG (TAAAA)n polymorphism was genotyped in peripheral blood leucocytes.
Results: Genotype analysis for the (TAAAA)n polymorphism of the SHBG gene in the patients and controls revealed six alleles having 611 TAAAA repeats. The distribution of the alleles between patients and the control group did not show statistically significant differences. However, the 6/6 genotype was more frequent in patients with metabolic syndrome compared to healthy men (22.7% vs 11%, P=0.05). The small number of patients did not allow any association between polymorphism and biochemical parameters.
Conclusion: The (TAAAA)n polymorphism of SHBG gene appears to be associated with metabolic syndrome