Genetics play an important role in the variation in, and risk of, low testosterone concentrations in men. A study by the CHARGE Sex Hormone Consortium, published in the open-access journal PLoS Genetics on Thursday, 6th October, is the first genome-wide association study to examine the effects of common genetic variants on serum testosterone concentrations in men.
Testosterone is the principal male sex hormone and a potent anabolic steroid. It exerts a variety of important physiological effects on the human body. Low testosterone concentrations in men are associated with increased risk of cardiovascular morbidity, type 2 diabetes, atherosclerosis, osteoporosis, metabolic syndrome, and sarcopenia. Testosterone concentrations are known to decrease with age, but the observed inter-individual variability in testosterone concentrations in men is poorly understood.
By pooling the data of 14,429 Caucasian men, an international collaboration of 10 independent cohorts, co-led by the University of Gothenburg and the University of Greifswald, discovered genetic variants at the sex hormone-binding globulin (SHBG) gene and on the X chromosome associated with an increased risk of low testosterone.
Lead author Prof. Claes Ohlsson from the University of Gothenburg says: "This is the first large-scale study to identify specific genes for low serum testosterone concentrations. It is very interesting that the genetic contribution of the identified genetic variants to testosterone concentrations is substantial."
Co-senior author Dr. Robin Haring from the University of Greifswald concludes: "The reported associations may now be used in order to better understand the functional background of recently identified disease associations related to low testosterone concentrations in men."
Ohlsson C, Wallaschofski H, Lunetta KL, Stolk L, Perry JRB, et al. (2011) Genetic Determinants of Serum Testosterone Concentrations in Men. PLoS Genet 7(10): e1002313. doi:10.1371/journal.pgen.1002313