Genetic makeup affects 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."