Aim: 

Aim of the study was to observe correlations between free saliva testosterone levels, polymorphisms of testosterone metabolism genes and cognitive abilities in different groups of individuals. Various groups of patients were used in this project: gifted children, elderly hypogonadic patients, patients with prostate cancer and individuals with autistic phenotype features.

Methods: 

Effects of testosterone could be influenced by several types of polymorphisms in genes, whose products participate on metabolism of steroid hormones, e.g.: androgen receptor gene (AR), aromatase gene (CYP19), 5a-reductase gene (SRD5A2), estrogen receptor gene (ESR1) and gene for sexual hormone binding protein. DNA samples were isolated from buccal cells in saliva and subsequently DNA was amplified by PCR. The CYP19 C¹⁵⁵⁸-T and SRD5A2 A49T polymorphisms were determined by RFLP analysis and the AR (CAG)_n polymorphism was determined by fragment analysis with fluorescently labeled primer. Salivary testosterone levels were measured with radioimmunoassay. Cognitive abilities were assessed via standard psychological tests – coefficient of mental rotation (CMR) and coefficient of spatial abilities (CSA).

Results: 

We found significant correlation between polymorphism A49T of SRD5A2 gene and CMR, as well as CSA in the group of gifted children. Polymorphisms of AR and CYP19 genes did not correlate with cognitive abilities. Gifted children of both sexes had lower levels of testosterone in comparison with their peers in common population.

Conclusions: 

Based on the hypothesis that intelligence and spatial abilities are influenced by genetic as well as epigenetic factors, it is not surprising that certain correlation between previously mentioned polymorphisms and cognitive abilities exist.