FTO and obesity due to melanocortin 4 receptor deficiency: The aims of our study were therefore (1) to investigate the genotype frequency of FTO gene rs9939609 in Polish PSO group, inhabitants of Lower Silesia; (2) to assess the relationship between the presence of risk allele and severity of PSO; (3) to examine the association of risk allele and obesity, hypertension, and some carbohydrate disturbances.