Hyperprolactinemia (HPRL) is a classical side effect of anti-psychotic drugs. Extrapituitary prolactin (PRL) production is regulated by an alternative promoter, which contains the functional single nucleotide polymorphism – 1149 G/T (rs134,1239) in prolactin gene. We examined whether this polymorphism is associated with hyperprolactinemia in patients with schizophrenia. The experimental group comprised 443 patients with schizophrenia. The control group comprised 126 healthy persons. The PRL concentration was measured in serum using the AccuBind ELISA Microwells kit. The functional polymorphism – 1149 G/T (rs134,1239) of the PRL gene was genotyped using the The MassARRAY® system. Genotype and allele frequencies were compared using χ2 test. A total of 227 patients suffered from HPRL (98 males/129 females) according to the criteria of hyperprolactinemia. The frequency of genotypes and alleles in patients with schizophrenia did not differ from those in control subjects. A comparison between patients with schizophrenia with and without hyperprolactinemia revealed that the frequency of G allele in patients with hyperprolactinemia is significantly higher than in patients without hyperprolactinemia (χ2 = 7.25; P = 0.007; OR = 1.44 [1.10–1.89]). Accordingly, the genotype GG was found to be more often in patients with hyperprolactinemia than without it (χ2 = 9.49; P = 0.009). A significant association of the polymorphic variant rs134,1239 with the development of hyperprolactinemia in patients with schizophrenia treated with anti-psychotic drugs was revealed. Therefore, the serum concentration of prolactin in anti-psychotic treatment patients with schizophrenia may also give an indication of the activity of gene regulating extrapituitary prolactin expression.

The study was supported by the Russian Science Foundation, Grant 14-35-00023.