Extrapituitary prolactin (PRL) production is regulated by the alternative promoter which contains functional single nucleotide polymorphism -1149 G/T. G allele of this SNP leads to higher mRNA PRL synthesis in lymphocytes.
Polymyositis (PM) and systemic sclerosis (SSc) have been associated with increased serum PRL levels, lymphocytes of patients with SSc produce more PRL mRNA. In our association study we tested 75 patients with SSc, 115 patients with polymyositis/dermatomyositis and 123 healthy individuals for -1149 G/T SNP of the extrapituitary PRL promoter.
The genotype and allele distribution did not show any differences in groups of PM, DM and SSc patients compared to healthy individuals. However, we found a significant inverse association between TT genotype in SSc patients with disease onset above 45 years compared to individuals with SSc and diseases onset prior 45 years and healthy subjects.