PRLR and obesity due to melanocortin 4 receptor deficiency: Moreover, genetic variants of the PRL locus (6p22.2 – p21.3) have been associated with alterations in body mass index in genome-wide association studies (18), and SNPs located near the PRLR gene correlate with an increased risk for gestational diabetes and obesity (19) strengthening the connection between prolactin and metabolic disorders.