Although the mutations in MC4R gene became known as the most common genetic cause of human obesity, the effect of rs12970134 A/G near MC4R gene on insulin resistance has been described. The aim of this study was to determine the effect of rs12970134 on obesity, hormone levels, and glucose metabolism in a cohort of women varying in glucose tolerance: 850 normoglycemic women, 423 diagnosed with polycystic ovary syndrome ( PCOS), 402 gestational diabetics (GDM), and 250 type 2 diabetic (T2D) women.
We did not confirm the explicit effect of rs12970134 on obesity. However, the influence of the A-allele on body adiposity index was observed in a cohort of women diagnosed with PCOS.
In normoglycemic women, the A-allele carriership was associated with lower fasting levels of glucose, insulin, C-peptide, and index of insulin resistance. Furthermore, higher levels of growth hormone, leptin and SHBG, and lower levels of fT3, testosterone, and androstenedione were recorded in normoglycemic A-allele carriers.
In conclusion, the study presents the evidence of the impact of rs12970134 on complex hypothalamic regulations.