Thus, given the prominent role of genes MC4R and LPL in energy and metabolic homeostasis and since an adverse intrauterine environment (such as hyperglycemia and maternal obesity during pregnancy) can affect the DNA methylation pattern both in mothers and their offspring, the effects of DNA methylation in the promoters of these two candidate genes from some tissue, including placenta, maternal blood, and buccal swab samples collected in children born to women with and without obesity and GDM, were explored. The gene discussed is MC4R; the disease is obesity due to melanocortin 4 receptor deficiency.