Serum levels of three selected miRNAs (miR‐15b, miR‐146b, and miR‐486), as well as of the betatrophin, were measured and compared between the groups of children with (>95th BMI percentile) or without (5th to 85th BMI percentile) obesity, and children suffering from diabetes (classification based on previous results of FPG, blood glucose, oral glucose tolerance test, or glycated haemoglobin [HbA1c]). The gene discussed is ANGPTL8; the disease is obesity due to melanocortin 4 receptor deficiency.