METTL3 and obesity due to melanocortin 4 receptor deficiency: Notably, altered levels of N6-methyladenosine (m6A) and its regulatory enzymes, including the eraser fat mass and obesity-associated protein (FTO) and the writer methyltransferase-like 3 (METTL3), have been detected in peripheral blood of T2DM patients, suggesting their potential as promising diagnostic markers.