The maternal high-fat exposure significantly increased mRNA N6-methyladenosine (m6A) levels in visceral fat at three weeks old, combined with downregulated Fat mass and obesity-associated gene (FTO) and upregulated Methyltransferase like 3 (METTL3) transcription, and these changes were reversed at eight weeks of age. The gene discussed is METTL3; the disease is obesity due to melanocortin 4 receptor deficiency.