Secondly, because of the lack of gene expression data, this study may not provide direct evidence of the expression of HIF3A. Thirdly, the ideal tissues to identify epigenetic variations related to obesity or ALT should be adipose issues or hepatic issues, but we only investigated the methylation levels in peripheral blood because of difficulties in obtaining tissues from children. The gene discussed is HIF3A; the disease is obesity due to melanocortin 4 receptor deficiency.