In contrast, SHMT1 influences lipid metabolism through DNA methylation and adipocyte differentiation in metabolic diseases such as obesity and metabolic syndrome, whereas SHMT2 regulates mitochondrial function, glycine metabolism, and oxidative stress resistance (Table 1, Table 2, Table 3, Table 4). The gene discussed is SHMT1; the disease is obesity due to melanocortin 4 receptor deficiency.