IFITM5 and obesity due to melanocortin 4 receptor deficiency: There was no significant difference in proportion of overweight or obesity, and serum levels of FBG, FINS, HOMA-IR, HOMA-β, TG, TC, LDL-C, and HDL-C among COL1A1, COL1A2, IFITM5, and the autosomal recessive (AR) gene mutation group (Table 3).