ALDOB and obesity due to melanocortin 4 receptor deficiency: We also found that the previously identified markers of obesity fructose-biphosphate aldolase B (ALDOB), betaine-homocysteine methyltransferase (BHMT), and haptoglobin (Hp) were upregulated more than 4-fold in the HFD mice (74), and that several members of the complement system (Cfd, C8g, C8a, and C8b) were significantly depleted.