Importantly, VFA (ρ = 0.513, p < 0.001) and HbA1c (ρ = 0.260, p = 0.001) were positively correlated with plasma XOR activity, which is consistent with previous reports including ours showing that obesity and glycemic control level are positively associated with plasma XOR activity20,21. The gene discussed is XDH; the disease is obesity due to melanocortin 4 receptor deficiency.