C1QTNF9 and obesity due to melanocortin 4 receptor deficiency: Furthermore, serum levels of CTRP9 protein are positively correlated with BMI, waist circumference, fasting insulin levels, decreased hemoglobin levels, and HOMA-IR, suggesting that the correlation between CTRP9 and non-alcoholic fatty liver is most likely due to the effect of CTRP9 on obesity (Zhang C. et al., 2018).