Overall, in humans, the BMP-9 concentration in serum decreases with pathologic conditions like obesity, hypertension, insulin resistance, fatty liver disease, type II diabetes as well as coronary heart disease, venous malformations, COVID-19 infection, and sepsis [11,15,17 20,23,25,26]. The gene discussed is GDF2; the disease is obesity due to melanocortin 4 receptor deficiency.