C1QTNF1 and metabolic syndrome: Moreover, both CTRP1 and CTRP6 concentrations have already been measured in blood samples and serum levels were elevated in obese subjects [6,20,24,44] as well as in subjects suffering from associated diseases such as metabolic syndrome [45], type 2 diabetes mellitus [22,45,46,47,48,49,50,51], hypertension [52], and coronary artery disease [16,53,54].