C1QTNF12 and type 2 diabetes mellitus: Previous studies have reported irregularities in the serum levels of other CTRP family members, such as CTRP3 [27, 38], CTRP6 [28, 39] CTRP9 [1, 40], CTRP12, and CTRP13 [29, 41] in metabolic disorders including T2DM and PCOS.