C1QTNF9 and type 2 diabetes mellitus: The metabolites correlated with several DMRs in adolescents with T2D that were located near the transcriptional start sites (TSS) of several biologically relevant genes, including the free fatty acid receptor-1 (FFAR1), upstream transcription factor-2 (USF2), and the novel cytokine, tumor necrosis factor-related protein-9 (C1QTNF9).