NKX6-1 and type 2 diabetes mellitus: Loss of β-cell identity in human T2D samples was shown by reduction of mRNA and protein levels of key β-cell identity markers: MAF BZIP Transcription Factor A (MafA) and NKX6 Homeobox 1 (Nkx6.1) and pancreatic and duodenal homeobox 1 (Pdx1) (27).