OGA and diabetes mellitus: Reportedly, the OGA gene MGEA5 is a DM-susceptibility locus in humans [11,12], and Goto-Kakizaki rats harboring an exon 8 deletion in Mgea5 spontaneously develop DM [13], suggesting that aberrant upregulation of O-GlcNAcylation is involved in the pathogenesis and/or complications of DM.