2000). The DCoH polypeptide has been identified as a dimerization cofactor of the HNF1A protein, which displays a restricted tissue distribution and does not bind to DNA, but selectively stabilizes HNF1A dimmers (Mendel et al. 1991; Rho et al. 2010). Also, it has been shown that the dimerization motif of the HNF1A protein forms an intermolecular 4‐helix bundle (Hua et al. 2000) which can be destabilized by a subset of MODY‐associated mutations. Thus, impaired dimerization of the beta‐cell transcription factor provides a molecular mechanism of metabolic deregulation in T2D (Hua et al. 2000). The gene discussed is HNF1A; the disease is type 2 diabetes mellitus.