TCF7L2 and type 2 diabetes mellitus: Even though some studies reported increased frequency of predisposing genotypes such as the T2D-associated variant in TCF7L2 transcription factor [5] or HLA T1D-susceptibility haplotypes [6, 7], major occurrence of less protective genotypes [8] and familial clustering linked to LADA pathogenesis [9], hereditary factors alone cannot explain progression towards β-cell failure in subjects at low genetic risk.