TCF7L2 and diabetes mellitus: Gene variation in transcription factor 7 like 2 (TCF7L2) is a susceptible contributor to PDR (Table 1).217 The T allele of TCF7L2 rs7903146 is associated with fibrovascular membrane formation in type 2 diabetes mellitus-PDR patients.218 As part of the Wnt pathway, TCF7L2-regulated pathological neovascularization and VEGFA generation occur in diabetic models via ER stress-dependent pathways.218,219 The distribution of TCF7L2 is mainly in the cell nucleus of the RGCs layer and the inner nuclear layer.