TCF7L2 and type 2 diabetes mellitus: The transcription factor 7-like 2 (TCF7L2) gene encodes a transcription factor involved in the WNT signaling pathway, and numerous studies show a correlation between TCF7L2 single nucleotide polymorphisms (SNPs) and dyslipidemia, metabolic syndrome and type 2 diabetes, [19, 41] which are known associated diseases of psoriasis [20].