CTLA4 and type 2 diabetes mellitus: As far as we know, this is so far the most comprehensive meta-analysis about CTLA-4 gene polymorphisms and DM, and our pooled analyses revealed that rs231775 and rs5742909 polymorphisms may serve as genetic biomarkers of T1DM, and rs231775 polymorphism may also serve as a genetic biomarker of T2DM.