CTLA4 and type 1 diabetes mellitus: G alleles, A/G and G/G genotypes at the CTLA-4 locus (rs231775) were more frequent in T1D than in HT group (P = 0.009, OR = 1.63, 95%CI = 1.12–2.38, the power of the test 0.999, estimated effect size w equal to 0.246, with the total sample size n = 566, P = 0.003, OR = 2.42, 95%CI = 1.32–4.45 and P = 0.02, OR = 2.29, 95%CI = 1.12–4.81 the power of the test 0.999, estimated effect size w equal to 0.385, with the total sample size n = 283, respectively) (Figures 6, 7).