CTLA4 and type 1 diabetes mellitus: In this study, we found that children carrying the G allele in CTLA4 +49A/G had a 1.33-fold increased risk of developing T1D in comparison to children carrying the A allele; children who had a GG or GA genotype had a 1.75- or 1.26-fold higher risk, respectively, of developing T1D than children who had the AA genotype.