Most SNPs of the CTLA4 gene associated with autoimmune diseases are located within introns, with A+49G the only SNP found within an exon.[8] Overall, the data on the association of CTLA4 polymorphisms with T1D is convincing in some populations,[8–14] but not in others.[15–17] The identification of new SNPs for T1D is an important ongoing task. The gene discussed is CTLA4; the disease is type 1 diabetes mellitus.