The CTLA-4 49 A/G polymorphism was detected by the PCR-restriction fragment-length polymorphism (RFLP) method in 97 type 1 diabetic subjects and 20 patients with Graves' disease, a cohort which included 4 patients who also had type 1 diabetes.
Our data indicate that CTLA-4 exon 1 position 49 A/G dimorphism was significantly associated with predisposition to IDDM in our Central Poland population, particularly in patients lacking the strongly predisposing DRB1 alleles.