RESUMEN
Background: The programmed cell death 1 (PDCD-1) immune-receptor is a key element in the negative regulation of peripheral tolerance in T cells. The gene has several polymorphisms and can be associated with susceptibility to autoimmune diseases. Aim: To analyze the frequency and distribution of PD-1.3 polymorphism of PDCD-1 gene and explore its possible contribution as a susceptibility gene for type 1 diabetes (T1D). Patients and Methods: We analyzed 248 cases with T1D with recent diagnosis and 160 control children under 15 years of Santiago. Genetic polymorphism in PD-1 gene variant for PD-1.3 (rs 11568821) was analyzed by polymerase chain reaction and restriction fragment length polymorphism. Comparison of genotype, allele frequency and consistency with respect to Hardy-Weinberg were analyzed using X2 tests and Fisher exact test. Results: There was a very low frequency of the genotype A/A, both in T1D patients and in controls (< 2 percent). The A/G genotype was more common in diabetic patients than in controls (41.6 and 18.8 percent respectively, p < 0.04). G/G genotype was more common in controls than in patients (79.4 and 56.8 percent respectively, p < 0.02). T1D patients carrying genotype G/G had a higher frequency of anti-GAD65 and anti-A-2 antibodies (81 and 67 percent respectively). Conclusions: The distribution of PD-1.3 genotype frequencies are similar to that reported elsewhere. Possibly, this genetic variant (rs 11568821) does not have an important marker role in Chilean T1D patients.