[Programmed cell death 1 (PDCD1) gene polymorphisms and type 1 diabetes in Chilean children]

Abstract

Background: Programmed cell death 1 (PDCD-1) immune-receptor is a key element in the negative regulation of peripheral tolerance in T cells. Several polymorphisms of this gene have been described and it is linked with susceptibility to autoimmune diseases like Lupus and Multiple Sclerosis.

Aim: To analyze four gene polymorphisms of PDCD-1 gene and explore its possible contribution as a susceptibility gene for type 1 diabetes (T1D).

Patients and methods: We analyzed 160 cases with T1D of recent diagnosis aged 9.5 +/- 3.3 years and 160 control children aged 10.7 +/- 3.1 years. Four genetic variants of PDCD-1 gene were studied (PD1.2; PD1.5; PD1.6 and PD1.9) by polymerase chain reaction and restriction enzymes. Autoantibodies GAD65 and anti-IA-2 were also measured in all studied children. The comparison of allelic and genotypic frequency and consistency with respect to Hardy-Weinberg equilibrium test were analyzed using Chi-square and Fisher exact test.

Results: No differences between cases and controls were observed for PDCD1.2; PDCD1.5 and PDCD1.9 polymorphisms. PDCD1.6 polymorphism (carriers of allele A) had a higher frequency in the control group (0.794 versus 0.644, p < 0.017). There was no particular association of these polymorphisms with anti- GAD65 and anti-IA-2 antibodies among patients with T1D.

Conclusions: Only PDCD1.6 polymorphism showed differences between T1D cases and controls. Possibly, none of these genetic variants of PDCD1 has a relevant role as a marker for T1D in the Chilean population.