The IL18 rs1946518 and PTPN22 rs2476601 polymorphisms are not associated with adult- and childhood-onset type 1 diabetes mellitus
Type 1 diabetes mellitus (T1DM) is an autoimmune disease characterized by the destruction of pancreatic β-cells. Interleukins such as interleukin 18 (IL-18) and protein tyrosine phosphatase, nonreceptor type 22 (PTPN22) have been found to be associated with immune related diseases. We investigated a possible association of polymorphisms in IL-18 gene rs1946518 and PTPN22 rs2476601 with T1DM diagnosed in children (aged ≤14 years) and adults (aged ≥18 years) via a case-control study. In Euro-Brazilian children (n = 320) and adults (n = 291), patients with T1DM and healthy individuals (control) were genotyped for rs1946518 and rs2476601 using fluorescent probes (Taqman system). All groups were in the Hardy-Weinberg equilibrium. No significant differences were observed in the genotypes and allele frequencies for both polymorphisms. For the IL-18 rs1946518 A-allele, the minor allele frequencies for children, adults, healthy individuals, and T1DM were 49% (95% CI, 43.0–55.0), 47.5% (40–52), 47.9% (43–53), and 51% (45–57), respectively. For the PTPN22 rs2476601 T-allele in adults, controls and T1DM had frequencies of 7.3% (4–10) and 6.7% (4–10). In conclusion, these polymorphisms were not associated with T1DM onset in children or adults in this population.