The IL12B 3′ untranslated region DNA polymorphism is not associated with early-onset type 1 diabetes

A recent study employing Australian and UK type 1 diabetes families has demonstrated significant transmission bias to affected offspring of a polymorphism (1188A allele; termed allele 1) in the 3' untranslated region (3'UTR) of the interleukin 12B (IL12B) gene which encodes the IL-12p40 subunit of the pro-inflammatory cytokine IL-12. However, results from replication studies in other populations have been controversial. We performed both case-control (n = 120 cases; n 330 controls) and family-based (n = 307 families) association studies, using the transmission disequilibrium test, to investigate if allele 1 is associated with early-onset type 1 diabetes in Northern Ireland. No association was observed between allele 1 and type 1 diabetes in either case-control (80.8% vs 80.8%; P = 0.98) or family-based (49.7% transmissions; P = 0.94) studies. Our results do not support earlier reports of an association between allele 1 in the 3'UTR of the IL12B gene and type 1 diabetes.