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

Abstract
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.