Referenced in: none

Automatically associated channels: Kir1.1 , Kir6.2

Title: HLA genotyping supports a nonautoimmune etiology in patients diagnosed with diabetes under the age of 6 months.

Authors: Emma L Edghill, Rachel J Dix, Sarah E Flanagan, Polly J Bingley, Andrew T Hattersley, Sian Ellard, Kathleen M Gillespie

Journal, date & volume: Diabetes, 2006 Jun , 55, 1895-8

PubMed link: http://www.ncbi.nlm.nih.gov/pubmed/16731860

Abstract
Children with permanent diabetes are usually assumed to have type 1 diabetes. It has recently been shown that there are genetic subgroups of diabetes that are often diagnosed during the neonatal period but may present later. A recent Italian study proposed that type 1 diabetes is rare before 6 months of age. We aimed to examine genetic susceptibility to type 1 diabetes in patients diagnosed with diabetes before the age of 2 years. We analyzed HLA class II genotypes, markers of autoimmune diabetes, in 187 children with permanent diabetes diagnosed at <2 years of age. Of the 79 subjects diagnosed at <6 months of age, 41% (95% CI 0.30-0.51) had type 1 diabetes-associated high-risk genotypes, a proportion similar to that in healthy population control subjects (44%, P=0.56). This group included 32 patients with mutations in the KCNJ11 gene, which encodes Kir6.2 (44% high-risk HLA class II genotypes), and 47 in whom the etiology of diabetes was unknown (38% high-risk HLA class II genotypes). Of 108 patients diagnosed between 6 and 24 months of age, 93% (0.86-0.99) had high-risk HLA class II genotypes compared with 44% of the population control subjects (P<0.0001). We conclude that infants diagnosed with diabetes before 6 months of age are unlikely to have autoimmune type 1 diabetes and are most likely to have a monogenic etiology.