DOI: 10.2337/db06-0856 © 2006 by the American Diabetes Association
Islet Autoimmunity in Children With Downs Syndrome
1 Diabetes and Metabolism Unit, Department of Clinical Science at North Bristol, University of Bristol, Bristol, U.K Address correspondence and reprint requests to Dr. K.M. Gillespie, Medical School Unit, Southmead Hospital, Bristol BS10 5NB, U.K. E-mail: k.m.gillespie{at}bristol.ac.uk
Abbreviations:
GADA, GAD antibody; IA-2A, IA-2 antibody; WHO, World Health Organization
There is an unexplained excess of type 1 diabetes and other organ-specific autoimmune diseases in children with Downs syndrome, but the immunogenetic characteristics of diabetes in Downs syndrome have not been investigated. We studied the frequency of islet autoantibodies in 106 children with Downs syndrome and no history of autoimmunity and analyzed HLA class II genotypes in 222 children with Downs syndrome, 40 children with Downs syndrome and type 1 diabetes, 120 age- and sex-matched children with type 1 diabetes, and 621 healthy control subjects. Co-occurrence of at least two islet autoantibody markers was observed in 6 of 106 nondiabetic children with Downs syndrome compared with 13 of 2,860 healthy age-matched children (P < 0.001). There was an excess of diabetes-associated HLA class II genotypes in children with Downs syndrome and type 1 diabetes compared with age- and sex-matched healthy control subjects (P < 0.001). Downs syndrome children with type 1 diabetes were, however, less likely to carry the highest risk genotype DR4-DQ8/DR3-DQ2 than children with type 1 diabetes from the general population (P = 0.01) but more likely to carry low-risk genotypes (P < 0.0001). The frequency of subclinical islet autoimmunity is increased in Downs syndrome, and susceptibility to type 1 diabetes in Downs syndrome is partially HLA mediated. Other factors, possibly including genes on chromosome 21, may increase the penetrance of type 1 diabetes in Downs syndrome.
|
|
|
|||||||||||||||||||||||||||