Immunogenetic, clinical, and demographic characterization of childhood type I diabetes in New Zealand.
OBJECTIVE
To examine the relationship between genetic susceptibility alleles and islet cell antibodies (ICAs) in type I diabetes.


METHODS
The human leukocyte antigen (HLA)-DQB1 alleles and ICA levels of all incident type I diabetic cases in patients < 20 years of age diagnosed in 1990 and 1991 in Canterbury, New Zealand, were determined.


RESULTS
The mean annual incidence rate for type I diabetes over the 24 months was 19.0/100,000 patient-years (95% confidence interval [CI] 13.5-26.0/100,000), which was considerably higher than rates observed between 1982 and 1989 (11.7/100,000; 95% CI 9.6-14.3/100,000). ICAs > or = 10 Juvenile Diabetes Foundation units (JDF U) were present in 84.6% of the subjects, but there was a higher prevalence of ICA-negative (ICA-) subjects among those diagnosed during the winter months. The frequencies of the susceptibility allele DQB1*0302 and susceptibility genotype 0302/0201 were 71.8% and 43.5%, respectively. Subjects with 0302 tended to be younger (mean age 8.3 +/- 5.1 years) than those with nonsusceptibility types (mean age 11.8 +/- 4.7 years, P = 0.056). The probability of being ICA positive (ICA+) was not significantly different between subjects with allele 0302 (85.7%) and those without it (81.8%). All seven patients negative for ICA were homozygous for DQB1 nonaspartate-57. There was no clustering of the immunogenetic markers with demographic and clinical characteristics apart from age at diagnosis.


CONCLUSIONS
No direct relationship was observed between DQB1-defined genetic susceptibility and ICA at diagnosis, suggesting that variations at the DQB1 locus are not linked to the expression of this autoimmune marker of beta-cell destruction.
Forbes
L V
LV
Lipid and Diabetes Research Group, Christchurch Hospital, New Zealand.
Scott
R S
RS
Brown
L J
LJ
Darlow
B A
BA
D000293:Adolescent; D000367:Age Factors; D000483:Alleles; D001323:Autoantibodies / Q000097:blood*; D002648:Child; D002675:Child, Preschool; D016001:Confidence Intervals; D004247:DNA / Q000097:blood / Q000302:isolation & purification; D003710:Demography; D003922:Diabetes Mellitus, Type 1 / Q000453:epidemiology* / Q000235:genetics / Q000276:immunology*; D004198:Disease Susceptibility; D005260:Female; D005787:Gene Frequency; D005838:Genotype; D006683:HLA-DQ Antigens / Q000097:blood / Q000235:genetics; D059866:HLA-DQ beta-Chains; D006650:Histocompatibility Testing; D006801:Humans; D015994:Incidence; D007223:Infant; D007515:Islets of Langerhans / Q000276:immunology; D008297:Male; D009520:New Zealand / Q000453:epidemiology; D016133:Polymerase Chain Reaction; D012150:Polymorphism, Restriction Fragment Length; D015995:Prevalence; D015183:Restriction Mapping; D012621:Seasons
D001323:Autoantibodies; D006683:HLA-DQ Antigens; D059866:HLA-DQ beta-Chains; C069051:HLA-DQB1 antigen; C024211:islet cell antibody; D004247:DNA