Relationship of type 1 diabetes to ancestral proportions and HLA DR/DQ alleles in a sample of the admixed Cuban population.
BACKGROUND
Incidence of type 1 diabetes varies widely around the world, probably due to ethnic differences across populations among other factors.


OBJECTIVE
To determine whether there is an association between disease and ancestry proportions; and to control disease-HLA associations for possible confounding by admixture or population stratification.


METHODS
100 cases and 129 controls participated in the study. Ancestry informative markers, which have considerable differences in frequency between European, West African and Native American populations were used. Type 1 diabetes associated HLA susceptibility/protection alleles were ascertained by PCR using specific primers. Statistical analyses were conducted using STRUCTURE 2.1, ADMIXMAP 3.7, SPSS 16.0 and STRAT 1.0 packages.


RESULTS
The results of logistic regression implemented in ADMIXMAP 3.7 indicated that European ancestry was associated with type 1 diabetes mellitus with an odds ratio of 5.7 corresponding to one unit change in European admixture proportion. Association was found between HLA alleles and disease, DQA1*0501, *0301 DQB1*0201 and DRB1*0301, *0401 being susceptibility alleles and DRB1*1501, DQA1*0102/3 and DQB1*0602 being protective alleles.


CONCLUSIONS
We found an association between European ancestry and type 1 diabetes in our sample, indicating the contribution of ethnicity to incidence differences. Previously reported associations of HLA DR/DQ alleles with disease are confirmed for the admixed Cuban population.
Diaz-Horta
Oscar
O
Departamento de Inmunologia y Genetica de la Diabetes, Instituto Nacional de Endocrinología, Zapata y D, Havana, Cuba. odiazor@infomed.sld.cu
Cintado
Alberto
A
Fernandez-De-Cossio
Maria Elena
ME
Nazabal
Marcelo
M
Ferrer
Annia
A
Roca
Juan
J
Camacho
Hamlet
H
Benítez
Jesus
J
Ale
Mayte
M
Villarreal
Adelaida
A
Molina
Gisela
G
Vera
Manuel
M
Cabrera-Rode
Eduardo
E
Novoa
Lidia
L
D000328:Adult; D000483:Alleles; D016022:Case-Control Studies; D003462:Cuba; D003922:Diabetes Mellitus, Type 1 / Q000453:epidemiology / Q000235:genetics* / Q000276:immunology*; D004198:Disease Susceptibility; D005260:Female; D005787:Gene Frequency; D005802:Genes, MHC Class II; D005819:Genetic Markers; D020022:Genetic Predisposition to Disease; D005838:Genotype; D006683:HLA-DQ Antigens / Q000235:genetics* / Q000276:immunology; D006684:HLA-DR Antigens / Q000235:genetics* / Q000276:immunology; D006239:Haplotypes; D006801:Humans; D008297:Male; D016133:Polymerase Chain Reaction; D020641:Polymorphism, Single Nucleotide; D018570:Risk Assessment
D005819:Genetic Markers; D006683:HLA-DQ Antigens; D006684:HLA-DR Antigens