The aim of our study was to identify possible HLA class I and MICA alleles and conserved extended haplotypes as risk factors for the development of CD in T1D.
The possibility that susceptibility to celiac disease (CD) might be influenced by the MHC class I chain-related gene family, MICA and MICB, has been previously reported.
No association was found for any of the MICA alleles independently of DQ genes, whereas TNF-alpha-308 A allele was slightly overrepresented on chromosomes carried by CD patients compared with control chromosomes, indicating that either TNF-alpha, or another gene in linkage disequilibrium with it, could confer increased susceptibility to CD.
In this study, we report a novel allele in the transmembrane region of the MICA gene consisting of seven GCT repeats found in a family based study of MICA polymorphism in celiac disease.
Our results indicate that although there is no primary association between MICA polymorphism and CD, there is, in addition to HLA-DQ, a second susceptibility locus on the 8.1 ancestral haplotype in strong linkage disequilibrium with MICA A5.1 allele.
In view of our results, both HLA-DRB1 and MICA are associated with CD, but stratification analysis did not show any independent contribution of the MICA polymorphisms analyzed to CD risk.