Candidate Gene Region 15q26 and Genetic Susceptibility to Coeliac Disease in Finnish Families

Abstract

BACKGROUND: Studies in the Irish and British populations have indicated that chromosome region 15q26 could include a novel non-HLA-linked locus conferring genetic susceptibility to coeliac disease. The locus is of particular interest, since a type I diabetes risk locus, IDDM3, maps to the same position. It was tested whether this locus shows evidence for genetic linkage to coeliac disease in Finland. METHODS: Ninety-nine Finnish families with at least one affected sibpair were studied. Five microsatellite markers mapped within approximately 20 cM region on chromosome 15q26 were typed. Non-parametric linkage (NPL) scores and allelic transmission (TDT) were studied. RESULTS: No evidence for genetic linkage could be obtained by the NPL scores calculated by the Genehunter program. However, transmission/disequilibrium analysis (TDT) revealed that haplotype D15S107*1-D15S120*6 was statistically significantly more frequently transmitted to affected than expected by chance (TDT chi2 9.0; P = 0.003). The subgroup of families having this haplotype, however, did not differ from the others, regarding to disease manifestation, HLA status, or geographical origin. CONCLUSION: The 15q26 region appears not to be a major non-HLA susceptibility locus for gluten sensitivity in Finland, but a particular haplotype which may harbour a susceptibility gene was identified.