Heterogeneity of vitamin D receptor gene association with celiac disease and type 1 diabetes mellitus.
OBJECTIVE
Vitamin D has been shown to exert multiple immunomodulatory effects and is known to suppress T-cell activation by binding to the vitamin D receptor (VDR). To determine whether VDR gene polymorphisms are related to the susceptibility to celiac disease, we investigated its implication as a candidate gene in the Basque population. Because celiac disease and type 1 diabetes share common susceptibility loci, we also analyzed families with type 1 diabetes mellitus.


METHODS
A total of 37 families with celiac disease and 64 type 1 diabetic families of Basque origin with at least one affected offspring were genotyped for four VDR restriction-site polymorphisms (Fok I, Bsm I, Apa I and Taq I). The AFBAC approach was used to test for association.


RESULTS
Comparison of VDR genotypes of the patients with those of 88 healthy individuals identified "ff" as a risk genotype for celiac disease [p = 0.01; OR = 3.45 (1.12-10.79)]. On the other hand, a significantly higher frequency of haplotype "fBAt" was observed in the type 1 diabetic group [p(c) = 0.02; OR = 4.4 (1.5-15.3)].


CONCLUSIONS
Our findings suggest that polymorphisms within the vitamin D receptor gene are markers of susceptibility to or protection from autoimmune diseases, although, at least in the Basque population, association of VDR variants with celiac disease and type 1 diabetes seems to be heterogeneous.
San-Pedro
J I
JI
Research Unit, Hospital de Cruces, Barakaldo, Basque Country, Spain.
Bilbao
J R
JR
Perez de Nanclares
G
G
Vitoria
J C
JC
Martul
P
P
Castaño
L
L
D002446:Celiac Disease / Q000235:genetics* / Q000378:metabolism*; D002675:Child, Preschool; D003922:Diabetes Mellitus, Type 1 / Q000235:genetics* / Q000378:metabolism*; D018740:Genetic Heterogeneity; D005819:Genetic Markers; D020022:Genetic Predisposition to Disease; D014644:Genetic Variation; D006801:Humans; D012150:Polymorphism, Restriction Fragment Length / Q000235:genetics; D018167:Receptors, Calcitriol / Q000235:genetics*
D005819:Genetic Markers; D018167:Receptors, Calcitriol