CARD15 mutations in patients with Crohn's disease in a homogeneous Spanish population.

OBJECTIVES

Three mutations in CARD15 have been repeatedly shown to be involved in Crohn's disease susceptibility, mainly in Caucasian individuals. However, those findings were not replicated in all populations studied so far. In this work, we studied the role of CARD15 mutations in a relatively homogeneous population from the Northwest of Spain, Galicia.

METHODS

One hundred and sixty-five patients with Crohn's disease and a similar number of healthy controls were recruited from a single center in Galicia. All individuals were genotyped for the three main Crohn's disease associated CARD15 variants (R702W, G908R, and 1007fs). Association analyses were performed to study the influence of those mutations on Crohn's disease overall and on clinical subphenotypes.

RESULTS

The allele frequencies of CARD15 variants were lower in this population than in most of the European populations studied so far. G908R and 1007fs were significantly associated with overall susceptibility to Crohn's disease. However, these associations were lost after stratification to clinical subgroups, probably due to the small number of cases in these subgroups. Significant associations were found between G908R and 1007fs and the behavior of Crohn's disease, but they were due to the influence of years of disease on the behavior of the disease rather than being the result of a direct effect of these mutations on disease behavior.

CONCLUSIONS

The CARD15 variants G908R and 1007fs, but not R702W, are associated with susceptibility to Crohn's disease in Galicia. Interestingly, the frequency of these mutations appears to be lower than in other Caucasian populations studied so far.