A number of CD-susceptibility loci have previously been defined, and all of these generate strong signals in our data (Table 2). In 2001, positional cloning identified CARD15 (caspase recruitment domain family, member 15; NOD2) as the first confirmed CD-susceptibility gene60,61. In the present study, this locus is represented by rs17221417 (P=9.4×10-12). A second association, on chromosome 5q31 (ref. 62) has been widely replicated, although the identity of the causative gene is disputed owing to extensive regional linkage disequilibrium63. Here, the previously described risk haplotype is tagged by rs6596075 (P=5.4×10-7).
