This is, to our knowledge, the first GWAS reported for CD. To obtain these findings, we made use of our own SSADDA-assessed GWAS sample, an additional SSADDA-assessed replication sample, and publicly available data from the SAGE project. Our strongest finding statistically, and the only one that meets genomewide significance in the entire sample (i.e., p<5×10−8), is at FAM53B (Figure 2, Table 2). Although both the AA and EA parts of the sample contributed to this association signal, it was stronger in AAs, where the MAF was 0.07, vs. 0.25 in the EAs. FAM53B falls within the 1-lod support interval of the most significant genome-wide linkage peak for CD (lod score 2.7) that we identified previously.5 As in the present association result, both the EA and AA parts of the sample contributed to the linkage finding. It is relatively uncommon for association and linkage findings to coincide in this way. The previous positional information from linkage increases the probability that the association finding is valid.
