Figure 4. Visual display of results found in 21 positive studies of the top-ranked gene in Crohn's disease, CYLD.

As a illustrative example for all P/PI genes, the CYLD (cylindromatosis/turban tumor syndrome, chr16q12.1, 49.33–49.39 Mb) gene is shown. CYLD was mapped onto the critical regions shaded in grey. The critical regions of later studies, including genome-wide association scans and replications of genome-wide association scans and some candidate region studies, were more narrow compared with critical regions of earlier studies because of the improved resolution of more recent genotyping platforms.