Inflammatory bowel disease (IBD) is a group of conditions having an unknown cause, but with a genetic component clearly demonstrated by epidemiological and linkage studies. A link with chromosome 3 is suggested by observations of a gene, or perhaps multiple genes, involved in regulating immune function and inflammatory response that reside in this region of the genome.
In the February issue of
Hampe and colleagues used a total of 43 microsatellite markers covering chromosome 3 to genotype 353 sibling pairs with Crohn's disease and IBD. Marker order was defined by genetic and radiation hybrid techniques.
They found a significant peak single point logarithm of odds (LOD) score for Crohn's disease at D3S3591 and for IBD near D3S1304 (distal 3p) and D3S1283, providing linkage evidence for an IBD susceptibility locus on chromosome 3p (
Previous studies have identified other major IBD susceptibility loci on chromosomes 6, 12 and 16 and the publication of the human genome sequence may lead to the discovery of further IBD susceptibility loci.