Crohn’s disease is a chronic relapsing inflammatory disorder of the intestinal tract that affects an estimated 0.15% of people in the developed world. Common symptoms include abdominal pain and diarrhea, but the disorder is often associated with debilitating clinical complications. Researchers from the University of Liège, Belgium, have now uncovered an important clue to the susceptibility of individuals to this disease.

In a genome-wide association study with more than 300,000 single nucleotide polymorphisms (SNPs) – DNA sequence variations occurring when a single nucleotide in the genome differs between members of a species – Cécile Libioulle et al. identified a new susceptibility locus for Crohn’s disease. Their results are published online in the open-access journal PLoS Genetics.

Recent advances in SNP genotyping technology have allowed systematic association scanning of the entire genome for the detection of novel susceptibility loci – fixed positions on a chromosome, such as the position of a gene. Libioulle and colleagues applied this approach to Crohn’s disease and identified the key locus on chromosome 5.

Individual susceptibility to many common diseases, including Crohn’s disease, is determined by a combination of environmental and genetic factors and identifying these genetic risk factors is one of the most important objectives of modern medical genetics, potentially paving the way towards personalized medicine and drug target identification.

CITATION: Libioulle C, Louis E, Hansoul S, Sandor C, Farnir F, et al. (2007) Novel Crohn disease locus identified by genome-wide association maps to a gene desert on 5p13.1 and modulates expression of PTGER4. PLoS Genet 3(4): e58. doi:10.1371/journal.pgen.0030058

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