Researchers from Oxford and London, England, conducted a detailed genotype-phenotype analysis of patients with Crohn's disease.
Chromosome 16 and the HLA region on chromosome 6 have been implicated in susceptibility to Crohn's disease.
Mutations in the NOD2/CARD15 gene, recently identified on chromosome 16, have been associated with disease overall, but are found in only 25% of patients. No data regarding their contribution to specific disease subtypes exist.
A total of 244 white patients with Crohn's disease, recruited from a single center in the United Kingdom, were studied.
All patients were rigorously phenotyped and followed-up for a median time of 16 years.
By using linkage disequilibrium mapping, the authors studied 340 polymorphisms in 24 HLA genes and 3 NOD2/CARD15 polymorphisms.
| NOD2/CARD15 mutations determined ileal disease only.
The team found that NOD2/CARD15 mutations determined ileal disease only.
They also confirmed that alleles on specific long-range HLA haplotypes determine overall susceptibility.
In addition, they described novel genetic associations with susceptibility, location, and behavior of Crohn's disease.
Tariq Ahmad, of the Radcliffe Infirmary, Oxford, concluded on behalf of the group, "The clinical pattern of Crohn's disease may be defined by specific genotypes.
"This study may provide the basis for a future molecular classification of disease."