Researchers from Los Angeles, California, USA, investigated whether NOD2 gene mutations are associated with distinct phenotypic expressions of Crohn's disease (CD).
Two cohorts of patients referred to an inflammatory bowel disease center (n = 142 collected between 1993 and 1996; n = 59 collected between 1999 and 2001) were included in the study.
Each individual was genotyped for 3 single nucleotide variants of NOD2 - R675W, G881R, and 3020insC.
They were also phenotyped for disease behavior, disease location, and serum immune markers.
Univariate analysis showed that CD-associated NOD2 variants were significantly associated with fibrostenosing disease in each of the cohorts.
|NOD2 mutation present:|
Fibrostenosing disease: 46%
Non-fibrostenosing disease: 24%
| Gastroenterology |
When the authors analyzed both cohorts together, the association between NOD2 variants and fibrostenosing disease was found to be more significant.
These relationships were observed in both Jews and non-Jews.
The team discovered that 46% of patients with fibrostenosing disease carried at least 1 of these alleles, compared with only 24% of patients without fibrostenosing disease (odds ratio, 2.8).
Multivariate and conditioning analyses showed a primary association between NOD2 allelic variants and fibrostenosing disease, but not with small-bowel disease.
Dr Maria T. Abreu, of the Cedars-Sinai Medical Center, Los Angeles, concluded on behalf of her colleagues, "In this study, data suggest that variation in NOD2 contributes to the occurrence of fibrostenotic CD of the small bowel."