A study of the gene frequencies of CARD15/NOD2 gene variants has suggested that Finnish people with inflammatory bowel disease (IBD) may have different variants from those predisposing to coeliac disease (CD) or IBD in Westerners.

More research will be needed to locate the other gene polymorphisms. What the study has shown—despite low frequency in the genetically homogeneous Finnish population—is that heterozygposity for the three main variants R702W, G908R, and 1007fs overall is significantly higher for patients with CD than controls or patients with ulcerative colitis (UC) (8.7% v 3.5%). The 1007fs variant alone was more common in patients with CD than controls (4.8% v 1.7%) and more frequent in familial than sporadic CD (10.9% v 3.5%).

Patients with CD had one or more of the variants (15.5%) more commonly than patients with UC (9.1%) or controls (6.7%). Among these CD patients the ileum was more often affected than among the other CD patients (90% v 73%) and their disease was more invasive or complicated by strictures (88% v 56%). Significant differences in treatment between these two groups were not to blame.

The study screened patients and controls for the main CARD15 variants. There were 198 patients with sporadic CD; 46 probands with familial CD and 27 probands with CD from mixed IBD families; 99 unrelated patients with UC; and 300 unrelated healthy controls.

The study was intended to determine any links between the main CARD15 variants and familial IBD or complex forms of CD in Finnish patients.