A Swedish research team reported the first twin study in inflammatory bowel disease in 1988.
In this study, the same researchers followed-up the twins to investigate new cases of inflammatory bowel disease, and Crohn’s characteristics using the Vienna classification.
The team's findings are published in the June issue of Gastroenterology
|Pair concordance in monozygotic twins was 50% for Crohn’s disease.|
The team used the official Swedish population register, and cause of death register to search for the twins. All living patients were interviewed.
They found that 3 monozygotic twins, who had earlier been classified as healthy, had been diagnosed with inflammatory bowel disease. Of these, 2 had ulcerative colitis and 1 Crohn’s disease. Retrospectively, all 3 were symptomatic at the original survey.
The researchers found that this new data changed the pair concordance in monozygotic twins from 6% to 19% in ulcerative colitis, and from 44% to 50% in Crohn’s disease.
The team identified a high level of concordance regarding age at diagnosis, disease location, and disease behavior in monozygotic twin pairs with Crohn’s disease.
They found that 7 out of 9 pairs were identical in ≥3 disease characteristics, compared with an expected number of 1.5.
Dr Jonas Halfvarson's team concluded, "This study confirms that the genetic influence is stronger in Crohn’s disease than in ulcerative colitis".
"A remarkable phenotype similarity within concordant pairs with Crohn’s disease was found using the Vienna classification".