As many as 1 million Americans are affected by Crohn’s disease (CD). CD is a type of inflammatory bowel disease (IBD) that causes chronic inflammation in the gastrointestinal tract. While there are some treatments available, there is no cure for CD, and many patients may end up requiring bowel surgery to treat their condition. Additionally it can present differently from patient to patient — there is no one size fits all treatment to CD.
Thankfully, research by the University of North Carolina School of Medicine into the genes associated with CD may provide insight into different types of the condition. This is one of many studies that investigate different subtypes of Crohn’s, since the disease takes a different course in different people. The research study “Molecular classification of Crohn's disease reveals two clinically relevant subtypes” published in Gut looked at the expression and regulation of genes in patients with CD with inflamed and non-inflamed colon tissue, as well as a control group of healthy subjects.
What researchers discovered were two distinct subtypes of CD. One of the disease subtypes resembled healthy colon tissue, but gene expression in the second subtype resembled patterns seen in the ileum even though all samples were taken from the colon. Researchers theorized that the different gene subtypes might also represent different clinical courses of the disease.
In order to better study the role of the subtypes in the clinical course of CD, the researchers went on to look at 201 children who had recently been diagnosed with CD but who had not undergone any treatment or surgery for the condition. What they found were the same two subtypes — the subtype with tissue resembling the colon, and the subtype with tissue resembling the ileum (the third portion of the small intestine). The two subtypes were linked to very different courses of the disease, with the colon subtype being linked to more gut inflammation, rectal disease, and colon inflammation extreme enough to require surgery.
What this means for the future of CD treatments is the ability to distinguish the type of CD a patient has, which can help doctors tailor treatment. There are many other ways to categorize Crohn’s disease. This will likely provide an effective treatment more quickly, which may help prevent damage to the GI tract as well. More studies are needed to further establish these two subtypes in larger populations, develop easier diagnostic testing, and further follow the clinical course of each subtype.