For example, one association is with mutations in the XBP1 gene, which is involved in the unfolded protein response pathway of the endoplasmic reticulum. The gene variants of NOD2/CARD15 seem to be related with small-bowel involvement. Other well documented genes which increase the risk of developing Crohns disease are ATG16L1, IL23R, IRGM, and SLC11A1. There is considerable overlap between susceptibility loci for IBD and mycobacterial infections. Genome-wide association studies have shown that Crohns disease is genetically linked to coeliac disease.Crohns has been linked to the gene LRRK2 with one variant potentially increasing the risk of developing the disease by 70%, while another lowers it by 25%. The gene is responsible for making a protein, which collects and eliminates waste product in cells, and is also associated with Parkinsons disease. Immune system
There was a prevailing view that Crohns disease is a primary T cell autoimmune disorder; however, a newer theory hypothesizes that Crohns results from an impaired innate immunity. The later hypothesis describes impaired cytokine secretion by macrophages, which contributes to impaired innate immunity and leads to a sustained microbial-induced inflammatory response in the colon, where the bacterial load is high. Another theory is that the inflammation of Crohns was caused by an overactive Th1 and Th17 cytokine response.In 2007, the ATG16L1 gene was implicated in Crohns disease, which may induce autophagy and hinder the bodys ability to attack invasive bacteria.
Other conditions that can present similarly include irritable bowel syndrome and Behçets disease.There is no known cure for Crohns disease. Treatment options are intended to help with symptoms, maintain remission, and prevent relapse. In those newly diagnosed, a corticosteroid may be used for a brief period of time to rapidly improve symptoms, alongside another medication such as either methotrexate or a thiopurine used to prevent recurrence. Stopping smoking is recommended in people with Crohns disease. One in five people with the disease is admitted to the hospital each year, and half of those with the disease will require surgery for the disease at some point over a ten-year period. While surgery should be used as little as possible, it is necessary to address some abscesses, certain bowel obstructions, and cancers. Checking for bowel cancer via colonoscopy is recommended every few years, starting eight years after the disease has begun.Crohns disease affects about 3.2 per 1,000 people in Europe, North America, and the UK. It is less common in Asia and Africa. It has historically been more common in the developed world. Rates have, however, been increasing, particularly in the developing world, since the 1970s. Inflammatory bowel disease resulted in 47,400 deaths in 2015, and those with Crohns disease have a slightly reduced life expectancy. It tends to start in young adulthood, though it can occur at any age. Males and females are equally affected.