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Diseases

Genetic and Rare Diseases Information Center (GARD)

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Crohn's disease

*


* Not a rare disease
Other Names for this Disease
  • Enteritis
  • Granulomatous colitis
  • Granulomatous enteritis
  • Ileitis
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Overview



What is Crohn's disease?

What are the signs and symptoms of Crohn's disease?

What causes Crohn's disease?

Is Crohn's disease inherited?

How is Crohn's disease diagnosed?


How might Crohn's disease be treated?


What is Crohn's disease?

Crohn's disease is a type of inflammatory bowel disease (IBD), the general name for conditions that cause inflammation in the intestines. Common signs and symptoms include abdominal pain and diarrhea. Bleeding from the rectum, weight loss, joint pain, skin problems and fever may also occur. Other problems can include intestinal blockage and malnutrition. Crohn's disease can occur in people of all age groups but is most often diagnosed in young adults. The exact cause is unknown, but is thought to involve both genetic and environmental factors. It appears to run in some families. Treatment is aimed at relieving symptoms and reducing inflammation, but some people require surgery. Quitting smoking can also improve the symptoms of Crohn’s disease.[1][2]
Last updated: 11/15/2012

What are the signs and symptoms of Crohn's disease?

Crohn's disease causes inflammation of the digestive or gastrointestinal (GI) tract. It usually occurs in the lower part of the small intestine, called the ileum, but it can affect any part of the digestive tract, from the mouth to the anus. The inflammation extends deep into the lining of the affected organ, which can cause abdominal pain and diarrhea.[1] Affected individuals may also have loss of appetite, weight loss, and fever.[3]

About one-third of individuals with Crohn's disease have symptoms outside of the intestines, which may include arthritis, uveitis (inflammation of the covering of the eye), skin lesions, and sacroilitis (inflammation of the large joints of the tail bone and pelvis).[4]

Symptoms of Crohn's disease may range from mild to severe. Most people will go through periods in which the disease flares up and causes symptoms, alternating with periods when symptoms disappear or decrease. People with Crohn’s disease who smoke tend to have more severe symptoms and more complications. In general, people with Crohn's disease lead active and productive lives.[1][4]
Last updated: 11/15/2012

What causes Crohn's disease?

The exact cause of Crohn's disease is not known, but it appears to be a multifactorial condition. This means that both genetic and environmental factors likely interact to predispose an individual to being affected. Studies suggest that Crohn's disease may result from a combination of certain genetic variations, changes in the immune system, and the presence of bacteria in the digestive tract.[3]

Recent studies have found that variations in specific genes, including the ATG16L1, IL23R, IRGM, and NOD2 genes, influence the risk of developing Crohn's disease. These genes provide instructions for making proteins that are involved in immune system function. Variations in any of these genes may disrupt the ability of intestinal cells to respond to bacteria, leading to chronic inflammation and thus the signs and symptoms of the condition. There may also be genetic variations in regions of chromosome 5 and chromosome 10 that contribute to an increased risk to develop Crohn's disease.[3]
Last updated: 10/15/2012

Is Crohn's disease inherited?

Crohn's disease, like most other autoimmune diseases, is thought to be a multifactorial condition. This means it is likely associated with the effects of multiple genes, in combination with lifestyle and environmental factors.[5] Once an autoimmune disease is present in a family, other relatives may be at risk to develop the same autoimmune disease, or a different autoimmune disease. However, if an autoimmune diseases such as Crohn's disease occurs in a family, it does not necessarily mean that relatives will develop an autoimmune disease.[6] Having an affected family member means that there may be a genetic predisposition in the family that could increase an individual's chance of developing an autoimmune disease. Thus, having an affected family member is considered a risk factor for Crohn's disease.[7]
Last updated: 10/15/2012

How is Crohn's disease diagnosed?

A variety of tests are used to diagnose and monitor Crohn’s disease. A combination of tests is often needed because some symptoms of the condition are similar to other intestinal disorders such as irritable bowel syndrome and to another type of inflammatory bowel disease (IBD) called ulcerative colitis.[1] Tests used to narrow down the diagnosis may include blood tests, tissue tests, ultrasound, x-rays, CT scan, and/or endoscopy. A proper diagnosis also involves identifying the extent and severity of disease as well as any related complications.[8]
Last updated: 10/15/2012

How might Crohn's disease be treated?

For information on the treatment of Crohn's disease, visit the following links:

National Digestive Diseases Information Clearinghouse: 
http://digestive.niddk.nih.gov/ddiseases/pubs/crohns_ez/index.htm#treat

Crohn's & Colitis Foundation of America: 
http://www.ccfa.org/what-are-crohns-and-colitis/what-is-crohns-disease/crohns-treatment-options.html

Complementary and Alternative Medicine (CAM) for Crohn's disease from the Crohn's & Colitis Foundation of America: 
http://www.ccfa.org/resources/complementary-alternative.html

Last updated: 11/15/2012

References
  1. Crohn's disease. National Digestive Diseases Information Clearinghouse (NIDDC). 2006; http://digestive.niddk.nih.gov/ddiseases/pubs/crohns/index.htm. Accessed 7/29/2010.
  2. David B. Sachar, Aaron E. Walfish. Crohn's Disease. Merck Manuals. Aigust 2006; http://www.merckmanuals.com/home/digestive_disorders/inflammatory_bowel_diseases_ibd/crohns_disease.html?qt=&sc=&alt=.
  3. Crohn disease. Genetics Home Reference. August 2007; http://ghr.nlm.nih.gov/condition/crohn-disease. Accessed 10/15/2012.
  4. Cummings S, Rubin D. The Complexity and Challenges of Genetic Counseling and Testing for Inflammatory Bowel Disease. Journal of Genetic Counseling. December 2006;
  5. What are complex or multifactorial disorders?. Genetics Home Reference. October 8, 2012; http://ghr.nlm.nih.gov/handbook/mutationsanddisorders/complexdisorders. Accessed 10/15/2012.
  6. Department of Human Genetics. Autoimmune disorders. Emory University School of Medicine. 2004; http://www.genetics.emory.edu/pdf/Emory_Human_Genetics_Autoimmune_Disorders.pdf. Accessed 2/7/2012.
  7. Crohn Disease. Genetics Home Reference (GHR) . August 2007; http://ghr.nlm.nih.gov/condition=crohndisease. Accessed 2/7/2012.
  8. Diagnosing Crohn's Disease and Ulcerative Colitis. Crohn's & Colitis Foundation of America. May 31, 2010; http://www.ccfa.org/resources/diagnosing-crohns-uc.html. Accessed 10/15/2012.