- Diarrhea (HP:0002014): Abnormally increased frequency (usually defined as three or more) loose or watery bowel movements a day. Evidence: TAS. (OMIM:266600)
- Inflammation of the large intestine (HP:0002037): Inflammation, or an inflammatory state in the large intestine. Evidence: TAS. (OMIM:266600)
- Intestinal obstruction (HP:0005214): Blockage or impairment of the normal flow of the contents of the intestine towards the anal canal. Evidence: TAS. (OMIM:266600)
- Ulcerative colitis (HP:0100279): A chronic inflammatory bowel disease that includes characteristic ulcers, or open sores, in the colon. The main symptom of active disease is usually constant diarrhea mixed with blood, of gradual onset and intermittent periods of exacerbated symptoms contrasting with periods that are relatively symptom-free. In contrast to Crohn's disease this special form of colitis begins in the distal parts of the rectum, spreads continually upwards and affects only mucose and submucose tissue of the colon. Evidence: TAS. (OMIM:266600)
- Crohn's disease (HP:0100280): A chronic granulomatous inflammatory disease of the intestines that may affect any part of the gastrointestinal tract from mouth to anus, causing a wide variety of symptoms. It primarily causes abdominal pain, diarrhea which may be bloody, vomiting, or weight loss, but may also cause complications outside of the gastrointestinal tract such as skin rashes, arthritis, inflammation of the eye, tiredness, and lack of concentration. Crohn's disease is thought to be an autoimmune disease, in which the body's immune system attacks the gastrointestinal tract, causing inflammation. Evidence: TAS. (OMIM:266600)
- Aphthous ulcer (HP:0032154): Oral aphthous ulcers typically present as painful, sharply circumscribed fibrin-covered mucosal defects with a hyperemic border. Evidence: TAS. (OMIM:266600)
- Polygenic inheritance (HP:0010982): A mode of inheritance that depends on a mixture of major and minor genetic determinants possibly together with environmental factors. Diseases inherited in this manner are termed complex diseases. Evidence: TAS. (OMIM:266600)
- Weight loss (HP:0001824): Reduction of total body weight. Evidence: TAS. (OMIM:266600)
- Growth delay (HP:0001510): A deficiency or slowing down of growth pre- and postnatally. Evidence: TAS. (OMIM:266600)
- Abdominal pain (HP:0002027): An unpleasant sensation characterized by physical discomfort (such as pricking, throbbing, or aching) and perceived to originate in the abdomen. Evidence: TAS. (OMIM:266600)
- Recurrent aphthous stomatitis (HP:0011107): Recurrent episodes of ulceration of the oral mucosa, typically presenting as painful, sharply circumscribed fibrin-covered mucosal defects with a hyperemic border. Evidence: TAS. (OMIM:266600)
- Intestinal fistula (HP:0100819): An abnormal connection between the gut and another hollow organ, such as the bladder, urethra, vagina, or other regions of the gastrointestinal tract. Evidence: TAS. (OMIM:266600)
These phenotypes are associated with the disease inflammatory bowel disease 1 (OMIM:266600).