This is based on the individuals and how the defective connective tissue (collagen) presents. Those with EDS can have manifestations from mouth to anus, some of which are benign, and others can be lethal. Differential diagnoses should always be broad, and treatment must take into consideration not only the known complications of EDS but also the propensity of the particular patient to manifest them.
Structural abnormalities of the gastrointestinal tract are common in EDS due to the fragility and extensibility of the tissue. Hiatal hernia, gastric, duodenal and colonic diverticula may occur. Other features which have been demonstrated are visceroptosis (protrusion of the contents of the abdomen), slow motility, delayed gastric emptying, gastric atony (lack of contraction of the stomach), recurrent abdominal pain, gastroesophageal reflux disease (GERD), megaoesophagus, irritable bowel, constipation, diarrhea, megacolon, bleeding, ruptures, and perforations.
Solomon JA et al. "GI Manifestations of EDS." Am J Gastroenterol 1996 Nov; 91 (11): 2282–8. Available from http://bit.ly/UzmCCX.