The etiology of Crohn’s disease (CD) remains an enigma. The variability of disease prevalence in different racial groups and its familial aggregation reflect significant influence of genetic factors in the susceptibility to CD. Studies of CD in the immigrant Chinese population in Vancouver suggest that the rarity of CD in Chinese residents in Asia may be modified by an increased susceptibility to the disease when they emigrate to North America. Nevertheless, the prevalence rate of CD in Chinese remains low, and familial occurrence of CD has not been reported previously in Chinese. This is a report of CD in a Chinese family, affecting a daughter and her mother. A 35-year-old Chinese woman first developed abdominal cramps and bowel urgency with loose stools accompanied by blood and mucus, 16 years after she emigrated to Canada from Hong Kong. Air-contrast barium enema showed segmental stenoses with irregular nodular mucosa involving the sigmoid, proximal transverse, and ascending colon, and a contracted cecum. Intermittent exacerbations have responded to 5-aminosalicylic acid (5-ASA). At colonoscopy 6 years after the initial diagnosis, there was also involvement of the terminal ileum. She has been followed up for 10 years. Five years after her diagnosis, her mother was also shown to have CD of the transverse colon, ascending colon, and cecum, diagnosed at age 69, 9 years after she emigrated to Canada. She presented with mid-abdominal pain, slight bowel urgency, and narrowed calibre stools. Air-contrast barium enema showed absence of haustral markings throughout the right colon, and a persistent 7.5 cm long narrowed segment in the distal transverse colon. Colonoscopy revealed active colitis in the involved segments. In the 5 years since the diagnosis, her disease has been stable despite her intolerance of 5-ASA and sulfasalazine, both causing distressing diarrhea.

Development of CD among first degree relatives separated by a generation suggests that genetic predisposition rather than shared environmental influences is the basis of the familial occurrence of CD in these 2 patients. The cases strongly indicate that CD in Chinese patients also has a significant genetic basis.

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