Cystic fibrosis with homozygous R553X mutation in a Taiwanese child.

It has been reported that cystic fibrosis is very rare in Asians, and its clinical expression and genetic mutations are different from those found in Caucasians. We report the case of a boy who had chronic diarrhea with failure to thrive and frequent respiratory tract infections beginning at the age of 2 months. He developed bronchiectasis with chronic severe hypoxemia and pancreatic insufficiency by the age of 3 years and 5 months, which raised the consideration of cystic fibrosis. DNA analysis revealed a homozygous R553X mutation, and both his parents were subsequently proven to be R553X carriers. This case is the first report in a Taiwanese with cystic fibrosis attributable to a mutation commonly seen in Caucasians. However, the age of onset was much younger and the clinical course was more severe than those associated with Western patients. We reviewed the eight reported Taiwanese patients with cystic fibrosis, including the present case. We believe that the incidence of cystic fibrosis in Taiwan may be underestimated. Both genetic and environmental factors may play a role in the phenotypic disparity between Asians and Caucasians.