Analyzing DNA from buccal cells is a reliable method for the exclusion of cystic fibrosis. Results of a pilot study.

PURPOSE: In children there is frequently a reason to exclude cystic fibrosis. Sweat testing is used for this. Because sweat testing has some disadvantages we investigated whether analyzing DNA for the local most common CFTR mutations, harvested from buccal cells, is reliable as a method to exclude cystic fibrosis. METHODS: In patients in whom a sweat test had been ordered during the period January 1, 2002 to December 31, 2004, we harvested buccal cell DNA for analysis. When blood was available, DNA from leukocytes was also analyzed. RESULTS: A total of 73 sweat tests were ordered during the two-year study period, mostly because of recurrent pulmonary infections (36; 49%), failure to thrive (20; 27%) and chronic diarrhea (10, 14%). In 70, children the results of the sweat test were normal, in three patients the results were borderline. Sixty buccal smears were analyzed and no patient was homozygous for cystic fibrosis, two were heterozygous for cystic fibrosis. In none of the children the diagnosis of cystic fibrosis was established. CONCLUSION: Analyzing DNA in cells, harvested from the buccal cells, is a reliable alternative to exclude cystic fibrosis. It is safe, simple, and child-friendly.