Misdiagnosing cystic fibrosis in the era of gene analysis: case reports.

We present a scenario of how gene analysis plays a confusing role in the diagnosis of cystic fibrosis (CF). One of the two siblings we are presenting here was initially misdiagnosed as having CF, based on the two CF gene mutations identified by gene analysis. A CF gene study on the other sibling years later, however, led to further investigation and eventually to a change of diagnosis. As interesting and important as gene analysis is in CF, one must always look at each patient in the big picture. Included in the picture, in addition to the state-of-the-art genotype, is the phenotype, or (to simplify) the back-to-basic clinical manifestations.