Relative frequencies of cystic fibrosis mutations in The Netherlands as an illustration of significant regional variation in a small country

Cystic fibrosis (CF) is one of the most common autosomal recessive disorders in white populations. Significant regional differences in CF mutations among affected individuals have been reported. We have studied the geographic distribution of the relative frequencies of the three most common Dutch CF mutations, Delta F508, A455E, and G542X, by analyzing data on area of residence of CF patients. Significantly higher relative frequencies of the A455E mutation and the G542X mutation were observed in the South-West and the South-East, respectively. A uniform distribution of relative frequencies was found for the Delta F508 mutation. The results of our study show that, even in a small country such as The Netherlands, certain CF mutations may be more common in one region than in another.