No association between the deltaF508 cystic fibrosis mutation and type 2 diabetes mellitus.

Cystic fibrosis (CF) is one of the most common recessively inherited disorders in Caucasian populations and is caused by mutations in the CF transmembrane conductance regulator (CFTR) gene. A three base deletion known as deltaF508 occurs on about 70%, of CF chromosomes and accounts for the high prevalence of the disease. Since type 2 diabetes mellitus occurs more frequently in relatives of patients with CF than in the normal population, we addressed the hypothesis whether heterozygosity for deltaF508 might be a genetic risk factor for type 2 diabetes. We screened 301 patients with type 2 diabetes mellitus which had been treated for at least three years from diagnosis by diet or oral antihyperglycemic agents. Healthy controls (n = 282) had no family history for diabetes. The genotype distribution did not differ significantly between patients with type 2 diabetes (2% heterozygotes) and controls (3% heterozygotes). According to these results, we conclude, that the deltaF508 mutation in its heterozygous form does not represent a major genetic risk factor for type 2 diabetes mellitus.