No association between the ΔF508 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 ΔF508 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 ΔF508 might be a genetic risk factor for type diabetes. We screened 301 patients with type 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 ΔF508 mutation in its heterozygous form does not represent a major genetic risk factor for type 2 diabetes mellitus.