Differences in disease severity of F508del homozygotes across European countries

Introduction: Significant phenotypic variation occurs even among patients carrying identical CFTR genotype. This suggests that other factors, such as modifier genes and environmental factors, contribute to the determination of CF severity. The aim of this study is to compare clinical characteristics of patients carrying the common genotype (F508del/F508del) across European countries. Patients: We analysed data from 6663 F508del homozygous patients from 15 countries, included in the European CF Registry in the year 2007. The frequency of F508del homozygotes varies from 70% in Denmark to 11% in Israel. We evaluated differences in clinical characteristics of CF including pulmonary function, anthropometric data, complications, and therapy. Results: Statistically significant (p<0.01) differences were found across countries in median FEV1% (59 1291%), proportion of patients with BMI