Clinical and genetic features of cystic fibrosis in Japan

Cystic fibrosis (CF) is an autosomal recessive disease caused by pathogenic variants in CF transmembrane conductance regulator (CFTR). While CF is the most common hereditary disease in Caucasians, it is rare in East Asia. In the present study, we have examined clinical features and the spectrum of CFTR variants of CF patients in Japan. Clinical data of 132 CF patients were obtained from the national epidemiological survey since 1994 and CF registry. From 2007 to 2022, 46 patients with definite CF were analyzed for CFTR variants. All exons, their boundaries, and part of promoter region of CFTR were sequenced and the presence of large deletion and duplications were examined by multiplex ligation-dependent probe amplification. CF patients in Japan were found to have chronic sinopulmonary disease (85.6%), exocrine pancreatic insufficiency (66.7%), meconium ileus (35.6%), electrolyte imbalance (21.2%), CF-associated liver disease (14.4%), and CF-related diabetes (6.1%). The median survival age was 25.0 years. The mean BMI percentile was 30.3%ile in definite CF patients aged