Deletion of exons 16-17b of CFTR is frequently identified in Korean patients with cystic fibrosis

Abstract

Cystic fibrosis (MIM #219700) is one of the most common autosomal recessively inherited diseases in Caucasians and is caused by pathogenic variants in the cystic fibrosis transmembrane conductance regulator (CFTR) gene. However, this disease is much less frequent in Asian populations. Here, we performed a clinical characterization of, and genetic analysis of CFTR in, Korean patients with cystic fibrosis. Six Korean patients from five families (two females and four males: median age, 12.5 years) were enrolled. Clinical data were assessed by retrospective review of medical records. The genetic variants of CFTR were analysed by sequencing analysis and multiple ligation-dependent probe amplification (MLPA). Among the six patients, five had at least one allele with a deletion of exons 16-17b: four had a heterozygous deletion and one had a homozygous deletion. Six of 12 alleles (50%) showed 16-17b multi-exon deletion. All six patients had a classical cystic fibrosis phenotype and presented with chronic steatorrhea and malabsorption from infancy, resulting in growth failure and chronic recurrent respiratory symptoms, including chronic sinusitis, mucus plugging, and bronchiectasis. All patients survived with supportive care. Early diagnosis and management are important for improving the clinical outcomes of patients with cystic fibrosis. Because of the high frequency of multi- or single-exon deletions in CFTR, we suggest that molecular investigation for identifying exon deletions should be performed to establish an early confirmative diagnosis in Asian populations, including populations in Korea and Japan.