Hidaka Kouko, Hayashi Shinichrou, Nakakuki Miyuki, Naruse Satoru, Ishiguro Hiroshi
Respiratory Medicine, National Hospital Organization Kokura Medical Center, Kitakyushu, JPN.
Respiratory Medicine, Kouhoukai Takagi Hospital, Okawa, JPN.
Cureus. 2025 Jun 25;17(6):e86774. doi: 10.7759/cureus.86774. eCollection 2025 Jun.
Cystic fibrosis (CF) is caused by mutations in the cystic fibrosis transmembrane conductance regulator () gene, which encodes a chloride ion channel, and occurs frequently in the Caucasian population but rarely in Asia. Elevated sweat chloride using the sweat test is a gold standard for CF diagnosis, but it is not readily available in Japan. A 22-year-old man, who had past histories characteristic of CF, such as recurrent pneumonia, sinusitis, and pneumothorax, was referred to our hospital due to bronchiectasis and bronchial asthma. Examination revealed severely impaired lung dysfunction and abnormal chloride ion concentration in the sweat test corresponding to intermediate values, indicative of CFTR dysfunction. Analysis of his gene failed to detect any CF-causing variants, but showed the haplotype known to express a smaller amount of intact CFTR protein and associated with several pulmonary diseases. A diagnosis was made of bronchiectasis caused by CFTR dysfunction, and he was treated with inhalation solution of dornase alfa, hypertonic saline solution, and tobramycin at the age of 25; however, his lung deteriorated, and he died at the age of 32. As a result of retrospective reviewing of the lung images and functions from childhood, we found that pneumonia in childhood developed to cystic bronchiectasis in adulthood, and obstructive ventilator dysfunction already existed at the age of 13, progressing to the devastating decline of lung function as he grew. Pulmonary disease due to CFTR dysfunction in Japan has a poor prognosis because of challenges to access to the sweat test and a lack of recognition for CF.
囊性纤维化（CF）由囊性纤维化跨膜传导调节因子（CFTR）基因突变引起，该基因编码一种氯离子通道，在白种人人群中常见，在亚洲人群中罕见。使用汗液试验检测汗液中氯离子升高是CF诊断的金标准，但在日本难以获得该检测。一名22岁男性，有CF的典型病史，如反复肺炎、鼻窦炎和气胸，因支气管扩张和支气管哮喘转诊至我院。检查发现肺功能严重受损，汗液试验中氯离子浓度异常，对应中间值，提示CFTR功能障碍。对其CFTR基因分析未检测到任何导致CF的变异，但显示出已知表达较少量完整CFTR蛋白且与多种肺部疾病相关的单倍型。诊断为CFTR功能障碍导致的支气管扩张，他在25岁时接受了 Dornase alfa吸入溶液、高渗盐溶液和妥布霉素治疗；然而，他的肺部病情恶化，32岁时死亡。通过回顾其儿童时期的肺部影像和功能，我们发现儿童期肺炎发展为成人期囊性支气管扩张，13岁时已存在阻塞性通气功能障碍，随着年龄增长肺功能急剧下降。由于在日本进行汗液试验存在困难以及对CF缺乏认识，CFTR功能障碍导致的肺部疾病预后较差。
