J Korean Med Sci 2006; 21: 563-6 ISSN 1011-8934 Copyright The Korean Academy of Medical Sciences Report of a Korean Patient with Cystic Fibrosis, Carrying Q98R and Q220X Mutations in the CFTR Gene Although cystic fibrosis (CF) is one of the most frequently seen autosomal-reces- sive disorders in Caucasians, it is extremely rare in the Korean population. Recently, a 15-yr-old Korean boy was admitted to our hospital complaining of coughing, spu- tum, and exertional dyspnea. Chest radiographs and computed tomographic chest and paranasal sinus scans revealed diffuse bronchiectasis and pansinusitis. Pul- monary function tests revealed severe obstructive impairment. The average sweat chloride concentrations on both of the patients’ forearms were 63.0 mM/L (reference limit: <40 mM/L). Upon mutation analysis, two different mutations (Q98R and Q220X) were identified in the cystic fibrosis transmembrane conductance regulator gene, both of which had been previously detected in CF patients, one from France and the other from England. As CF is quite rare in Korea, the diagnosis of CF in this patient might be delayed. Therefore, we recommend that a diagnosis of CF should be suspected in patients exhibiting unexplained chronic respiratory symptoms. Key Words : Cystic Fibrosis; Cystic Fibrosis Transmembrane Conductance Regulator, CFTR; Mutation Won-Jung Koh, Chang-Seok Ki*, Jong-Won Kim*, Jeong-Ho Kim , Seong Yong Lim Division of Pulmonary and Critical Care Medicine, Department of Medicine and Department of Laboratory Medicine*, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul; Department of Laboratory Medicine , Yongdong Severance Hospital, Yonsei University College of Medicine, Seoul; Division of Pulmonary and Critical Care Medicine , Department of Medicine, Kangbuk Samsung Hospital, Sungkyunkwan University School of Medicine, Seoul, Korea Received : 18 February 2005 Accepted : 19 May 2005 Address for correspondence Chang-Seok Ki, M.D. Department of Laboratory Medicine, Samsung Medical Center, Sungkyunkwan University School of Medicine, 50 Irwon-dong, Gangnam-gu, Seoul 135-710, Korea Tel : +82.2-3410-2710, Fax : +82.2-3410-2719 E-mail : changski@skku.edu INTRODUCTION Cystic fibrosis (CF; MIM 219700) is a lethal disease, which is induced by mutations in the cystic fibrosis transmembrane conductance regulator (CFTR) gene on chromosome 7q31. CF is one of the most frequently-occurring autosomal reces- sive disorders in Caucasians, with an incidence of 1 in every 2,000 to 3,000 (1). However, CF is quite rare in the Asian population that an epidemiological study in the Japanese population revealed the incidence of CF being about 1 in 350,000 (2, 3). CF is also extremely rare in the Korean pop- ulation and there have been only a few reports of this condi- tion thus far (4-6). Here, we report a Korean patient with CF, who was diagnosed by both a sweat chloride test and genetic analysis of the CFTR gene. CASE REPORT A 15-yr-old boy was admitted to the Samsung Medical Center, complaining of chronic productive cough and dysp- nea without any gastrointestinal symptoms. During the first 563 decades of life, the patient had been treated for several episodes of bronchiolitis and pneumonia, necessitating frequent hos- pital admission. Six years prior to the current hospitalization, the patient’s respiratory symptoms became aggravated. He was admitted to a civil hospital for the treatment of pulmonary tuberculosis, and received antituberculosis drug therapy for 12 months. He developed frequent rhinorrhea and nasal stuffi- ness, and underwent sinus surgery at the age of twelve. His respiratory symptoms progressively worsened, and he was diagnosed with bronchiectasis three years ago. He had a 25- yr-old brother and a 24-yr-old sister, with an unremarkable past and a current medical history. On admission, the patient’s blood pressure was 128/69 mmHg, heart rate 80 beats per minute, respiratory rate 20 breaths per minute, body temperature 36.0℃, height 174 cm, and he weighed 53.6 kg. He was also determined to exhibit 96 percent oxygen saturation when breathing room air. Upon physical examination, diffuse crackles and rhonchi were heard throughout the patient’s lungs, with intermittent wheezes. Chest radiographs and computed tomographic (CT) scans of the chest, performed without intravenous contrast mate-