Cystic fibrosis (CF) is a fatal autosomal-recessive disease caused by mutations in the CF transmembrane conductance regulator (CFTR) gene. CF is characterized by recurrent pulmonary infection with obstructive pulmonary disease. CF is common in the Caucasian population but is rare in the Chinese population. The symptoms of early-stage CF are often untypical and may sometimes manifest as Bartter syndrome (BS)-like hypokalemic alkalosis. Therefore, the ability of doctors to differentiate CF from BS-like hypokalemic alkalosis in Chinese infants is a great challenge in the timely and accurate diagnosis of CF. In China, sporadic CF has not been diagnosed in children younger than three years of age to date. Three infants, who were initially admitted to our hospital over the period of June 2013 to September 2014 with BS-like hypokalemic alkalosis, were diagnosed with CF through exome sequencing and sweat chloride measurement. The compound heterozygous mutations of the CFTR gene were detected in two infants, and a homozygous missense mutation was found in one infant. Among the six identified mutations, two are novel point mutations (c.1526G > C and c.3062C > T) that are possibly pathogenic. The three infants are the youngest Chinese patients to have been diagnosed with sporadic CF at a very early stage. Follow-up examination showed that all of the cases remained symptom-free after early intervention, indicating the potential benefit of very early diagnosis and timely intervention in children with CF. Our results demonstrate the necessity of distinguishing CF from BS in Chinese infants with hypokalemic alkalosis and the significant diagnostic value of powerful exome sequencing for rare genetic diseases. Furthermore, our findings expand the CFTR mutation spectrum associated with CF.
Alkalosis ; complications ; Bartter Syndrome ; China ; Cystic Fibrosis ; diagnosis ; genetics ; Cystic Fibrosis Transmembrane Conductance Regulator ; genetics ; Diagnosis, Differential ; Exome ; Female ; Humans ; Hypokalemia ; complications ; Infant ; Male ; Mutation

Child ; Cystic Fibrosis ; diagnosis ; diagnostic imaging ; genetics ; Female ; Genetic Testing ; Humans ; Radiography ; Sweating

Cystic fibrosis (CF) is an autosomal recessive disease that is very rare in Asians: only a few cases have been reported in Korea. We treated a female infant with CF who had steatorrhea and failure to thrive. Her sweat chloride concentration was 102.0 mM/L. Genetic analysis identified two novel mutations including a splice site mutation (c.1766+2T>C) and a frameshift mutation (c.3908dupA; Asn1303LysfsX6). Pancreatic enzyme replacement and fat-soluble vitamin supplementation enabled the patient to get a catch-up growth. This is the first report of a Korean patient with CF demonstrating pancreatic insufficiency. CF should therefore be considered in the differential diagnosis of infants with steatorrhea and failure to thrive.
Alternative Splicing ; Base Sequence ; Cystic Fibrosis/complications/diagnosis/*genetics ; Cystic Fibrosis Transmembrane Conductance Regulator/*genetics ; Diagnosis, Differential ; Exocrine Pancreatic Insufficiency/complications/diagnosis/*genetics ; Female ; Frameshift Mutation ; Humans ; Infant ; Republic of Korea ; Steatorrhea/diagnosis

OBJECTIVECystic fibrosis (CF) is rare in Chinese mainland. We present two cases of CF patients diagnosed by gene analysis. Their clinical manifestations and genetic mutation features are analyzed in this article. It will be of special interest to pediatricians in recognition of CF.

METHODThe clinical material of two CF patients who were diagnosed by gene analysis was retrospectively analyzed.

RESULTThe first patient is a 13-year-old girl. She had a complaint of recurrent fever and cough for 6 months, expectoration for 2 months and hemoptysis for 20 days. After 3 months of her birth, she was operated on for bullae of lung. She was susceptible to upper respiratory tract infection. There was no family history of recurrent wheeze and other special diseases. Aspergillus fumigatus specific IgE was at grade 3 and aspergillus fumigatus IgG was high. Pseudomonas aeruginosa was positive in sputum culture. Sweat testing was performed and Na+ was higher. Pulmonary CT indicated bronchiectasis. Nasal sinus CT showed optical density of soft tissue within maxillary sinus and chronic bilateral sinusitis. The electron microscopy of cilia suggested immobile cilia syndrome. A heterozygotic mutation (263T > G, 2909G > A) was found after CFTR genetic mutation analysis. Both her parents were carriers. She was treated with inhalation of nebulized hypertonic saline and postural drainage for a long time. And she got better during a follow up period of 1 year. The second patient was a 10-year-old girl who complained of recurrent expectoration for 3 years and shortness of breath for half a year. She had a history of sinusitis and steatorrhea. The family history was normal. Both the lipase and insulin level in blood serum was lower.Pseudomonas aerugino and Aspergillus fumigatus were both positive in sputum culture. Aspergillus fumigatus IgE was normal. Pulmonary CT indicated bronchiolitis and bronchiectasis. Nasal sinus CT showed bilateral maxillary sinusitis. CFTR genetic mutation analysis revealed a homozygous mutation (3196C > T). Her parents and relatives did not participate in this study. Unfortunately, this child died of respiratory failure 3 months after discharge.

CONCLUSIONCFTR gene mutation was a main cause of CF. Common symptoms are those of bronchiectasis, pancreatitis and sinusitis. The two Chinese patients were diagnosed by gene analysis. One had a heterozygous mutation (263T > G, 2909G > A) and the other had a homozygous mutation (3196C > T), not ΔF508 which is common in western countries.

Adolescent ; Asian Continental Ancestry Group ; genetics ; Bronchiectasis ; etiology ; genetics ; Child ; Cystic Fibrosis ; complications ; diagnosis ; genetics ; Cystic Fibrosis Transmembrane Conductance Regulator ; genetics ; DNA Mutational Analysis ; Female ; Heterozygote ; Homozygote ; Humans ; Mutation ; Retrospective Studies ; Sinusitis ; etiology ; genetics

Cystic fibrosis (CF) is an autosomal recessive disorder usually found in populations of white Caucasian descent. CF is caused by mutations in the Cystic Fibrosis Transmembrane conductance Regulator (CFTR) gene. A 5-yr-old Korean girl was admitted complaining of coughing and greenish sputum. Chest radiographs and computed tomographic (CT) scan revealed diffuse bronchiectasis in both lungs. The patient had chronic diarrhea and poor weight gain, and the abdominal pancreaticobiliary CT scan revealed atrophy of the pancreas. Finally, CF was confirmed by the repeated analysis of the quantitative pilocarpine iontophoresis test. The chloride concentration of sweat samples taken from both forearms of the pateint was an average of 88.7 mM/L (normal value <40 mM/L). After a comprehensive search for mutations in the CFTR gene, the patient was found to carry the non-synonymous L441P mutation in one allele. Molecular physiologic analysis of the L441P mutation of CFTR revealed that the L441P mutation completely abolished the CFTR Cl- channel activity by disrupting proper protein folding and membrane trafficking of CFTR protein. These results confirmed the pathogenicity of the L441P mutation of CFTR circulating in the Korean population. The possibility of CF should be suspected in patients with chronic bronchiectasis, although the frequency of CF is relatively rare in East Asia.
Amino Acid Substitution ; Base Sequence ; Cell Line ; Child, Preschool ; Cystic Fibrosis/diagnosis/*genetics ; Cystic Fibrosis Transmembrane Conductance Regulator/*genetics/metabolism ; Female ; Humans ; Lung/radiography ; *Mutation ; Patch-Clamp Techniques ; Republic of Korea ; Tomography, X-Ray Computed

Cystic fibrosis (CF) is inherited as an autosomal recessive trait, and the mutations in cystic fibrosis transmembrane conductance regulator (CFTR) gene contributes to the CF syndrome. Although CF is common in Caucasians, it is known to be rare in Asians. Recently, we experienced two cases of CF in Korean children. The patients were girls with chronic productive cough since early infancy. Chest computed tomography showed the diffuse bronchiectasis in both lungs, and their diagnosis was confirmed by the repeated analysis of a quantitative pilocarpine iontophoresis test (QPIT). The sweat chloride concentrations of the first patient were 108.1 mM/L and 96.7 mM/L. The genetic analysis revealed that she was the compound heterozygote of Q1291X and IVS8 T5 -M470V. In the second case, the sweat chloride concentrations were 95.0 mM/L and 77.5 mM/L. Although we performed a comprehensive search for the coding regions and exonintron splicing junctions of CFTR gene, no obvious disease-related mutations were detected in the second case. To our knowledge, this is the first report of CF in Korean children identified by a QPIT and genetic analysis. The possibility of CF should be suspected in those patients with chronic respiratory symptoms even in Korea.
Blood Pressure ; Bronchiectasis/diagnosis/pathology ; Child ; Cough ; Cystic Fibrosis/*diagnosis/*genetics ; Cystic Fibrosis Transmembrane Conductance Regulator/genetics ; DNA Mutational Analysis ; Exons ; Female ; Heterozygote ; Humans ; Introns ; Iontophoresis/*methods ; Korea ; Lung/pathology/radiography ; Muscarinic Agonists/*pharmacology ; Mutation ; Pancreas/pathology ; Pedigree ; Phenotype ; Pilocarpine/*pharmacology ; Polymorphism, Genetic ; Research Support, Non-U.S. Gov't ; Sinusitis/diagnosis/pathology ; Sweat ; Time Factors ; Tomography, X-Ray Computed

BACKGROUND: Cystic fibrosis is a chronic progressive autosomal recessive disorder caused by the CFTR gene mutations. It is quite common in Caucasians, but very rare in Asians. Sweat chloride test is known to be a screening test for the cystic fibrosis due to the fact that electrolyte levels in sweat are elevated in patients. In this study, sweat chloride levels in Korean population were measured and analyzed by using standardized pilocarpine iontophoresis sweat chloride test. METHODS: The sweat chloride test was performed in 47 patients referred to Yondong Severance Hospital from August, 2001 to April, 2007 and 41 healthy volunteers. The sweat chloride tests were conducted according to the CLSI C34-A2 guideline using pilocarpine iontophoresis method, and the chloride concentrations in sweat were measured by mercurimetric titration. RESULTS: Four patients showed sweat chloride concentrations higher than 60 mmol/L. Reference interval was calculated as 1.4-44.5 mmol/L by analysis of the results of healthy volunteers (n=41). Four patients who exhibited high sweat chloride levels, had characteristic clinical features of cystic fibrosis and their diagnoses were confirmed either by repeated sweat chloride test or genetic analysis. CONCLUSIONS: Standardized sweat chloride test can be utilized as a useful diagnostic tool for cystic fibrosis in Koreans. In cases of sweat chloride levels higher than 40 mmol/L, the test should be repeated for the possible diagnosis of cystic fibrosis. All the confirmed Korean cases of cystic fibrosis showed sweat chloride level above 60 mmol/L.
Adolescent ; Adult ; Child ; Child, Preschool ; Chlorides/*analysis/*standards ; Cystic Fibrosis/*diagnosis/genetics ; Female ; Humans ; Infant ; Iontophoresis/methods ; Korea ; Male ; Middle Aged ; Pilocarpine/chemistry ; Sequence Analysis, DNA ; Sweat/chemistry/*secretion