Clinical Phenotypes and Genotypic Spectrum of Cystic Fibrosis in Chinese Children

Increased prevalence of CFTR variants and susceptibility to CRS: A real-world study based on Chinese children

Background

Chronic Rhinosinusitis is a common disease in children. The main function of CFTR is to maintain the thickness of the mucous layer on the surface of the nasal mucosa. CFTR disease-causing variant can cause CFTR protein dysfunction and induce or aggravate chronic infection. However, the carrying status of the CFTR variants in the Chinese population is not clear.

Objective

To study the frequency and variants of CFTR in Chinese children with CRS and to analyze the CFTR variants and the clinical characteristics and susceptibility to CRS.

Methods

Whole Exome Sequencing was performed to analyze the CFTR genes in a total of 106 CRS children from the Chinese mainland area. The CFTR variants, frequency and clinical data were summarized and analyzed.

Results

A total of 31 CFTR variants were detected, of which the carrying rate of 7 sites was significantly higher than that of the population database. 88 patients carried more than 2 variants. 37 people carried variants (MAF < 0.05), of which 91.89% had a history of recurrent upper respiratory infections, 16 had nasal polyps, 5 had bronchiectasis, and 1 was diagnosed with CF-related disorders.

Conclusion

The carrying rate of CFTR variants in Chinese CRS children increased, and the highest rates of variants (MAF < 0.05) are p.I556V, p. E217G, c.1210-12[T]. Carrying multiple CFTR variants, especially p.E217G, p.I807 M, p.V920L and c.1210-12[T] may lead to increased susceptibility to CRS. There are CF-related disorders in patients with CRS.

Patients With Cystic Fibrosis Undergoing Total Hip and Total Knee Arthroplasty Are at Increased Risk for Perioperative Complications

INTRODUCTION

Patients with cystic fibrosis (CF) are living longer and may be considered for total hip arthroplasty (THA) or total knee arthroplasty (TKA). Perioperative outcomes and implant survival after these procedures performed for those with CF have not been previously described.

METHODS

Using the M151 PearlDiver database, a large, national, administrative database, THA and TKA patients with and without CF were identified and matched 1:10 based on age, sex, and Elixhauser Comorbidity Index. Ninety-day perioperative outcomes and 2-year revision rates were assessed and compared with multivariable logistic regression.

RESULTS

For THA, 185 patients with CF were matched with 1,846 control subjects without CF. Patients with CF were at significantly increased odds of 90-day postoperative events including sepsis (odd radio [OR] 4.15), pneumonia (OR 3.40), pleural effusion (OR 2.77), minor events (OR 1.73), any adverse event (OR 1.64), urinary tract infection (UTI) (OR 1.63), and severe events (OR 1.60) ( P < 0.05 for each). For TKA, 505 patients with CF were matched with 5,047 control subjects without CF. Patients with CF were at significantly increased odds of 90-day postoperative events including pneumonia (OR 4.95), respiratory failure (OR 4.31), cardiac event (OR 2.29), minor events (OR 2.16), pleural effusion (OR 2.35), severe events (OR 2.06), urinary tract infection (OR 2.06), any adverse event (OR 1.96), atelectasis (OR 1.94), and acute kidney injury (OR 1.61) ( P < 0.05 for each). For both THA and TKA, those with CF were not at greater odds of 2-year rates of revision.

DISCUSSION

After THA and TKA, those with CF were found to be at increased odds of multiple defined postoperative events (predominantly infectious/pulmonary), but not 2-year revision rates. These findings help define areas in need of focused optimization and are reassuring regarding risks of surgery.

Clinical and genetic characteristics of children with cystic fibrosis in Henan China: A single-center retrospective analysis

BACKGROUND

Despite the growing awareness of cystic fibrosis (CF) in China, few cases have been reported in Henan, which is the most populous province in the country. This study aimed to describe the clinical phenotype and genotype of children with CF in Henan.

METHODS

We retrospectively recruited 18 Chinese children with CF who presented to Children's Hospital affiliated to Zhengzhou University from January 2019 to June 2023. The demographic data, imaging examinations, and laboratory tests of the patients were reviewed to clarify the clinical phenotype. Whole exome sequencing was conducted to identify the genotype.

RESULTS

Respiratory diseases were the main clinical manifestation, including recurrent/persistent pneumonia (88.9%), sinusitis (77.8%), bronchiectasis (77.8%). CF-related liver disease and pancreatic insufficiency were less common. Infant cases had high frequency of pseudo-Bartter Syndrome (80.0%). Chest computed tomography showed bronchiectasis in older children and air trapping in infant cases. The most common pathogens in the airway were Pseudomonas aeruginosa (72.2%) and Staphylococcus aureus (66.7%). Twenty-five different cystic fibrosis transmembrane conductance regulator (CFTR) gene variants were detected, including five novel observations (c.1064C>G[p. Pro355Arg], c.1209+1G>C, c.1925C>G[p. Ser642X], c.2810T>G[p. Leu937Arg], and c.3792delA[p. Gly1265GlufsX13]). The most common variant was c.2909G>A(p. Gly970Asp), with a detected rate of 21.9%.

CONCLUSION

Children with CF in Henan had varied clinical phenotypes by age, with respiratory disease being predominant. The most frequent CFTR gene variant was c.2909G>A(p. Gly970Asp). This study is the first and most comprehensive one on the clinical phenotype and genotype of children with CF in Henan, China. We also reported the first CF case of Mycobacterium abscessus infection in China.

Morbidity and treatment costs of cystic fibrosis in a middle-income country

Introduction

: Asian children with cystic fibrosis (CF) managed in Malaysia have significant morbidity with limited access to life-sustaining treatments. We determined the morbidity and treatment cost of CF in a resource-limited country.

Methods

This cross-sectional study included all children diagnosed with CF in our centre. Data on clinical presentation, genetic mutation, serial spirometry results and complications were collected. Out-of-pocket (OOP) and healthcare costs over 1 year were retrieved for patients who were alive. Cohen's d and odds ratio (OR) were used to determine the effect size.

Results

Twenty-four patients were diagnosed with CF. Five patients died at a median (range) age of 18 (0.3-22) years. F508deletion (c. 1521_1523delCTT) was found in 20% of the alleles, while 89% of the variants were detected in nine patients. Body mass index (BMI) Z score was >-1.96 in 70.6% of patients. Two thirds (68%) were colonised with Pseudomonas aeruginosa, and this was associated with lower weight (P = 0.009) and BMI (P = 0.02) Z scores. Only 18% had FEV1 Z scores >-1.96. Early symptom onset (d = 0.74), delayed diagnosis (d = 2.07), a low FEF25-75 Z score (d = 0.82) and a high sweat conductance (d = 1.19) were associated with death. Inpatient cost was mainly from diagnostic tests, while medications contributed to half of the outpatient cost.

Healthcare utilisation cost was catastrophic, amounting to 20% of the total income.

Conclusion

Asian children with CF suffer significant complications such as low weight, low lung function and shortened lifespan. P. aeruginosa colonisation was frequent and associated with poor growth. Healthcare cost to parents was catastrophic.

Case report of a pediatric Chinese cystic fibrosis patient with the c.1521_1523delCTT/c.3874-4522A>G genotype

This report describes a case of an 11-year-old Chinese boy with cystic fibrosis (CF) bearing the c.1521_1523delCTT/c.3874-4522A>G genotype, an extremely rare CF genotype in the Chinese population. Notably, the deep intron mutation c.3874-4522A>G, which has mainly been reported in patients with phenotypically mild CF, is identified here for the first time in a Chinese patient with severe CF. In the case discussed here, the c.3874-4522A>G mutation was associated with severe pulmonary disease with early symptoms onset, progressive bronchiectasis, recurrent airway infection with both Pseudomonas aeruginosa and methicillin-resistant Staphylococcus aureus, rapid decline of lung function and poor weight gain. Despite intensive hospital-based pulmonary care and optimized therapy, the child died of cardiopulmonary failure 3 months after discharge.

Genetic spectrum of Chinese children with cystic fibrosis: comprehensive data analysis from the main referral centre in China

BACKGROUND AND OBJECTIVES

Cystic fibrosis (CF) is a heterogeneous disease with a diverse genetic spectrum among populations. Few patients with CF of Chinese origin have been reported worldwide. The objective of this study is to characterise the genotypic features of CF in Chinese children.

METHODS

We recruited and characterised the genetic manifestations of 103 Chinese children with CF in Beijing Children's Hospital from 2010 to 2022. Whole-exome sequencing were performed to define the genotypes. Meanwhile, other 99 genetically confirmed patients with Chinese origin described in 45 references were also summarised.

RESULTS

158 different variants including 23 novel observations were identified after sequencing. The majority of CFTR variants (82.3%) in Chinese have been observed only once or twice. 43.7% of the variants were only identified in patients of Chinese origin. The c.2909G>A(p.Gly970Asp), c.1766+5G>T and c.1657C>T(p.Arg553X) were the most frequent variants among Chinese patients, with allele frequency of 12.1%, 5.4% and 3.6%, respectively. The first two variants both showed significant Chinese ethnic tendency, while the latter one most likely came from Europeans for historical reasons. They also demonstrated significant differences in geographical distribution. c.1521_1523delCTT(p.F508del) was rarely observed in patients of pure Chinese origin, with an allele frequency of 1.8%. Two de novo variants (c.960dupA[p.Ser321IlefsX43] and c.2491-2A>G) and two deep-intronic variants (c.3718-2477C>T and c.3874-4522A>G) were identified, which were also quite rare among Chinese.

CONCLUSIONS

The genetic spectrum of CF in Chinese is unique and quite different from that observed in Caucasians. The geographical distributions of the most frequent variants were reported for the first time.

Systematic estimation of cystic fibrosis prevalence in Chinese and genetic spectrum comparison to Caucasians

Background

Cystic fibrosis (CF) is a common, life-threatening genetic disease in Caucasians but rarely reported in Chinese population. The prevalence and population-specific genetic spectrum of CF in China needs to be systematically estimated and compared with Caucasians.

Materials and methods

We reviewed 30,951 exome-sequencing samples, including 20,909 pediatric patient samples and 10,042 parent samples, from Chinese Children's Rare Disease Genetic Testing Clinical Collaboration System (CCGT). After the in-lab filtration process, 477 candidate variants of CFTR gene were left and 53 variants were manually curated as pathogenic/likely-pathogenic (P/LP). These P/LP variants were adopted to estimate CF prevalence in three methods: the carrier frequency method, the permutation-combinations method and the Bayesian framework method. Allele frequencies of the 477 CFTR variants were compared with non-Finland European (NFE) and East Asian (EAS) from gnomAD database. To investigate the haplotype structure difference of CFTR, another 2067 whole-genome-sequencing samples from CCGT and 195 NFE from 1000 genome project were analyzed by Shapeit4 software.

Result

With the 53 manually curated P/LP variants in CFTR gene, we excluded individuals identified or suspected with CF and their parents in our cohorts and estimated the Chinese CF prevalence is approximately 1/128,434. Only 21 (39.6%) of the 53 variants were included in Caucasian specific CF screening panels, resulting in significantly under-estimation of CF prevalence in our children cohort (1/143,171 vs. 1/1,387,395, P = 5e−24) and parent’s cohort (1/110,127 vs. 1/872,437, P = 7e−10). The allele frequencies of six pathogenic variants (G970D, D979A, M469V, G622D, L88X, 1898+5G->T) were significantly higher in our cohorts compared with gnomAD-NFE population (all P-value < 0.1). Haplotype analysis showed more haplotype diversity in Chinese compared to Caucasians. In addition, G970D and F508del were founder mutation of Chinese and Caucasians with two SNPs (rs213950-rs1042077) identified as related genotype in exon region.

Conclusions

Chinese population showed significantly different genetic spectrum pattern in CFTR gene compared with Caucasian population, and thus a Chinese-specific CF screening panel is needed.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13023-022-02279-9.

Analysis of Clinical Manifestations, Imaging Features, and Gene Mutation Characteristics of 6 Children with Cystic Fibrosis in China

Objective

To explore the clinical manifestations, imaging features, and gene mutation characteristics of 6 children with cystic fibrosis (CF) so as to improve the understanding and diagnosis awareness of CF in children and reduce the missed diagnosis and misdiagnosis.

Methods

The clinical manifestations, imaging, and gene mutation data of six children with CF were collected and retrospectively analyzed.

Results

Among the 6 cases of CF, there were 4 males and 2 females. Among the 6 children with CF, 5 cases presented with recurrent respiratory tract infection. Etiology suggested 3 cases of Pseudomonas aeruginosa and 2 cases of Staphylococcus aureus. 3 cases had pancreatic exocrine dysfunction, manifested as diarrhea and aliphatic diarrhea, of which 1 case had high lipase in blood examination, and pancreatic ultrasound showed rough and enhanced pancreatic echo, considering pancreatic cystic fibrosis. 2 cases of CF combined with pseudo-Bartter syndrome (PBS); 1 case involved only the biliary tract and started with cholestasis without other systemic involvement. In 2 cases of sweat test, sweat chloride ions were all >60 mmol/L. 3 cases underwent fiberoptic bronchoscopy, and a large number of sticky secretions were visible under the bronchoscopy. CT of the chest revealed thickening of the bronchial wall (3 cases), bronchiectasis (1 case), atelectasis (1 case), and thin bronchial lumen (2 cases). 1 patient was found to have small airway lesions and mosaic perfusion during follow-up. All 6 children with CF underwent genetic testing. A total of 12 CF transmembrane conductance regulator (CFTR) gene mutations were found, of which 4 mutations were not reported in the literature.

Conclusion

CF is a disease caused by CFTR mutation. The incidence of this disease in China is low, and the clinical manifestations have great differences. The main symptoms are respiratory symptoms. Some children have gastrointestinal symptoms and/or PBS, and some children only show a single systemic lesion.

A review of cystic fibrosis: Basic and clinical aspects

Cystic fibrosis is an autosomal recessive disease caused by mutations of the gene encoding the cystic fibrosis transmembrane conductance regulator (CFTR). Here we summarize, at the basic descriptive level, clinical and genetic characteristics of cystic fibrosis gene mutations, while emphasizing differences between CF mutations found in Chinese pediatric CF patients compared to those found in Caucasian CF patients. In addition, we describe animal models used to study human cystic fibrosis disease and highlight unique features of each model that mimic specific human CF-associated signs and symptoms. At the clinical level, we summarize CF clinical manifestations and diagnostic, treatment, and prognostic methods to provide clinicians with information toward reducing CF misdiagnosis and missed diagnosis rates.

Prognosis and treatment of 46 Chinese pediatric cystic fibrosis patients

BACKGROUND

Since public awareness of cystic fibrosis (CF) has increased, more children have been diagnosed with CF in China. This study aimed to investigate medical and other challenges faced by pediatric CF patients in China.

METHOD

Treatments and treatment outcomes were retrospectively analyzed for 46 pediatric CF patients diagnosed from August 2009 to June 2019. Pre- and post-treatment results were compared using independent samples t-test.

RESULTS

Of 46 pediatric CF study patients, four died and five were lost to follow-up. Thirty-seven patients were monitored for 0.03 to 9.21 years; patients exhibited fewer attacks of respiratory tract infections after diagnosis (4.49 ± 2.13 episodes/year before diagnosis vs 1.97 ± 1.87 times/year after 1-year treatment, p < 0.05), significantly reduced sputum production and experienced 1.62 ± 1.71 exacerbations/year. Patient mean body mass index was 16.87 ± 3.53 and pancreatic malfunction persisted in 15 patients. For 17 children, no significant differences in lung function were found at follow-up as compared to lung function at diagnosis (FEV₁: 82.45% ± 16.56% vs 75.26% ± 22.34%, FVC: 87.18% ± 13.64% vs 86.99% ± 19.95%, FEF_75%: 46.51% ± 28.78% vs 36.63% ± 24.30%, P = 0.27, 0.97, 0.20, respectively). Pseudomonas aeruginosa (17/27) and bronchiectasis (22/22) were found during follow-up evaluation. Twenty-four patients (64.8%) maintained good adherence to therapies. Overall, azithromycin and tobramycin treatments were administered for 0.5-62 months and 0.5-48 months, respectively, and triggered no obvious adverse reactions.

CONCLUSION

No obvious declines in clinical presentation or lung function were found in Chinese pediatric CF patients after receiving standard therapeutic and active treatments, although malnutrition and low compliance were persistent challenges.

Emerging Fungal Threats in Cystic Fibrosis

In the past three decades, fungal respiratory colonization and fungal respiratory infections increasingly raised concern in cystic fibrosis (CF). Reasons for this are a better knowledge of the pathogenicity of fungi, whereby detection is sought in more and more CF centers, but also improvement of detection methods. However, differences in fungal detection rates within and between geographical regions exist and indicate the need for standardization of mycological examination of respiratory secretions. The still existing lack of standardization also complicates the assessment of fungal pathogenicity, relevance of fungal detection and risk factors for fungal infections. Nevertheless, numerous studies have now been conducted on differences in detection methods, epidemiology, risk factors, pathogenicity and therapy of fungal diseases in CF. Meanwhile, some research groups now have classified fungal disease entities in CF and developed diagnostic criteria as well as therapeutic guidelines.The following review presents an overview on fungal species relevant in CF. Cultural detection methods with their respective success rates as well as susceptibility testing will be presented, and the problem of increasing azole resistance in Aspergillus fumigatus will be highlighted. Next, current data and conflicting evidence on the epidemiology and risk factors for fungal diseases in patients with CF will be discussed. Finally, an overview of fungal disease entities in CF with their current definitions, diagnostic criteria and therapeutic options will be presented.

Whole-Exome Sequencing Identified CFTR Variants in Two Consanguineous Families in China

Background

Cystic fibrosis (CF) is an autosomal recessive disease caused by genetic variants of the cystic fibrosis transmembrane conductance regulator (CFTR) gene. It is a common hereditary disease in Caucasians while rare in the Chinese. Until now, only 87 Chinese patients have been reported with molecular confirmations. The variant spectrum and clinical features of Chinese CF patients are obviously different from those of Caucasians.

Materials and Methods

Whole-exome sequencing was applied to analyze the exome of three individuals who have only the typical CF phenotype in the respiratory system from two consanguineous families. The protein domain and structure analysis were applied to predict the impact of the variants. Sanger sequencing was applied to validate the candidate variants.

Results

A previously reported homozygous variant in CFTR (NM_000492.4: c.1000C > T, p.R334W) was identified in proband I. A novel homozygous variant in a polymorphic position (NM_000492.4: c.1409T > A, p.V470E) was identified in two individuals in the family II. The novel CFTR variant predicted to be disease-causing is the first, to the best of our knowledge, to be reported in CFTR. However, in vitro validation is still needed.

Conclusion

Our finding expands the variant spectrum of CFTR, reveals clearer clinical phenotype distinction and variant spectrum distinction between Chinese and Caucasian CF patients, and contributes to a more rapid genetic diagnosis and future genetic counseling.

Pseudo-Bartter syndrome in Chinese children with cystic fibrosis: Clinical features and genotypic findings

OBJECTIVES

To characterize the clinical and genotypic features of cystic fibrosis-associated pseudo-Bartter syndrome (CF-PBS) in Chinese children.

METHODS

We recruited and characterized the clinical manifestations of 12 Chinese children with CF-PBS. Sweat test, blood and urinary analysis, sputum culture, chest and sinus computed tomography, and abdominal ultrasonography were obtained. Whole-exome sequencing, bioinformatics analysis, and Sanger sequencing validation were performed to define the genotypes.

RESULTS

CF-PBS was accompanied by recurrent and/or persistent pneumonia (91.7%), pancreatitis (83.3%), vomiting and/or diarrhea (66.7%), failure to thrive and liver disease (58.3% respectively), among our patients. The predominant organisms found in the airways were Pseudomonas aeruginosa (83.3%) and Staphylococcus aureus (75.0%). The mean concentrations of blood gas and electrolytes were pH 7.58, bicarbonate 40.8 mmol/L, sodium 125.9 mmol/L, chloride 77.5 mmol/L, and potassium 2.6 mmol/L. A high recurrence rate (50.0%) of CF-PBS was observed despite continued electrolyte supplementation during follow-up. In all, 19 different variants of CFTR gene were identified, and 10 of these were found to be novel observations (c.262_266delTTATA[p.L88FfsX21], c.579+2insACAT, c.1210-3C>G, c.1733T>C[p.L578P], c.2236_2246delGAGGCGATACTinsAAAAATC[p.E746KfsX8], c.3068T>G [p.I1023R], c.3635delT[p.V1212AfsX16], c.3859delG[p.G1287EfsX2], c.3964-7A>G and ΔE23 [c.3718-?_3873+?del]). The c.2909G>A[p.G970D] was the most common variant, with an allele frequency of 16.6%. A homozygous genotype of c.1521_1523delCTT[p.F508del] was discovered for the first time in patients of Chinese origin.

CONCLUSIONS

In China, CF-PBS usually presents early and recurs frequently in infancy, accompanied by multiple comorbidities. Recurrence of CF-PBS in school-going patients does occur but is rare. The p.G970D is the most frequent variant, with a significant ethnic tendency of Chinese origin.

A systematic review of the clinical and genetic characteristics of Chinese patients with cystic fibrosis

OBJECTIVES

To investigate and summarize the clinical and genetic characteristics of Chinese cystic fibrosis (CF) patients to improve clinicians' understanding and decrease the rates of misdiagnosis and missed diagnoses in China.

METHODS

The EMBASE, Cochrane Library, PubMed and SinoMed databases were searched for studies involving Chinese CF patients from January 1975 to August 2019.

RESULTS

In total, 113 Chinese patients, including 53 males and 60 females, were reported. Nineteen patients had a family history of CF. The median age at diagnosis was 8.7 years. Among Chinese CF patients, 70.8% had bronchiectasis, 9.7% had a hemoptysis history, 33.6% had clubbed fingers, 17.7% had allergic bronchopulmonary aspergillosis, and 29.2% had chronic diarrhea; the incidence of malnutrition was 52.2%. Five patients had jaundice, 26 patients had hepatomegaly, and 9 patients had meconium ileus in the neonatal period, and the incidence of liver cirrhosis was 5.3%. The predominant organism in airways was Pseudomonas aeruginosa, followed by Staphylococcus aureus. Seventy-nine patients underwent the sweat test, and all of them were positive, with an average chloride ion level of 122.2 mmol/L. Eighty-eight Chinese CF patients underwent genetic testing, and 74 CF transmembrane conductance regulator (CFTR) gene mutations were reported. The most common gene mutation was c.2909G→A. One Phe508del gene mutation was observed.

CONCLUSION

The common clinical manifestations and CFTR gene mutations in Chinese CF patients are different from those in Caucasian patients. The age at CF diagnosis in China is relatively old, suggesting that the CF incidence in China may be seriously underestimated.

CFTR deficiency causes cardiac dysplasia during zebrafish embryogenesis and is associated with dilated cardiomyopathy

Mutations in the CFTR gene cause cystic fibrosis (CF) with myocardial dysfunction. However, it remains unknown whether CF-related heart disease is a secondary effect of pulmonary disease, or an intrinsic primary defect in the heart. Here, we used zebrafish, which lack lung tissue, to investigate the role of CFTR in cardiogenesis. Our findings demonstrated that the loss of CFTR impairs cardiac development from the cardiac progenitor stage, resulting in cardiac looping defects, a dilated atrium, pericardial edema, and a decrease in heart rate. Furthermore, we found that cardiac development was perturbed in wild-type embryos treated with a gating-specific CFTR channel inhibitor, CFTRinh-172, at the blastula stage of development, but not at later stages. Gene expression analysis of blastulas indicated that transcript levels, including mRNAs associated with cardiovascular diseases, were significantly altered in embryos derived from cftr mutants relative to controls. To evaluate the role of CFTR in human heart failure, we performed a genetic association study on individuals with dilated cardiomyopathy and found that the I556V mutation in CFTR, which causes a channel defect, was associated with the disease. Similar to other well-studied channel-defective CFTR mutants, CFTR I556V mRNA failed to restore cardiac dysplasia in mutant embryos. The present study revealed an important role for the CFTR ion channel in regulating cardiac development during early embryogenesis, supporting the hypothesis that CF-related heart disease results from an intrinsic primary defect in the heart.

Characterization of clinical and genetic spectrum of Chinese patients with cystic fibrosis

Background

Cystic fibrosis (CF) is a rare autosomal recessive disorder caused by biallelic mutations in the cystic fibrosis transmembrane conductance regulator (CFTR) gene. The clinical features and mutation spectrum of CF have been well characterized in Caucasians, while limited studies were conducted in Chinese patients.

Subjects and methods

A total of 20 individuals from 19 families were diagnosed with CF in this study. We analyzed the clinical features and screened all coding exons of CFTR using a combination of Sanger sequencing and multiplex ligation-dependent probe amplification analysis.

Results

The median age at onset was 9.3 years in our cohort, while the median age at diagnosis was 19 years. The respiratory system was most frequently affected in this study: all patients (100%, 19/19) presented diffuse bronchiectasis and 61.1% (11/18) of patients showed a forced expiratory volume in 1 s below 80% predicted. Six patients (6/20, 30%) exhibited allergic bronchopulmonary aspergillosis (ABPA). Only 4 (4/20, 20%) patients presented pancreatic exocrine insufficiency (PI). Three adult male patients receiving examinations for congenital bilateral absence of the vas deferens were all found positive for the condition. A total of 22 distinct mutations were detected in this cohort, with the variant p.G970D as the most common variant (12/38 alleles, 31.6%). Four variants (p.Y109D, p.I203F, p.D572E, and exon 2–3 deletion) were novel, which expanded the mutation spectrum of Chinese CF patients.

Conclusions

Chinese CF patients showed different clinical features and a distinct CFTR mutation spectrum compared with Caucasians. There is a significant diagnosis delay, suggesting the current underdiagnosis of CF in China.

Pneumonia due to Pandoraea Apista after evacuation of traumatic intracranial hematomas:a case report and literature review

Background

Pandoraea species is a newly described genus, which is multidrug resistant and difficult to identify. Clinical isolates are mostly cultured from cystic fibrosis (CF) patients. CF is a rare disease in China, which makes Pandoraea a total stranger to Chinese physicians. Pandoraea genus is reported as an emerging pathogen in CF patients in most cases. However, there are few pieces of evidence that confirm Pandoraea can be more virulent in non-CF patients. The pathogenicity of Pandoraea genus is poorly understood, as well as its treatment. The incidence of Pandoraea induced infection in non-CF patients may be underestimated and it’s important to identify and understand these organisms.

Case presentation

We report a 44-years-old man who suffered from pneumonia and died eventually. Before his condition deteriorated, a Gram-negative bacilli was cultured from his sputum and identified as Pandoraea Apista by matrix-assisted laser desorption ionization–time-of-flight mass spectrometry (MALDI-TOF MS).

Conclusion

Pandoraea spp. is an emerging opportunistic pathogen. The incidences of Pandoraea related infection in non-CF patients may be underestimated due to the difficulty of identification. All strains of Pandoraea show multi-drug resistance and highly variable susceptibility. To better treatment, species-level identification and antibiotic susceptibility test are necessary.

c.753_754delAG, a novel CFTR mutation found in a Chinese patient with cystic fibrosis: A case report and review of the literature

BACKGROUND

Cystic fibrosis (CF) is rare in Asian populations relative to the Caucasian population. In this paper, we report the cystic fibrosis transmembrane conductance regulator (CFTR) variation in a family of Chinese CF patients, and systematically review the previous literature.

CASE SUMMARY

Here we report a 30-month-old Chinese girl who was diagnosed with CF based on her history and symptoms such as recurrent productive cough, wheezing with repeated infection of Pseudomonas aeruginosa, and parasinusitis. Chest computed tomography (CT) scanning revealed obvious exudative lesions and bilateral bronchiectasis. Liver CT scanning revealed a low-density lesion in the left lobe of the liver. A diagnosis of CF was made based upon CFTR gene tests. The CFTR gene was sequenced using the blood samples of her and her parents and showed a heterozygous novel missense mutation of c.753_754delAG in exon 7. In addition, a heterozygous c.1240 C>T mutation was found in exon 10 of the CFTR. The mutation c.753_754delAG was verified to have been inherited from her mother, and the c.1240 C>T mutation was from her father who was diagnosed with congenital absence of vas deferens.

CONCLUSION

A novel mutation of CFTR, c.753_754delAG, was found in a Chinese CF child. c.2909G>A is the most common mutation among Chinese CF patients.

Liver Failure in a Chinese Cystic Fibrosis Child With Homozygous R553X Mutation

Cystic fibrosis (CF) is a relatively rare disease in Asians with various clinical characteristics, including CF-associated liver disease (CFLD), which is a common early non-pulmonary complication. This case report describes a Chinese CF patient harboring a homozygous nonsense mutation (c.1657C>T, p.R553X) who was failure to thrive and had intermittently diarrhea during the first year after birth. Liver function test of the patient showed the mildly and intermittently elevated alanine aminotransferase (ALT) levels ranging from 70 to 92 U/L and aspartate aminotransferase (AST) levels ranging from 80 to 90 U/L, which began at 8 months of age and lasted for 4 years without CF diagnosis. In addition, abdominal computed tomography (CT) revealed diffuse fatty infiltration of the liver at 4 years old and gradually developed hepatic cirrhosis. Subsequently, cirrhosis rapidly progressed with obvious splenomegaly and pancreatic insufficiency and the patient died of liver failure with coagulopathy by the age of 6 years old. Pediatricians should remain vigilant to avoid failure to diagnose CF, the occurrence of which may be underestimated, and pay greater attention to the patients with atypical clinical manifestations in Asian countries.

Clinical and genetic characteristics of cystic fibrosis in CHINESE patients: a systemic review of reported cases

Cystic fibrosis (CF) is a rare disease most commonly seen in Caucasians. Only a few Chinese CF patients have been described in literature, taking into account the large population of China. In this systematic review, we collected the clinical and genetic information of 71 Chinese CF patients based on all available data. Compared with Caucasians, Chinese CF patients often present atypical symptoms, mainly displaying symptoms of pulmonary infection with fewer digestive symptoms. An ethnicity-specific CFTR variant spectrum was also observed in CF patients of Chinese origin, with p.Gly970Asp as the most common mutation while p.Phe508del, the most common pathogenic mutation in CF patients of Caucasian origin, is rare, suggesting the necessity of a Chinese-specific CFTR variant screening panel. Besides, multiplex ligation-dependent probe amplification analysis should be routinely considered, especially for those with unidentified mutations. Potential under-diagnosis of CF in Chinese patients might be caused by a combination of atypical clinical features and genetic heterogeneity in Chinese CF patients, the inaccessibility of sweat and genetic testing facilities, and the one-child policy in China. With the approval of promising small molecule correctors and potentiators, molecular characterization of Chinese-specific CFTR mutations will help to realize more precise treatment for Chinese CF patients.

The co-colonization prevalence of Pseudomonas aeruginosa and Aspergillus fumigatus in cystic fibrosis: A systematic review and meta-analysis

PURPOSE

The co-colonization prevalence of P. aeruginosa and A. fumigatus in cystic fibrosis (CF) has been inconsistently reported. The purpose of this systematic review and meta-analysis was to estimate the overall co-colonization prevalence of P. aeruginosa and A. fumigatus in CF.

METHODS

The Embase, PubMed and Web of Science databases were systematically searched for studies reporting the co-colonization prevalence of P. aeruginosa and A. fumigatus in CF. The co-colonization prevalence of two pathogenic microorganisms in the individual studies was assessed by calculating the proportion and 95% confidence interval (CI). The random effects model was used to calculate the pooled prevalence. The I² test was used to assess statistical heterogeneity. The funnel plot and two statistical methods were used to assess publication bias.

RESULTS

Twenty-three eligible studies were included in this analysis. The pooled co-colonization prevalence of P. aeruginosa and A. fumigatus in CF patients was 15.8% (95% CI: 9.9-21.8). The co-colonization prevalence of P. aeruginosa and A. fumigatus chronic colonization was lower than that of intermittent colonization, higher in sputum cultures than in bronchoalveolar lavage (BAL) cultures, and lower in children than in adults. There was a statistically significant difference in co-colonization prevalence among studies from different decades, but the prevalence was similar in different geographical regions and with different study types.

CONCLUSIONS

The co-colonization prevalence of P. aeruginosa and A. fumigatus in the lower respiratory tract of CF patients was high. The anti-infective treatment in exacerbation of CF should be considered to cover the two pathogenic microorganisms simultaneously. Large-scale research is still needed to obtain more accurate co-colonization data.

Clinical characterization and diagnosis of cystic fibrosis through exome sequencing in Chinese infants with Bartter-syndrome-like hypokalemia alkalosis

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.

A novel homozygous complex deletion in CFTR caused cystic fibrosis in a Chinese patient

Cystic fibrosis (CF) is the most frequent lethal genetic disorder among Caucasians, but is considered to be a very rare disease in Chinese population. Here, we present an 11-year-old Chinese CF patient with disseminated bronchiectasis and salty sweat, for whom exon sequencing followed by multiplex ligation-dependent probe amplification analysis of the CFTR gene was applied for mutation screening. A homozygous deletion involving exon 20 of CFTR was observed in the patient's genome. Molecular characterization of the breakpoints indicated that both alleles of this locus had an identical novel complex rearrangement (c.3140-454_c.3367+249del931ins13, p.R1048_G1123del), leading to an in-frame removal of 76 amino acid residues in the second transmembrane domains of the CFTR protein. Although a same haplotype containing this complex rearrangement was observed on both of the maternal and paternal alleles, the parents denied any blood relationship as far as they know. Genome-wide homozygosity mapping was performed through SNP microarray and only a single homozygous interval of ~14.1 Mb at chromosome 7 containing the CFTR gene was observed, indicating the possible origin of the deletion from a common ancestor many generations ago. This study expands the mutation spectrum of CFTR in patients of Chinese origin and further emphasizes the necessity of MLPA analysis in mutation screening for CF patients.

Ethnicity impacts the cystic fibrosis diagnosis: A note of caution

BACKGROUND

The diagnosis of Cystic Fibrosis (CF) is by consensus based on the same parameters in all patients, yet the influence of ethnicity has only scarcely been studied. We aimed at elucidating the impact of Asian descent on the diagnosis of CF.

METHODS

We performed a retrospective analysis of the CFTR2 and UK CF databases for clinical phenotype, sweat chloride values and CFTR mutations and compared the diagnostic characteristics of Asian to non-Asian patients with CF.

RESULTS

Asian patients with CF do not have a worse clinical phenotype. The repeatedly reported lower FEV₁ of Asian patients with CF is attributable to the influence of ethnicity on lung function in general. However, pancreatic sufficiency is more common in Asian patients with CF. The diagnosis of CF in people with Asian ancestry is heterogeneous as mean sweat chloride values are lower (92±26 versus 99±22mmol/L in controls) and 14% have sweat chloride values below 60mmol/L (versus 6% in non-Asians). Also, CFTR mutations differ from those in Caucasians: 55% of British Asian patients with CF do not have one mutation included in the routine newborn screening panel.

CONCLUSIONS

Bringing together the largest cohort of patients with CF and Asian ethnicity, we demonstrate that Asian roots impact on all three CF diagnostic pillars. These findings have implications for clinical practice in the increasingly ethnically diverse Western population.

F508del genotype in endoscopic sinus surgery: do differences in outcomes exist between genotypic subgroups?

BACKGROUND

The impact of endoscopic sinus surgery (ESS) on pulmonary function in cystic fibrosis (CF) patients with chronic rhinosinusitis remains unclear, as studies have demonstrated conflicting results. To date, no study has looked specifically at the impact of CF genotype on lung function after ESS. In this study, we reviewed changes in pulmonary function test (PFT) results after ESS in F508del homozygotes and heterozygotes.

METHODS

The charts of 25 patients with CF without prior lung transplant, who underwent ESS performed by the same surgeon between the period of July 2005 to July 2015, were retrospectively reviewed. Data including genotype and PFT results were collected. Patients were grouped based on genotype. Pre- and postoperative PFTs were compared.

RESULTS

Some differences in PFT outcomes after ESS could be seen on subgroup analyses. For example, when considered as a whole group, the overall cohort showed a significant improvement from preoperative FEV₁ levels at 6 months after surgery (p = 0.0127). Interestingly, on subgroup analysis, the heterozygous group saw significant improvements from preoperative FEV₁ levels at 6 and 12 months (p = 0.0155 and p = 0.0333, respectively). No significant improvements were seen from "baseline" FEV₁ in either group at any timepoint.

CONCLUSION

Prior studies investigating the impact of ESS on pulmonary function in CF patients have shown conflicting results. To our knowledge, those earlier udies did not separate and compare different genotypes, which may have introduced heterogeneity in their patient populations. Our study suggests that grouping CF patients more strictly according to genotype or disease severity when investigating outcomes may reveal differences among various subgroups.