Incidence of SARS-CoV-2 in people with cystic fibrosis in Europe between February and June 2020.

BACKGROUND: Viral infections can cause significant morbidity in cystic fibrosis (CF). The current Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) pandemic could therefore have a serious impact on the health of people with CF (pwCF). METHODS: We used the 38-country European Cystic Fibrosis Society Patient Registry (ECFSPR) to collect case data about pwCF and SARS-CoV-2 infection. RESULTS: Up to 30 June 2020, 16 countries reported 130 SARS-CoV-2 cases in people with CF, yielding an incidence of 2.70/1000 pwCF. Incidence was higher in lung-transplanted patients (n=23) versus non-transplanted patients (n=107) (8.43 versus 2.36 cases/1000). Incidence was higher in pwCF versus the age-matched general population in the age groups <15, 15-24, and 25-49 years (p<0.001), with similar trends for pwCF with and without lung transplant. Compared to the general population, pwCF (regardless of transplantation status) had significantly higher rates of admission to hospital for all age groups with available data, and higher rates of intensive care, although not statistically significant. Most pwCF recovered (96.2%), however 5 died, of whom 3 were lung transplant recipients. The case fatality rate for pwCF (3.85%, 95% CI: 1.26-8.75) was non-significantly lower than that of the general population (7.46%; p=0.133). CONCLUSIONS: SARS-CoV-2 infection can result in severe illness and death for pwCF, even for younger patients and especially for lung transplant recipients. PwCF should continue to shield from infection and should be prioritized for vaccination.

Factors for severe outcomes following SARS-CoV-2 infection in people with cystic fibrosis in Europe.

BACKGROUND: Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection in people with cystic fibrosis (pwCF) can lead to severe outcomes. METHODS: In this observational study, the European Cystic Fibrosis Society Patient Registry collected data on pwCF and SARS-CoV-2 infection to estimate incidence, describe clinical presentation and investigate factors associated with severe outcomes using multivariable analysis. RESULTS: Up to December 31, 2020, 26 countries reported information on 828 pwCF and SARS-CoV-2 infection. Incidence was 17.2 per 1000 pwCF (95% CI: 16.0-18.4). Median age was 24 years, 48.4% were male and 9.4% had lung transplants. SARS-CoV-2 incidence was higher in lung-transplanted (28.6; 95% CI: 22.7-35.5) versus non-lung-transplanted pwCF (16.6; 95% CI: 15.4-17.8) (p≤0.001).SARS-CoV-2 infection caused symptomatic illness in 75.7%. Factors associated with symptomatic SARS-CoV-2 infection were age >40 years, at least one F508del mutation and pancreatic insufficiency.Overall, 23.7% of pwCF were admitted to hospital, 2.5% of those to intensive care, and regretfully 11 (1.4%) died. Hospitalisation, oxygen therapy, intensive care, respiratory support and death were 2- to 6-fold more frequent in lung-transplanted versus non-lung-transplanted pwCF.Factors associated with hospitalisation and oxygen therapy were lung transplantation, cystic fibrosis-related diabetes (CFRD), moderate or severe lung disease and azithromycin use (often considered a surrogate marker for Pseudomonas aeruginosa infection and poorer lung function). CONCLUSION: SARS-CoV-2 infection yielded high morbidity and hospitalisation in pwCF. PwCF with forced expiratory volume in 1 s <70% predicted, CFRD and those with lung transplants are at particular risk of more severe outcomes.

Comprehensive genetic study of cystic fibrosis in Slovak patients in 25 years of genetic diagnostics.

INTRODUCTION: Cystic fibrosis (CF) has one of the longest histories in hereditary disease molecular diagnostics. However, identification of causative mutations in the CFTR gene is complicated by over 2000 currently identified mutations; with more still being discovered. Knowledge of mutation spectrum may improve effective routine diagnostics and is obligatory in mutation-specific treatment. OBJECTIVES: This study presents comprehensive mutation screening of the CFTR gene; with 275 unrelated, clinically confirmed and treated cystic fibrosis (CF) patients diagnosed in 25 years genetic testing in Slovakia. METHODS: Detection of the most common CFTR mutations was performed by ELUCIGENE 29 and ELUCIGENE CF EU2 kits. HRM and dHPLC mutation screening methods with subsequent Sanger sequencing were applied for minor mutation screening, and MLPA analysis for deletion/duplication detection. RESULTS: A total of 70 different mutations were identified, from which the most common mutation F508del accounted for 60.36% of all disease alleles and 8 mutations have currently been observed only in Slovak patients. Two large deletions identified on chromosomes 2 and 22 were further characterized to identify breakpoints. Based on mutation screening results and neonatal screening we estimated incidence in Slovakian newborns at approximately 1:6000-7000. CONCLUSION: In our study, we identified mutations in 98.54% of all disease chromosomes, while 86.54% were identified using ELUCIGENE kits, 0.54% by MLPA analysis and 11.46% by sequencing analysis. Knowledge of the mutation spectrum in genetically diagnosed patients improves possibilities of genetic counseling and cascade screening in the affected families and Slovak population.

Study of the effect of DNA polymorphisms in the mannose-binding lectin gene (MBL2) on disease severity in Slovak cystic fibrosis patients.

Lung infections are the leading cause of morbidity and mortality in cystic fibrosis (CF). Mannose-binding lectin (MBL) is a key factor in innate immunity. We therefore investigated whether MBL2 gene variants are associated with pulmonary function or susceptibility to Pseudomonas aeruginosa and Burkholderia cepacia infection in Slovak patients affected with CF. DNA polymorphisms in exon 1 and the promoter region were typed by single base primer extension assay in 91 patients and 100 healthy controls. The concentrations of MBL protein were determined in 34 patients by a sandwich enzyme-linked immunosorbent assay, and spirometric and microbiological data were collected from medical records. In this study we found that MBL2 genotypes were associated neither with earlier acquisition of P. aeruginosa or B. cepacia nor with reduced pulmonary function among patients. Although MBL2 genotypes were associated with the MBL2 protein serum level, results were statistically significant only for polymorphisms in exon 1, with p = 0.0008. The role of the MBL2 gene in lung disease severity in CF patients represents a very complex phenomenon where both genetic and environmental factors play an important role in addition to that of the MBL2 gene. Understanding this complexity requires further studies based on a broader scale of genetic factors involving both a whole-genome approach and a larger patient cohort.

Modifier gene study of meconium ileus in cystic fibrosis: statistical considerations and gene mapping results.

Cystic fibrosis (CF) is a monogenic disease due to mutations in the CFTR gene. Yet, variability in CF disease presentation is presumed to be affected by modifier genes, such as those recently demonstrated for the pulmonary aspect. Here, we conduct a modifier gene study for meconium ileus (MI), an intestinal obstruction that occurs in 16-20% of CF newborns, providing linkage and association results from large family and case-control samples. Linkage analysis of modifier traits is different than linkage analysis of primary traits on which a sample was ascertained. Here, we articulate a source of confounding unique to modifier gene studies and provide an example of how one might overcome the confounding in the context of linkage studies. Our linkage analysis provided evidence of a MI locus on chromosome 12p13.3, which was segregating in up to 80% of MI families with at least one affected offspring (HLOD = 2.9). Fine mapping of the 12p13.3 region in a large case-control sample of pancreatic insufficient Canadian CF patients with and without MI pointed to the involvement of ADIPOR2 in MI (p = 0.002). This marker was substantially out of Hardy-Weinberg equilibrium in the cases only, and provided evidence of a cohort effect. The association with rs9300298 in the ADIPOR2 gene at the 12p13.3 locus was replicated in an independent sample of CF families. A protective locus, using the phenotype of no-MI, mapped to 4q13.3 (HLOD = 3.19), with substantial heterogeneity. A candidate gene in the region, SLC4A4, provided preliminary evidence of association (p = 0.002), warranting further follow-up studies. Our linkage approach was used to direct our fine-mapping studies, which uncovered two potential modifier genes worthy of follow-up.