CF Mutations Research Articles

Premodulator microbiome alterations associated with postmodulator growth outcomes in pediatric cystic fibrosis: Can we predict outcomes?

The gut microbiota plays an important role in childhood growth. Our longitudinal cohort includes children with cystic fibrosis (CwCF) treated with highly effective modulator therapy. We aimed to elucidate early premodulator microbial signatures associated with postmodulator weight for CwCF later in childhood. Stool samples were collected from CwCF at 13 days to 60 months. Metagenomic sequencing determined differentially abundant taxa. Children with body mass index or weight for length Z-scores within 1 standard deviation of the mean (SD) were considered normal weight, those >1 SD were classified as risk of overweight while children <1 SD were considered undernourished, although no CwCF met this latter criterion here. Multivariate regression models were applied to identify significant associations between metadata and microbial taxonomic relative abundances. One hundred and eighty-nine stool samples were analyzed from 39 CwCF. We identified statistically significant differences in early microbiome patterns among those at risk of being overweight compared to those who were normal weight when adjusted for age, sex, CF mutation, and early feeding method. Early microbiome was a stronger driver of growth status than current modulator use. Among those at risk of overweight, several taxa that were consistently in lower abundance included Eggerthella lentha, Ruminococcus, Bacteroides, with increase in abundance of Bacteroides stercoris. The early microbiome strongly predicts growth in the setting of modulator use for CwCF and we identify microbiome signatures associated with risk of being overweight. We highlight the possibility for interventions or early alternations to nutritional guidance for prevention of comorbid complications.

The clinical utility of sequencing the entirety of CFTR

BackgroundCystic fibrosis (CF) is caused by deleterious variants in each CFTR gene. We investigated the utility of whole-gene CFTR sequencing when fewer than two pathogenic or likely pathogenic (P/LP) variants were detected by conventional testing (sequencing of exons and flanking introns) of CFTR. MethodsIndividuals with features of CF and a CF-diagnostic sweat chloride concentration with zero or one P/LP variants identified by conventional testing enrolled in the CF Mutation Analysis Program (MAP) underwent whole-gene CFTR sequencing. Replication was performed on individuals enrolled in the CF Genome Project (CFGP), followed by phenotype review and interrogation of other genes. ResultsWhole-gene sequencing identified a second P/LP variant in 20/43 MAP enrollees (47 %) and 10/22 CFGP enrollees (45 %) who had one P/LP variant after conventional testing. No P/LP variants were detected when conventional testing was negative (MAP: n = 43; CFGP: n = 13). Genome-wide analysis was unable to find an alternative etiology in CFGP participants with fewer than two P/LP CFTR variants and CF could not be confirmed in 91 % following phenotype re-review. ConclusionsWhole-gene CFTR analysis is beneficial in individuals with one previously-identified P/LP variant and a CF-diagnostic sweat chloride. Negative conventional CFTR testing indicates that the phenotype should be re-evaluated.

Applying patient personalized organoid model system to understand complex GI manifestations in cystic fibrosis disease

Background: Stem cell-derived organotypic culture has become a revolutionary tool in transforming care for patients with multiple GI-disorders. Cystic fibrosis is a deadly genetic disorder with multiple GI complications, such as Distal intestinal obstruction syndrome (DIOS), chronic constipation, Gastroesophageal reflux disease (GERD), and in some cases pancreatitis, caused by loss of function mutations in the gene that encodes for the cystic fibrosis transmembrane conductance regulator (CFTR) chloride/bicarbonate ion channel. Due to genetic and environmental influences, CF patients exhibit large phenotypic variation. These factors make clinical trials difficult and largely impractical due to limited and heterogenous patient pools, and additionally, the benefit of approved small-molecule CF therapy in a large number of rare mutation patients is not known. Moreover, critical questions of whether CFTR contributes to the development of intestine and how it contributes to GI-related issues remain unanswered. Results: In this study, we performed a comprehensive bench-side study using in vitro patient enteroids and in vivo mice implanted Human Intestinal Organoids (HIOs) to test highly effective CFTR modulators -Ivacaftor response for a rare CF mutation patient. Based on the positive Ivacaftor response in the enteroids, the patient was enrolled in N=1 clinical trial and showed improved GI outcomes upon Ivacaftor treatment. HIO implantation model allowed in vivo modulator dosing and provided an elegant human organ-based demonstration of bench-to-bedside testing of modulator effects. Additionally, using the CF HIO model the role of CFTR function in the maturation of human intestine was reported for the first time. In HIOs derived from a stop mutation CF patient and CFTR-corrected HIOs as control, we performed single cell RNAseq analysis to generate a molecular map of GI-cell type specific transcriptomic alterations and identify key targetable pathways relevant to stop mutations in CFTR for which currently there is no small molecule therapy. Conclusion: In all, we demonstrate that these models effectively serve to translate data from the lab to the clinic and back so that patient specific therapies could be validated, or new therapies be devised. Additionally, single-cell RNA sequencing in patient HIOs will provide useful insights into cell population specific and transcriptomic level alterations that are associated with abnormalities in GI function in CF. Nothing to disclose This is the full abstract presented at the American Physiology Summit 2023 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

Identification of CF Mutations and Clinical Symptoms in CBAVD Patients

Identification of CF Mutations and Clinical Symptoms in CBAVD Patients

Determination of Cystic Fibrosis Mutation Frequency in Preterm and Term Neonates with Respiratory Tract Problems.

Cystic fibrosis (CF) is an autosomal recessive disease. The genetic transition occurs with CF transmembrane conductance regulator (CFTR) gene mutation. We aimed to determine the frequency of CF mutations and also new mutations in the CFTR gene in neonates with respiratory distress. Newborn babies hospitalized due to respiratory distress were included in the patient group. The control group consisted of infants who had no respiratory distress. The CFTR genes of both groups were analyzed using polymerase chain reaction (PCR) and restriction fragment length polymorphism (RFLP) methods. A total of 40 patients (20 in the patient group and 20 in the control group) were evaluated. The CFTR gene analysis was normal in 16 neonates in the patient group, whereas in others: A46D (c.137C>A) (n = 1), D1312G (c.3935A>G) (n = 1), R117H (c.350G>A) (n = 1), S1426P (c.4276T>C) (n = 1) heterozygotes were detected; CFTR gene analysis was normal at 14 neonates in the control group, whereas in others: E1228G (c.3683A>G) (n = 1), E217G (c.650A>G) (n = 1), E632TfsX9 (c1894_1895delAG) (n = 1), I807M (c.2421 A>G) (n = 2), S573F (c.1718C>T) (n = 1) heterozygotes were detected. There was no significant difference in the patient and control groups’ CFTR gene analysis (p = 0.340). This study demonstrates the importance of CFTR gene analysis in asymptomatic newborn infants for follow-up and early diagnosis of CFTR-related disorders. In this study, a c.1894_1895delAG (E632TfsX9) heterozygous mutation detected in the CFTR gene in an asymptomatic newborn infant, was first encountered in the literature.

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.

Role of Protein Kinase A-Mediated Phosphorylation in CFTR Channel Activity Regulation.

Cystic fibrosis transmembrane conductance regulator (CFTR) is an anion channel expressed on the apical membrane of epithelial cells, where it plays a pivotal role in chloride transport and overall tissue homeostasis. CFTR constitutes a unique member of the ATP-binding cassette transporter superfamily, due to its distinctive cytosolic regulatory (R) domain carrying multiple phosphorylation sites that allow the tight regulation of channel activity and gating. Mutations in the CFTR gene cause cystic fibrosis, the most common lethal autosomal genetic disease in the Caucasian population. In recent years, major efforts have led to the development of CFTR modulators, small molecules targeting the underlying genetic defect of CF and ultimately rescuing the function of the mutant channel. Recent evidence has highlighted that this class of drugs could also impact on the phosphorylation of the R domain of the channel by protein kinase A (PKA), a key regulatory mechanism that is altered in various CFTR mutants. Therefore, the aim of this review is to summarize the current knowledge on the regulation of the CFTR by PKA-mediated phosphorylation and to provide insights into the different factors that modulate this essential CFTR modification. Finally, the discussion will focus on the impact of CF mutations on PKA-mediated CFTR regulation, as well as on how small molecule CFTR regulators and PKA interact to rescue dysfunctional channels.

Patient personalized translational tools in cystic fibrosis to transform data from bench to bed-side and back.

Cystic fibrosis is a deadly multiorgan disorder caused by loss of function mutations in the gene that encodes for the cystic fibrosis transmembrane conductance regulator (CFTR) chloride/bicarbonate ion channel. More than 1,700 CFTR genetic variants exist that can cause CF, and majority of these are extremely rare. Because of genetic and environmental influences, CF patients exhibit large phenotypic variation. These factors make clinical trials difficult and largely impractical due to limited and heterogeneous patient pools. Also, the benefit of approved small-molecule CF modulators in a large number of rare mutation patients remains unknown. The goal of this study is to perform a comprehensive bench-side study using in vitro patient enteroids and in vivo mice implanted human intestinal organoids (HIOs) to test CF modulator-Ivacaftor response for a rare CF mutation patient. Based on the positive Ivacaftor response in the enteroids, the patient was enrolled in a (N = 1) clinical trial and showed improved clinical outcomes upon Ivacaftor treatment. HIO implantation model allowed in vivo modulator dosing and provided an elegant human organ-based demonstration of bench-to-bedside testing of modulator effects. Additionally, using the CF HIO model the role of CFTR function in the maturation of human intestine was reported for the first time. In all, we demonstrate that these models effectively serve to translate data from the lab to the clinic and back so that patient-specific therapies could be easily identified and disease-relevant developmental abnormalities in CF organs could be studied and addressed.NEW & NOTEWORTHY In this study, we report an example of laboratory models informing clinical care for rare CF mutation patient, with subsequent recapitulation of clinical benefit in a unique and disease relevant, human-derived in vivo model, effectively translating data from the lab to the clinic and back. This extensive work outlines a potential platform to identify patient-specific therapies and to understand relevant developmental abnormalities associated with CF disease.

Universal strategy for preimplantation genetic testing for cystic fibrosis based on next-generation sequencing.

We developed and applied a universal strategy for preimplantation genetic testing for all cystic fibrosis gene mutations (PGT-CF) based on next-generation sequencing (NGS). A molecular protocol was designed to diagnose all CF mutations at preimplantation stage. The detection of CF mutations was performed by direct gene sequencing and linkage strategy testing 38 specific SNPs located upstream and inside the gene for PGT-CF. Seventeen couples at risk of CF transmission decided to undergo PGT-CF. Trophectoderm cell biopsies were performed on days 5-6 blastocysts. PGT for aneuploidy (PGT-A) was performed from the same samples. Tested embryos were transferred on further natural cycles. PGT was performed on 109 embryos. Fifteen CF mutations were tested. PGT-CF and PGT-A were conclusive for, respectively, 92.7% and 95.3% of the samples. A mean of 24.1 SNPs was informative per couple. After single embryo transfer on natural cycle, 81.3% of the transferred tested embryos implanted. The present protocol based on the entire CFTR gene sequencingtogether with informative SNPs outside and inside the gene can be applied to diagnose all CF mutations at preimplantation stage.

Universal strategy for preimplantation genetic testing for cystic fibrosis based on next generation sequencing

PurposeWe developed and applied a universal strategy for preimplantation genetic testing for all cystic fibrosis gene mutations (PGT-CF) based on next-generation sequencing (NGS).MethodsA molecular protocol was designed to diagnose all CF mutations at preimplantation stage. The detection of CF mutations was performed by direct gene sequencing and linkage strategy testing 38 specific SNPs located upstream and inside the gene for PGT-CF. Seventeen couples at risk of CF transmission decided to undergo PGT-CF. Trophectoderm cell biopsies were performed on day 5–6 blastocysts. PGT for aneuploidy (PGT-A) was performed from the same samples. Tested embryos were transferred on further natural cycles.ResultsPGT was performed on 109 embryos. Fifteen CF mutations were tested. PGT-CF and PGT-A were conclusive for respectively 92.7% and 95.3% of the samples. A mean of 24.1 SNPs was informative per couple. After a single embryo transfer on natural cycle, 81.3% of the transferred tested embryos were implanted.ConclusionsThe present protocol based on the entire CFTR gene together with informative SNPs outside and inside the gene can be applied to diagnose all CF mutations at preimplantation stage.

Short-term consequences of F508del-CFTR thermal instability on CFTR-dependent transepithelial currents in human airway epithelial cells

Loss-of-function mutations in the Cystic Fibrosis Transmembrane conductance Regulator (CFTR) channel in human airway epithelial cells are responsible for Cystic Fibrosis. A deleterious impact of physiological temperature on CFTR plasma membrane expression, residence and channel activity is characteristic of the most common and severe CF mutation, F508del. Using primary human F508del-airway epithelial cells and CF bronchial epithelial CFBE41o- cell lines expressing F508del- or WT-CFTR, we examined the effects of temperature (29 °C-39 °C) on the amplitude and stability of short-circuit CFTR-dependent currents over time and the efficiency of pharmacological strategies to stably restore F508del-CFTR function. We show that F508del-CFTR functional instability at 37 °C is not prevented by low temperature or VX-809 correction, genistein and VX-770 potentiators, nor by the combination VX-809/VX-770. Moreover, F508del-CFTR-dependent currents 30 minutes after CFTR activation at 37 °C did not significantly differ whether a potentiator was used or not. We demonstrate that F508del-CFTR function loss is aggravated at temperatures above 37 °C while limited by a small decrease of temperature and show that the more F508del-CFTR is stimulated, the faster the current loss happens. Our study highlights the existence of a temperature-dependent process inhibiting the function of F508del-CFTR, possibly explaining the low efficacy of pharmacological drugs in clinic.

Metabonomics reveals altered metabolites related to inflammation and energy utilization at recovery of cystic fibrosis lung exacerbation

BackgroundCystic fibrosis lung disease is characterized by chronic bacterial infections in the setting of mucus abnormalities. Patients experience periodic exacerbations that manifest with increased respiratory symptoms that require intensification of therapy with enhanced airway clearance and intravenous (IV) antibiotics. ObjectivesIn an observational study we tested if the profile of metabolites in serum distinguished the pre-from post-exacerbation state and which systemically measurable pathways were affected during the process to recovery. MethodsSerum collected within 48 h of start and completion, respectively of IV antibiotics was collected from people with CF ages 6–30 years. Three day food records were collected prior to each sample. To reduce variation between subjects only subjects who had pancreatic insufficiency, had similar CF mutations, and did not have CF liver disease or diabetes were included. Metabolomic profiling was conducted by Ultrahigh Performance Liquid Chromatography-Tandem Mass Spectroscopy with metabolites being identified based on retention time/index, mass to charge ratio and comparison to known compounds. Biostatistical analyses used paired t-test with correction for multiple comparisons and orthogonal partial least square discriminant analysis. ResultsThirty subjects (20 male) with a mean ± SEM age of 15.3 ± 1.2 years participated, 17 of whom had matched food-records. Lung function was significantly improved post-therapy compared to pre-therapy, (mean ± SEM) 75 ± 4% vs. 68 ± 4% predicted (n = 26). Serum metabonomics showed distinction of the pre-vs. post-therapy groups with 123 compounds contributing to the differentiation pre-versus post-antibiotics by multiple biostatistical analyses. Compounds and pathways affected included bile acids and microbial derived amino acid metabolites, increases in lipid classes of the glycerophospholipid, glycerolipids, cholesterol, phopsholipids, and most pronounced, the class of sphingolipids. Changes in n6/n3 fatty acids, decreased polyamines but increased metabolites in the nitric oxide pathway, and changes in the tryptophan-kynurenine pathway indicated decreased inflammation at resolution of exacerbation. ConclusionsChanges in serum metabolites that distinguished CF pulmonary exacerbation vs. resolution of symptoms showed evidence of decreased inflammation and improvement from a catabolic state.

Advances in the Diagnosis and Management of Cystic Fibrosis in the Genomic Era.

Cystic fibrosis (CF) is a complex autosomal recessive disease that continues to present unique diagnostic challenges. Because CF was first described in 1938, there has been a substantial growth of genetic and phenotypic information about the disorder. During the past few years, as more evidence has become available, a consortium of international experts determined that the 2008 guidelines from the CF Foundation needed to be reviewed and updated. The goal of this review is to highlight the latest advances in CF multidisciplinary care, together with the recent updates to the 2017 CF Foundation diagnostic guidelines. Data from newborn screening programs, patient registries, clinical databases, and functional research have led to a better understanding of the CF transmembrane conductance regulator (CFTR) gene. Recent consensus guidelines have provided recommendations for clinicians and laboratorians to better assist with interpretation of disease status and related CF mutations. The highly recommended Clinical and Functional Translation of CFTR project should be the first resource in the evaluation of disease severity for CF mutations. Screen-positive newborns and patients with high clinical suspicion for CF are always recommended to undergo confirmatory sweat chloride testing with interpretations based on updated reference intervals. Every patient diagnosed with CF should receive genotyping, as novel molecular therapies are becoming standard of practice. The future of CF management must consider healthcare system disparities as CF transitions from a historically childhood disease to a predominantly adult epidemic.

IN VITRO AND IN SILICO CHARACTERIZATION OF HUMAN NASAL EPITHELIAL ION AND LIQUID TRANSPORT MECHANISMS

IntroductionCystic Fibrosis (CF) is a genetic disease caused by mutations in the CFTR gene, which codes for a widely expressed anion channel located in the apical membrane of epithelial cells. Loss of CFTR function results in an osmotic imbalance due to defective ion and water transport. Human bronchial epithelial cell cultures (HBE) are a well‐established experimental model of CF and show the same transport defects of the CF airway. More recently, human nasal epithelial cell cultures (HNE) have emerged as a novel alternative due to their accessibility and potential to allow for matched in vitro studies analogous to common clinical measurements. Here we implement a combination of experimental and computational approaches to facilitate the description of the ion and liquid transport functions of HNEs, and the role they may play in CF.MethodsWe have performed extensive characterization studies on well‐differentiated non‐CF HNE (n=9) and non‐CF HBE (n=12) to determine the extent of any possible physiological differences. This includes Ussing chamber studies to assess epithelial short‐circuit currents and resistance, apical volume regulation and paracellular flux assays, as measured by Tc99m‐DTPA (DTPA), to study response to volume challenges, and standard protein expression. We have also used this data to generate parametric fits of individual ion channel permeabilities, as predicted by a mathematical model of cell‐scale electrophysiology. Best parameter sets from each donor were estimated and compared against those from the opposite group to establish population differences according to a 2‐sample Kolmogorov‐Smirnov test.ResultsOur study shows HNE have a significant increase in the ENaC current (p&lt;0.05), and a decrease in stimulated CFTR current (p&lt;0.01) versus non‐CF HBEs. Similarly, thin film studies revealed significantly decreased DTPA retention, (p &lt; 0.05), as well as apical volume at 12 and 24 hrs following an apical volume challenge (p&lt;0.01). Donor‐specific parameter fits predicted statistically different parametric distributions for CFTR, ENaC, BKCa, and a basolateral Cl‐channel between the HBE and HNE population (p&lt;0.01). Of note are the increased basolateral Cl− and BKCA permeabilities relative to CFTR permeability.ConclusionOur studies showed non‐CF HNEs have higher liquid absorption rates than non‐CF HBEs. This behavior may be correlated with the lower CFTR dependent Cl− current also seen in HNE. It could suggest that HNEs operate at a different homeostatic level than HBEs due to environmental differences between the bronchi and the paranasal sinus, or perhaps it is the result of distinct functional levels of members of the epithelial electrophysiology network. Similar studies exploring the extent of these physiological differences in CF HNEs, and carriers of a single CF mutation, are currently underway.Support or Funding InformationSupported by NIH R01‐HL108929‐01, U01‐HL131046‐01, P30‐DK‐072506This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.

Partial rescue of F508del-cystic fibrosis transmembrane conductance regulator channel gating with modest improvement of protein processing, but not stability, by a dual-acting small molecule.

Rescue of F508del-cystic fibrosis (CF) transmembrane conductance regulator (CFTR), the most common CF mutation, requires small molecules that overcome protein processing, stability and channel gating defects. Here, we investigate F508del-CFTR rescue by CFFT-004, a small molecule designed to independently correct protein processing and channel gating defects. Using CFTR-expressing recombinant cells and CF patient-derived bronchial epithelial cells, we studied CFTR expression by Western blotting and channel gating and stability with the patch-clamp and Ussing chamber techniques. Chronic treatment with CFFT-004 improved modestly F508del-CFTR processing, but not its plasma membrane stability. By contrast, CFFT-004 rescued F508del-CFTR channel gating better than C18, an analogue of the clinically used CFTR corrector lumacaftor. Subsequent acute addition of CFFT-004, but not C18, potentiated F508del-CFTR channel gating. However, CFFT-004 was without effect on A561E-CFTR, a CF mutation with a comparable mechanism of CFTR dysfunction as F508del-CFTR. To investigate the mechanism of action of CFFT-004, we used F508del-CFTR revertant mutations. Potentiation by CFFT-004 was unaffected by revertant mutations, but correction was abolished by the revertant mutation G550E. These data suggest that correction, but not potentiation, by CFFT-004 might involve nucleotide-binding domain 1 of CFTR. CFFT-004 is a dual-acting small molecule with independent corrector and potentiator activities that partially rescues F508del-CFTR in recombinant cells and native airway epithelia. The limited efficacy and potency of CFFT-004 suggests that combinations of small molecules targeting different defects in F508del-CFTR might be a more effective therapeutic strategy than a single agent.

Synthesis and biological evaluation of novel thiazole- VX-809 hybrid derivatives as F508del correctors by QSAR-based filtering tools

The most common CF mutation, F508del, impairs the processing and gating of CFTR protein. This deletion results in the improper folding of the protein and its degradation before it reaches the plasma membrane of epithelial cells. Present correctors, like VX809 only induce a partial rescue of the mutant protein. Our previous studies reported a class of compounds, called aminoarylthiazoles (AATs), featuring an interesting activity as correctors. Some of them show additive effect with VX809 indicating a different mechanism of action. In an attempt to construct more interesting molecules, it was thought to generate chemically hybrid compounds, blending a portion of VX809 merged to the thiazole scaffold. This approach was guided by the development of QSAR analyses, which were performed based on the F508del correctors so far disclosed in the literature. This strategy was aimed at exploring the key requirements turning in the corrector ability of the collected derivatives and allowed us to derive a predictive model guiding for the synthesis of novel hybrids as promising correctors. The new molecules were tested in functional and biochemical assays on bronchial CFBE41o-cells expressing F508del-CFTR showing a promising corrector activity.

WS10.4 Performance of a four-step newborn screening strategy for CF in the Dutch screening program

Workshop. Since May 1, 2011, newborn screening for Cystic Fibrosis (NBSCF) is part of the Dutch NBS program Objectives: To assess the validity of the four-step screening strategy when applied in a routine newborn screening program. Methods: NBSCF was carried out as a 4-step strategy (Immunotrypsinogen (IRT)/Pancreatitis-associated Protein (PAP)/DNA-analysis for 35 CFTR mutations/extended gene analysis (EGA) (Thorax 2012;67: 289). As safety net EGA-analysis was performed in samples with IRT ≥ 100 μg/L but no CF mutations. In 2013 the strategy was adapted: besides newborns with two mutations, either disease-causing or of unknown clinical relevance, also newborns with one disease-causing mutation were referred to a designated CF centre for further diagnosis. Data analysis was carried out as if the screening strategy was adapted during the whole period of data collection (May 1, 2011 to January 1, 2016). CF centres reported results of sweat tests and CF patients not identified by NBSCF in the NBS-registry. Carriers and newborns with CFSPID were considered false positives. Before data-analysis a cross checkwas performed comparing data in the NBS- and the Dutch CF patient-registry. Results: 819,518 newborns, 99.95% of all newborns, were screened for CF; in 8,131 IRTwas ≥60 μg/L, in 1,079 DNA-analysis followed PAP analysis; 121 had 2 CF mutations; EGA analysis was performed in 85 samples with 1 CF mutation, in 474 as safety net. 193 were screen-positive. CF was confirmed in 122, we found 27 CFSPID, 37 carriers. CF was excluded in 7. A false negative screening test was reported for 16 (4 with meconium ileus (MI)), in 8 caused by PAP values < cut-off levels. We calculated a specificity of 99.99%, PPV 63%, CF/CFSPID ratio of 5/1 and a sensitivity of 91% (without MI). Conclusion: PAP as additional marker in NBSCF appears to lead to an excellent true/false positive rate and the finding of a low number of carriers. Lower PAP cut-off from 1–7-2016 can improve sensitivity to standards of care.

Genetics and genomic medicine in Cuba.

Genetics and genomic medicine in Cuba.

Nouvelles thérapeutiques ciblant le canal chlorure dans la mucoviscidose

Since the discovery of chloride secretion by the Cystic Fibrosis Transport regulator CFTR in 1983, and CFTR gene in 1989, knowledge about CFTR synthesis, maturation, intracellular transfer and function has dramatically expanded. These discoveries have led to the distribution of CF mutations into 6 classes with different pathophysiological mechanisms. In this article we will explore the state of art on CFTR synthesis and its chloride secretion function. We will then explore the consequences of the 6 classes of mutations on CFTR protein function and we will describe the new therapeutic developments aiming at correcting these defects.

263 Comparison of FEV1 and BMI of the 4 common CF mutations in UAE

263 Comparison of FEV1 and BMI of the 4 common CF mutations in UAE