Clinical efficacy of CFTR modulator therapy in people with cystic fibrosis carrying the I1234V mutation.

BACKGROUND: The cystic fibrosis transmembrane conductance regulator (CFTR) mutation I1234V (I1234V, p.Ile1234Val, c.3700A>G), is a missense-mutation that creates a cryptic splice site, with the formation of a protein lacking 6 amino acids, that is misfolded and misprocessed. The in vitro effects of CFTR modulator (CFTRm) therapies on human bronchial cell models and intestinal organoids carrying this mutation are conflicting. The aim of this study was therefore to explore the clinical efficacy of CFTRm in people with cystic fibrosis (pwCF) carrying this mutation. METHODS: This was a retrospective descriptive study of the clinical records of homozygous and compound heterozygous (none F508del) pwCF, for the I1234V mutation, that received CFTRm. Parameters explored were body mass index (BMI), forced expiratory volume in one second percent predicted (FEV1%), lung clearance index (LCI) and quantitative sweat chloride measurements. RESULTS: Mean age was 38.6 ± 14 years (range 21-60). Two subjects were homozygous and five compound heterozygous, with minimal function mutations. Four were pancreatic insufficient and three pancreatic sufficient. The two homozygous subjects received Tezacaftor/Ivacaftor, the remaining Elexacaftor/Tezacaftor/Ivacaftor (ETI); treatment ranged from 6 to 12 months. Mean BMI score increased from 21.7 ± 1.3 to 23.6 ± 2.1 kg/m2 (p = 0.04); FEV1(%pred) increased by 20.14±10.2while mean change in FEV1 in the year prior to CFTRm initiation was -0.14±1.18 (p = 0.0001). Additionally, LCI 2.5% decreased from 18.7 to 14.5 (p = 0.07); sweat chloride decreased from 116±10 to 90±17 mEq/L (p = 0.017) and chronic pseudomonas airway infection was eradicated in one subject. CONCLUSIONS: This study supports a clinical benefit for CFTRm therapy in pwCF carrying the I1234V mutation.

The new face of cystic fibrosis in the era of population genetic carrier screening.

BACKGROUND: Population genetic carrier screening (PGCS) for cystic fibrosis (CF) has been offered to couples in Israel since 1999 and was included in a fully subsidized national program in 2008. We evaluated the impact of PGCS on CF incidence, genetic and clinical features. METHODS: This was a retrospective national study. Demographic and clinical characteristics of children with CF born in Israel between 2008 and 2018 were obtained from the national CF registry and from patients' medical records. Data on CF births, preimplantation genetic testing (PGT), pregnancy termination and de-identified data from the PGCS program were collected. RESULTS: CF births per 100,000 live births decreased from 8.29 in 2008 to 0.54 in 2018 (IRR = 0.84, p < 0.001). The CF pregnancy termination rate did not change (IRR = 1, p=  0.9) while the CF-related PGT rate increased markedly (IRR = 1.33, p < 0.001). One hundred and two children were born with CF between 2008 and 2018 with a median age at diagnosis of 4.8 months, range 0-111 months. Unlike the generally high uptake nationally, 65/102 had not performed PGCS. Even if all had utilized PGCS, only 51 would have been detected by the existing genetic screening panel. Clinically, 34 % of children were pancreatic sufficient compared to 23 % before 2008 (p = 0.04). CONCLUSIONS: Since institution of a nationwide PGCS program, the birth of children with CF decreased markedly. Residual function variants and pancreatic sufficiency were more common. A broader genetic screening panel and increased PGCS utilization may further decrease the birth of children with CF.

Congenital Central Hypoventilation Syndrome in Israel-Novel Findings from a New National Center.

BACKGROUND: Congenital central hypoventilation syndrome (CCHS) is a rare autosomal-dominant disorder of the autonomic nervous system that results from mutations in the PHOX2B gene. A national CCHS center was founded in Israel in 2018. Unique new findings were observed. METHODS: All 27 CCHS patients in Israel were contacted and followed. Novel findings were observed. RESULTS: The prevalence of new CCHS cases was almost twice higher compared to other countries. The most common mutations in our cohort were polyalanine repeat mutations (PARM) 20/25, 20/26, 20/27 (combined = 85% of cases). Two patients showed unique recessive inheritance while their heterozygotes family members were asymptomatic. A right-sided cardio-neuromodulation was performed on an eight-year-old boy for recurrent asystoles by ablating the parasympathetic ganglionated plexi using radiofrequency (RF) energy. Over 36 months' follow-up with an implantable loop-recorder, no bradycardias/pauses events were observed. A cardiac pacemaker was avoided. CONCLUSIONS: A significant benefit and new information arise from a nationwide expert CCHS center for both clinical and basic purposes. The incidence of CCHS in some populations may be increased. Asymptomatic NPARM mutations may be much more common in the general population, leading to an autosomal recessive presentation of CCHS. RF cardio-neuromodulation offers a novel approach to children avoiding the need for permanent pacemaker implantation.

Antimicrobial Peptides against Multidrug-Resistant Pseudomonas aeruginosa Biofilm from Cystic Fibrosis Patients.

Lung infection is the leading cause of morbidity and mortality in cystic fibrosis (CF) patients and is mainly dominated by Pseudomonas aeruginosa. Treatment of CF-associated lung infections is problematic because the drugs are vulnerable to multidrug-resistant pathogens, many of which are major biofilm producers like P. aeruginosa. Antimicrobial peptides (AMPs) are essential components in all life forms and exhibit antimicrobial activity. Here we investigated a series of AMPs (d,l-K6L9), each composed of six lysines and nine leucines but differing in their sequence composed of l- and d-amino acids. The d,l-K6L9 peptides showed antimicrobial and antibiofilm activities against P. aeruginosa from CF patients. Furthermore, the data revealed that the d,l-K6L9 peptides are stable and resistant to degradation by CF sputum proteases and maintain their activity in a CF sputum environment. Additionally, the d,l-K6L9 peptides do not induce bacterial resistance. Overall, these findings should assist in the future development of alternative treatments against resistant bacterial biofilms.

Spontaneous pneumothorax-When do we need to intervene?

BACKGROUND: Pneumothorax can be classified as traumatic, iatrogenic or spontaneous (SP), which can be subdivided into primary spontaneous pneumothorax (PSP), a condition without preexisting lung disease, or secondary spontaneous pneumothorax (SSP) a complication of a preexisting lung disease. Recurrence rate of PSP is 30% whereas for SSP rate is unknown. This article explores the experience of a tertiary center over 20 years. METHODS: A retrospective case review of patients hospitalized with pneumothorax to investigate the natural history and treatment of SP in a young population in a single tertiary center was conducted. A search of the digital archive (going back to 01/01/1995) of Sheba Medical Center identified hospitalized patients below the age of 40. RESULTS: The database was composed of the records of 750 patients (612 males, 138 females) who were hospitalized. The recurrence risk for SP after nonoperative treatment was significantly higher. Women were found to have an increased risk of SSP when having SP (OR 2.78). Asthma was the most prevalent disease causing SSP in young people. CONCLUSIONS: In this large cohort, we found that operative procedure has clear protective effect from recurrence in SP, so surgery should be positively considered when treating SP in hospitalized patients. Among young people and particularly in pediatric patients, when females have a SP, we strongly recommend looking for primary lung disease. More studies are needed to determine the risk factors and produce clear guidelines regarding surgery as first treatment.

Advanced Lung Disease in Patients with Cystic Fibrosis Is Associated with Low Diffusion capacity.

BACKGROUND: The single-breath diffusing capacity of the lungs (DLCOSB) test measures the extent to which carbon monoxide (CO) passes from the lung air sacs into the blood. The accessible alveolar volume (VASB) is measured by inert gas during a 10-second period. The single-breath transfer coefficient of the lung for carbon monoxide (KCOSB) is the DLCOSB divided by VASB. Cystic fibrosis (CF) disease comprises progressive airway obstruction with bronchiectasis and parenchyma fibrosis. Yet, the KCOSB appears insignificant in the assessment of pulmonary function in CF. OBJECTIVES: To challenge the precision of normal KCOSB in CF. METHODS: The authors collected pulmonary function tests (PFT) data from 74 confirmed CF patients (mean age 26 ± 10 years) with various levels of pulmonary disease severity. Tests included spirometry, DLCOBP, and body plethysmography (BP). Anatomical dead space was calculated by deducting anatomical dead space from total lung capacity TLC(BP) to establish alveolar volume (VABP) and to determine KCOBP. We also included individual data of arterial pCO2 blood-gas level. RESULTS: KCOSB values were normal or higher in most patients, regardless of patient FEV1 value (R2 = 0.2204; P < 0.02). In contrast, the measurements of KCOBP were low corresponding with low FEV1 values, and negatively correlated with the elevation of trapped air and pCO2 levels (R2 = 0.1383; P = 0.0133, P > 0.05, respectively). CONCLUSIONS: The 10- second perfusion time of the inert gas during DLCOSB represent the communicative alveolar volume in CF patients with advanced pulmonary disease. The findings justify the use of DLCOSB with the deterioration of FEV1 and elevation of pCO2 levels.

Author Correction: Inhaled nitric oxide therapy in acute bronchiolitis: A multicenter randomized clinical trial.

An amendment to this paper has been published and can be accessed via a link at the top of the paper.

Phenotypic and molecular characteristics of CF patients carrying the I1234V mutation.

BACKGROUND: The Mutation I1234V is a CF causing mutation; however the mechanisms leading to loss of function are not fully understood. In this study, we aimed to characterize phenotypically individuals with the I1234V variant, and to gain a structural point of view of the mutant CFTR using computational studies. METHODS: We conducted a retrospective descriptive study, reviewing the clinical records of 9 Israeli patients. The study was designed to include patients either homozygous or compound heterozygous for the I1234V mutation. For a comparison we analyzed clinical data of 12 patients homozygous for the F508del mutation. Computer models were constructed for I1234V, 1234-1239del and wild type CFTR. RESULTS: Mean FEV1 was 73.8 ± 21% predicted with an average annual rate of decline of 1%. When compared to patients homozygous for F508del the mean annual values of FEV1% predicted during the 6 years of data collection ranged from 51 to 58 ± 22-30 in the F508del group versus 76-82 ± 14-19 in the I1234V group (p < 0.05). Structural models did not demonstrate noticeable differences between the three simulated constructs. Although the mutation resides in the NBD2, no interference with ATP binding was detected. DISCUSSION: This study describes phenotypically patients carrying the I1234V mutation. Compared to patients homozygous for F508del, these patients present with more favorable outcome. Structural models show high similarity between the static and dynamics pictures obtained for both the mutated and the WT-CFTR; however this model does not explore the folding process and therefore may strengthen the notion of a misfolding mutation.

The benefits of mechanical insufflator-exsufflator compared to autogenic drainage in adults with cystic fibrosis.

BACKGROUND: Autogenic drainage (AD) is used for airway clearance in individuals with cystic fibrosis (CF). The mechanical insufflator-exsufflator (MI-E) device is commonly used in patients with neuromuscular diseases for airway clearance by increasing inspiratory volume and expiratory flow. MI-E use has not been studied extensively in CF patients. OBJECTIVES: To examine whether there are advantages to using the MI-E device in patients with CF. SUBJECTS: Fourteen males and eight females from the national center for CF, with an average FEV1 of 54% were recruited DESIGN: Prospective cross-over trial (IRB 3009-16-SMC). INTERVENTION: Subjects received either AD or MI-E in a random order. Sputum was collected and weighed immediately after treatment. Subjects performed lung function tests at baseline, 20 minutes after and 1 hour after treatment; additionally, a 2-minute walk test was performed at the end of all lung function tests. Saturation, dyspnea scores while resting and after a 2-minute walk and subjective fatigue were recorded. RESULTS: Thirty-six percent more sputum was collected following MI-E than AD treatment (P < .0001). A significant difference in saturation in response to the 2MWT was noted in both treatments significantly less desaturation was recorded after the 2MWT in the MI-E treatment (P < .01). CONCLUSIONS: Treatment with the MI-E was more effective for clearing sputum in CF subjects, initial evidence suggests that the MI-E may be successfully incorporated into treatment protocols. Further studies are needed to assess the long-term benefits of MI-E in patients with CF.

Inhaled nitric oxide therapy in acute bronchiolitis: A multicenter randomized clinical trial.

Currently, there are no approved treatments for infants with acute bronchiolitis, the leading cause for hospitalization of infants worldwide, and thus the recommended approach is supportive. Inhaled Nitric oxide (iNO), possesses anti-viral properties, improves oxygenation, and was shown to be safe in infants with respiratory conditions. Hospitalized infants with acute bronchiolitis were therefore recruited to a prospective double-blinded, multi-center, randomized controlled pilot study. They received intermittent high dose iNO (160 ppm) plus oxygen/air for 30 min or oxygen/air alone (control), five times/day, up to 5 days. Sixty-nine infants were enrolled. No difference was observed in frequencies of subjects with at least one Adverse Event (AE) in iNO (44.1%) vs. control (55.9%); neither was Methemoglobin >7% safety threshold. No drug-related serious AEs (SAEs) were reported. Analysis of Per-Protocol population revealed that length of stay (LOS), time to SpO2 ≥92%, and time to mTal clinical score ≤5 improved by 26.7 ± 12.7 (Welch's t-test p = 0.04), 20.8 ± 8.9 (p = 0.023), and 14.6 ± 9.1 (p = 0.118) hours, respectively, in the iNO group compared to the control. Overall, high dose iNO (160ppm) was safe, well-tolerated, reduced LOS and showed rapid improvement of oxygen saturation, compared to the standard therapy. Further investigation in larger cohorts is warranted to validate these encouraging efficacy outcomes. (Trial registration: NCT03053388).

Correction to: Ambulatory blood pressure profiles in familial dysautonomia.

Unfortunately, the original version of this article contained.

Pilot study to test inhaled nitric oxide in cystic fibrosis patients with refractory Mycobacterium abscessus lung infection.

BACKGROUND: Airways of Cystic Fibrosis (CF) patients are Nitric Oxide (NO) deficient which may contribute to impaired lung function and infection clearance. Mycobacterium abscessus (M. abscessus) infection prevalence is increasing in CF patients and is associated with increased morbidity and mortality. Here, we assess the safety and efficacy of intermittent inhaled NO (iNO) as adjuvant therapy in CF patients with refractory M. abscessus lung infection. METHODS: A prospective, open-label pilot study of iNO (160 ppm) administered five times/day during hospitalization (14 days), and three times/day during ambulatory treatment (7 days) was conducted. The primary outcome was safety measured by NO-related adverse events (AEs). Secondary outcomes were six-minute walk distance (6MWD), forced expiratory volume in 1 s (FEV1), and M. abscessus burden in airways. RESULTS: Nine subjects were recruited. INO at 160 ppm was well-tolerated and no iNO-related SAEs were observed during the study. Mean FEV1 and 6WMD were increased relative to baseline during NO treatment. M. abscessus culture conversion was not achieved, but 3/9 patients experienced at least one negative culture during the study. Mean time to positivity in M. abscessus culture, and qPCR analysis showed reductions in sputum bacterial load. The study was not powered to achieve statistical significance in FEV1, 6WMD, and bacterial load. CONCLUSIONS: Intermittent iNO at 160 ppm is well tolerated and safe and led to increases in mean 6MWD and FEV1. INO exhibited potential antibacterial activity against M. abscessus. Further evaluation of secondary endpoints in a larger cohort of CF patients is warranted to demonstrate statistical significance.

Resting Energy Expenditure in Patients With Familial Dysautonomia: A Preliminary Study.

OBJECTIVES: Familial dysautonomia (FD) is a rare hereditary sensory and autonomic neuropathy characterized by chronic lung disease and cyclic vomiting due to hyper-adrenergic crises. Most FD patients are in a depleted nutritional state; however, the phenotype of the disease is quite different between patients, as for the severity of lung disease and the intensity and frequency of these pathognomonic crises. In this study we wanted to investigate whether resting energy expenditure (REE) levels are increased in this population, and if correlations exist between REE levels and phenotype severity. METHODS: Data was collected from 12 FD patients (6/6 m/f). REE measurements were conducted by indirect calorimeter. Measured REE % predicted were correlated with pulmonary function, severity of the scoliosis, serum C-reactive protein, yearly frequency of hyperadrenergic crisis, hospital admissions and the use of nocturnal noninvasive positive pressure ventilation. RESULTS: Mean REE was 112 ±13% predicted with 50% being in a hypermetabolic state (REE/HB > 110%). Body mass index (BMI) was below normal range in 75% of patients, and reduced energy intake was also decreased in 75%. No significant correlations to disease severity factors were found. When dividing the subjects to REE levels above or below 125% predicted, Patients with REE above 125% predicted presented with significantly lower inspiratory capacity (42.7% predicted vs 62.8% predicted; P = 0.04). CONCLUSIONS: Hypermetabolic state was described in 50% of FD patients. The Low BMI is explained by combination of relative anorexia and increased REE. The REE levels are related to the underling respiratory disease.

Respiratory care in familial dysautonomia: Systematic review and expert consensus recommendations.

BACKGROUND: Familial dysautonomia (Riley-Day syndrome, hereditary sensory autonomic neuropathy type-III) is a rare genetic disease caused by impaired development of sensory and afferent autonomic nerves. As a consequence, patients develop neurogenic dysphagia with frequent aspiration, chronic lung disease, and chemoreflex failure leading to severe sleep disordered breathing. The purpose of these guidelines is to provide recommendations for the diagnosis and treatment of respiratory disorders in familial dysautonomia. METHODS: We performed a systematic review to summarize the evidence related to our questions. When evidence was not sufficient, we used data from the New York University Familial Dysautonomia Patient Registry, a database containing ongoing prospective comprehensive clinical data from 670 cases. The evidence was summarized and discussed by a multidisciplinary panel of experts. Evidence-based and expert recommendations were then formulated, written, and graded using the Grading of Recommendations, Assessment, Development, and Evaluation (GRADE) system. RESULTS: Recommendations were formulated for or against specific diagnostic tests and clinical interventions. Diagnostic tests reviewed included radiological evaluation, dysphagia evaluation, gastroesophageal evaluation, bronchoscopy and bronchoalveolar lavage, pulmonary function tests, laryngoscopy and polysomnography. Clinical interventions and therapies reviewed included prevention and management of aspiration, airway mucus clearance and chest physical therapy, viral respiratory infections, precautions during high altitude or air-flight travel, non-invasive ventilation during sleep, antibiotic therapy, steroid therapy, oxygen therapy, gastrostomy tube placement, Nissen fundoplication surgery, scoliosis surgery, tracheostomy and lung lobectomy. CONCLUSIONS: Expert recommendations for the diagnosis and management of respiratory disease in patients with familial dysautonomia are provided. Frequent reassessment and updating will be needed.

The Value of Measuring Inspiratory Capacity in Subjects With Cystic Fibrosis.

BACKGROUND: Inspiratory capacity (IC) is often overlooked as an important measured index of spirometry in patients with cystic fibrosis (CF). Abnormally low IC may indicate the onset of static/dynamic hyperinflation, which may be accompanied by dyspnea and an increase in the work of breathing. This cross-sectional study sought to determine whether measuring IC during spirometry, may add clinical value to FEV1 measurements in CF subjects. METHODS: Anthropometric, clinical, spirometry, and static lung volume data were gathered retrospectively from 98 of 165 subjects with CF (mean ± SD age 26.8 ± 11.0 y) registered in The Edmond and Lily Safra Children's Hospital, Sheba Medical Centre, Israel. We compared the IC (% predicted) to FEV1, static lung volumes, and hospitalization days/year. RESULTS: IC decreased alongside FEV1 decline but at a slower pace (r2 = 0.32). Incremental trapped air, as measured by residual volume (RV), and a rapid elevation in the ratio of RV to total lung capacity occurred when IC deteriorated below 60% predicted values. The unique combination of IC < 50% predicted and FEV1 > 40% predicted induced an increase of up to 125 hospitalization days/year compared to subjects having IC > 50% predicted (up to 73 d/y, P < .001). CONCLUSIONS: Measuring IC in CF subjects may reveal silent worsening of lung function as indicated by a decline in IC < 50% predicted while FEV1 is still > 40% predicted. This condition may lead to inefficient breathing at high lung volumes, which may explain a subjective sensation of breathlessness and lead to an increase in hospitalization days/year.

Omalizumab in allergic bronchopulmonary aspergillosis in patients with cystic fibrosis.

BACKGROUND: Allergic bronchopulmonary aspergillosis (ABPA) is a condition characterized by a Th2 response, serum eosinophilia, and increased total serum IgE to Aspergillus fumigatus. ABPA occurs in cystic fibrosis (CF) and asthma. Omalizumab is a humanized recombinant monoclonal antibody against IgE. Previous studies reported borderline results when treating ABPA with omalizumab. METHODS: A retrospective study to investigate the efficacy of omalizumab in the treatment of ABPA in CF patients was conducted at 3 CF centers in Israel and Belgium. Data were obtained from the digital archive. We measured 4 outcome parameters: forced expiratory volume in 1 second, body mass index, pulmonary exacerbations, and steroid sparing. RESULTS: The database was composed on the records of 9 patients. None of the outcome parameters showed any improvement. A favorable outcome was observed in patients with higher levels of posttreatment total IgE than those with lower levels. CF-related diabetes and male gender showed trends for poorer outcomes. CONCLUSION: No benefits were detected on treating ABPA in CF with omlaizumb. Monitoring the total IgE was not helpful. A prospective randomized double-blind study is needed.

Ambulatory blood pressure profiles in familial dysautonomia.

OBJECTIVE: Familial dysautonomia (FD) is a rare genetic disease that involves extreme blood pressure fluctuations secondary to afferent baroreflex failure. The diurnal blood pressure profile, including the average, variability, and day-night difference, may have implications for long-term end organ damage. The purpose of this study was to describe the circadian pattern of blood pressure in the FD population and relationships with renal and pulmonary function, use of medications, and overall disability. METHODS: We analyzed 24-h ambulatory blood pressure monitoring recordings in 22 patients with FD. Information about medications, disease severity, renal function (estimated glomerular filtration, eGFR), pulmonary function (forced expiratory volume in 1 s, FEV1) and an index of blood pressure variability (standard deviation of systolic pressure) were analyzed. RESULTS: The mean (± SEM) 24-h blood pressure was 115 ± 5.6/72 ± 2.0 mmHg. The diurnal blood pressure variability was high (daytime systolic pressure standard deviation 22.4 ± 1.5 mmHg, nighttime 17.2 ± 1.6), with a high frequency of a non-dipping pattern (16 patients, 73%). eGFR, use of medications, FEV1, and disability scores were unrelated to the degree of blood pressure variability or to dipping status. INTERPRETATION: This FD cohort had normal average 24-h blood pressure, fluctuating blood pressure, and a high frequency of non-dippers. Although there was evidence of renal dysfunction based on eGFR and proteinuria, the ABPM profile was unrelated to the measures of end organ dysfunction or to reported disability.

A Controlled Trial of Inhaled Bronchodilators in Familial Dysautonomia.

BACKGROUND: Chronic lung disease is a leading cause of premature death in patients with familial dysautonomia (FD). A significant number of patients have obstructive airway disease, yet it is not known whether this is pharmacologically reversible. METHODS: We conducted a double-blind, placebo-controlled, randomized clinical trial comparing the beta 2 agonist albuterol with the muscarinic blocker ipratropium bromide in patients homozygous for the IKBKAP founder mutation. Albuterol, ipratropium bromide, and placebo were administered on 3 separate days via nebulizer in the seated position. Airway responsiveness was evaluated using spirometry and impulse oscillometry 30 min post dose. Cardiovascular effects were evaluated by continuous monitoring of blood pressure, RR intervals, cardiac output, and systemic vascular resistance. RESULTS: A total of 14 patients completed the trial. Neither active agent had significant detrimental effects on heart rate or rhythm or blood pressure. Albuterol and ipratropium were similar in their bronchodilator effectiveness causing significant improvement in forced expiratory volume in 1-s (FEV1, p = 0.002 and p = 0.030). Impulse oscillometry measures were consistent with a reduction in total airway resistance post nebulization (resistance at 5 Hz p < 0.006). CONCLUSION: Airway obstruction is pharmacologically reversible in a number of patients with FD. In the short term, both albuterol and ipratropium were well tolerated and not associated with major cardiovascular adverse events.

Ivacaftor for the p.Ser549Arg (S549R) gating mutation - The Israeli experience.

BACKGROUND: Ivacaftor is a drug that increases the probability of the cystic fibrosis transmembrane conductance regulator (CFTR) chloride channel remaining open. Information about the efficacy of ivacaftor in patients carrying the rare p.Ser549Arg (S549R) CFTR mutation is sparse. AIM: Efficacy of ivacaftor treatment in patients carrying the p.Ser549Arg (S549R) CFTR mutation. METHODS: Data obtained from CF patients receiving ivacaftor for one year. RESULTS: Eight CF patients, mean age 21 ± 10 years, received ivacaftor. After one year, significant improvement was found in FEV1, increasing from 74% to 88% (p < 0.001), FVC, 89% to 101% (p = 0.019), and FEF25-75, 59%-76% (p = 0.019). Sweat chloride concentration decreased from 116 ± 8 mmol/L to 51 ± 17 mmol/L (p < 0.001), and BMI increased from 20 ± 3 to 22 ± 4 (p = 0.003). Glucose tolerance improved in five patients. There was no significant change in bacterial colonization. CONCLUSIONS: Ivacaftor therapy resulted in significant clinical improvement in patients carrying the p.Ser549Arg (S549R) CFTR mutation.

Nationwide genetic analysis for molecularly unresolved cystic fibrosis patients in a multiethnic society: implications for preconception carrier screening.

BACKGROUND: Preconception carrier screening for cystic fibrosis (CF) is usually performed using ethnically targeted panels of selected mutations. This has been recently challenged by the use of expanded, ethnically indifferent, pan-population panels. Israel is characterized by genetically heterogeneous populations carrying a wide range of CFTR mutations. To assess the potential of expanding the current Israeli preconception screening program, we sought the subset of molecularly unresolved CF patients listed in the Israeli CF data registry comprising ~650 patients. METHODS: An Israeli nationwide genotyping of 152 CF cases, representing 176 patients lacking molecular diagnosis, was conducted. Molecular analysis included Sanger sequencing for all exons and splice sites, multiplex ligation probe amplification (MLPA), and next-generation sequencing of the poly-T/TG tracts. RESULTS: We identified 54 different mutations, of which only 16 overlapped the 22 mutations included in the Israeli preconception screening program. A total of 29/54 (53.7%) mutations were already listed as CF causing by the CFTR2 database, and only 4/54 (7.4%) were novel. Molecular diagnosis was reached in 78/152 (51.3%) cases. Prenatal diagnosis of 24/78 (30.8%) cases could have been achieved by including all CFTR2-causing mutations in the Israeli panel. CONCLUSIONS: Our data reveal an overwhelming hidden abundance of CFTR gene mutations suggesting that expanded preconception carrier screening might achieve higher preconception detection rates.