CFTR Genotype Research Articles

Non pathological sweat test, pancreatic insufficiency and Cystic Fibrosis: an unusual case in a child with F508del-duplication of exons 1–3 CFTR genotype

While Cystic Fibrosis is characterized by a high phenotypic variability, a correlation is reported between the pancreatic status and the CFTR genotype. Here we report an unusual case of a child with Cystic Fibrosis (F508del-duplication of exons 1–3 genotype) diagnosed at 8 years old for pancreatic insufficiency and non-pathological sweat test, in absence of respiratory symptoms and acute episodes of pancreatitis. Nasal potential differences and intestinal current measurements were normal, while the short-circuit current measured on patient-derived colonoids grown on Transwell® indicated the presence of a reduced CFTR-dependent current relative to non-CF colonoids with, a modest improvement of CFTR activity record following treatment with elexacaftor/tezacaftor/ivacaftor.This case opens the discussion on the importance of performing CFTR sequencing and the search for large gene rearrangements in cases of pancreatic insufficiency of unclear etiology, also in the presence of non-pathological sweat test. Children with CF and non-pathological sweat chloride are likely to develop higher concentrations if they truly have CF.

Gene expression profile of intestinal organoids from people with cystic fibrosis upon exposure to elexacaftor/tezacaftor/ivacaftor

The forskolin-induced swelling assay (FIS) in patient-derived intestinal organoids (PDIOs), used to determine in vitro responsiveness to elexacaftor/tezacaftor/ivacaftor (ETI), showed variability in swelling among PDIOs obtained from people with CF (pwCF) carrying the same F508del/F508del CFTR genotype. We aimed to characterise the effect of ETI on the transcriptional activity of PDIOs-derived cells to understand the intracellular processes triggered by ETI and the differences in treatment response. Six high- and six low-responding PDIOs to ETI, derived from F508del/F508del pwCF, were incubated with or without ETI for 2 to 6 h. Gene expression was assessed using 3′-mRNA sequencing and modelled using negative binomial models. Incubation with ETI resulted in a significant upregulation of several biological processes: mostly related to chemokines and signalling, chemotaxis, and tissue development processes. No changes were observed in abundance of the CFTR transcripts or in CFTR-related gene sets and pathways. The genes and pathways associated with ETI did not overlap with those whose expression changed with time only. PDIOs with a high FIS response did not significantly differ in any interpretable gene from the FIS-low organoids. The changes in the PDIOs gene expression upon the exposure to ETI cannot explain differences in the magnitude of PDIOs FIS-measured response to ETI. In conclusion, on incubation with ETI, genes of the CFTR-related pathways do not change their transcriptional activity; instead, overexpression was observed in genes of inflammatory-like cytokine response and receptor activation pathways.

Establishment of a conditionally reprogrammed primary eccrine sweat gland culture for evaluation of tissue-specific CFTR function

BackgroundSweat chloride concentration is used both for CF diagnosis and for tracking CFTR modulator efficacy over time, but the relationship between sweat chloride and lung health is heterogeneous and informed by CFTR genotype. Here, we endeavored to characterize ion transport in eccrine sweat glands (ESGs). MethodsFirst, ESGs were microdissected from a non-CF skin donor to analyze individual glands. We established primary cultures of ESG cells via conditional reprogramming for functional testing of ion transport by short circuit current measurement and examined cell composition by single-cell RNA-sequencing (scRNA-seq) comparing with whole dissociated ESGs. Secondly, we cultured nasal epithelial (NE) cells and ESGs from two people with CF (pwCF) to assess modulator efficacy. Finally, NEs and ESGs were grown from one person with the CFTR genotype F312del/F508del to explore genotype-phenotype heterogeneity. ResultsESG primary cells from individuals without CF demonstrated robust ENaC and CFTR function. scRNA-seq demonstrated both secretory and ductal ESG markers in cultured ESG cells. In both NEs and ESGs from pwCF homozygous for F508del, minimal baseline CFTR function was observed, and treatment with CFTR modulators significantly enhanced function. Notably, NEs from an individual bearing F312del/F508del exhibited significant baseline CFTR function, whereas ESGs from the same person displayed minimal CFTR function, consistent with observed phenotype. ConclusionsThis study has established a novel primary culture technique for ESGs that allows for functional ion transport measurement to assess modulator efficacy and evaluate genotype-phenoytpe heterogeneity. To our knowledge, this is the first reported application of conditional reprogramming and scRNA-seq of microdissected ESGs.

WS15.02 Real-world effectiveness of elexacaftor/tezacaftor/ivacaftor (ELX/TEZ/IVA) in people with cystic fibrosis and ELX/TEZ/IVA-responsive, non-F508del CFTR genotypes

WS15.02 Real-world effectiveness of elexacaftor/tezacaftor/ivacaftor (ELX/TEZ/IVA) in people with cystic fibrosis and ELX/TEZ/IVA-responsive, non-F508del CFTR genotypes

WS02.03 Disease burden in people with cystic fibrosis according to CFTR genotype and eligibility to CFTR modulator therapy: a ECFS Patient Registry analysis

WS02.03 Disease burden in people with cystic fibrosis according to CFTR genotype and eligibility to CFTR modulator therapy: a ECFS Patient Registry analysis

Repeatability and reproducibility of the Forskolin-induced swelling (FIS) assay on intestinal organoids from people with Cystic Fibrosis

BackgroundThe forskolin-induced swelling (FIS) assay measures CFTR function on patient-derived intestinal organoids (PDIOs) and may guide treatment selection for individuals with Cystic Fibrosis (CF). The aim of this study is to demonstrate the repeatability and reproducibility of the FIS assay following a detailed Standard Operating Procedure (SOP), thus advancing the validation of the assay for precision medicine (theranostic) applications. MethodsOver a 2-year period, FIS responses to CFTR modulators were measured in four European labs. PDIOs from six subjects with CF carrying different CFTR genotypes were used to assess the repeatability and reproducibility across the dynamic range of the assay. ResultsTechnical, intra-assay repeatability was high (Lin's concordance correlation coefficient (CCC) 0.95–0.98). Experimental, within-subject repeatability was also high within each lab (CCCs all >0.9). Longer-term repeatability (>1 year) showed more variability (CCCs from 0.67 to 0.95). The reproducibility between labs was also high (CCC ranging from 0.92 to 0.97). Exploratory analysis also found that between-lab percentage of agreement of dichotomized CFTR modulator outcomes for predefined FIS thresholds ranged between 78 and 100 %. ConclusionsThe observed repeatability and reproducibility of the FIS assay within and across different labs is high and support the use of FIS as biomarker of CFTR function in the presence or absence of CFTR modulators.

Heterogeneity in response to Elexacaftor/Tezacaftor/Ivacaftor in people with cystic fibrosis

BackgroundHighly effective modulators of the CFTR channel have been demonstrated to dramatically impact disease progression and outcome. However, real-world data indicates that the magnitude of the clinical benefit is not equal among all patients receiving the treatment. We aimed to assess the variability in treatment response (as defined by the 6-month change in sweat chloride concentration, forced expiratory volume in one second [ppFEV1], body mass index [BMI], and CF Questionnaire-Revised [CFQ-R] respiratory domain score) and identify potential predictors in a group of patients receiving Elexacaftor-Tezacaftor-Ivacaftor (ETI) triple combination therapy. MethodsThis was a single-center, prospective cohort study enrolling adults with CF at a major center in Italy. We used linear regression models to identify a set of potential predictors (including CFTR genotype, sex, age, and baseline clinical characteristics) and estimate the variability in treatment response. ResultsThe study included 211 patients (median age: 29 years, range: 12–58). Median changes (10–90th percentile) from baseline were: - 56 mEq/L (–76; –27) for sweat chloride concentration, +14.5 points (2.5; 32.0) for ppFEV1, +0.33 standard deviation scores (–0.13; 1.05) for BMI and +17 points (0; 39) for the CFQ-R respiratory domain score. The selected predictors explained 23 % of the variability in sweat chloride concentration changes, 18 % of the variability in ppFEV1 changes, 39 % of the variability in BMI changes, and 65 % of the variability in CFQ-R changes. ConclusionsThis study highlights a high level of heterogeneity in treatment response to ETI, which can only be partially explained by the baseline characteristics of the disease.

Relationship Between Lung Volumes and Heterogeneity in the Response to Elexacaftor/Tezacaftor/Ivacaftor in Patients With Cystic Fibrosis and Advanced Lung Disease

The effects of elexacaftor/tezacaftor/ivacaftor (ETI) on respiratory outcomes for people with cystic fibrosis (CF) were demonstrated by several clinical trials, mainly based on simple spirometry. However, gains in lung function may vary greatly between patients, and predictors of FEV1 change after treatment have yet to be defined. Which ventilatory parameters are involved in the heterogeneity of FEV1 change after 12-month ETI treatment in people with CF and advanced lung disease? This was a multicenter, observational, prospective cohort study at two major CF centers in Italy. We enrolled 47 adults with CF and advanced lung disease (FEV1< 40%or actively listed for lung transplant) who started ETI treatment between December 2019 and December 2021. At treatment initiation and after 12months, patients underwent body plethysmography. Values were compared at the two time points. To assess the relationship between baseline plethysmography measurements and treatment-induced changes in FEV1, we used the Spearman rank correlation coefficient (rs) and median quantile regressions. After 12months of ETI treatment, there was a significant increase in FEV1 %predicted from a median value of 36.0 (25th-75th percentile, 33-39) to 52 (25th-75th percentile, 43-61) (P< .001). Inspiratory capacity/total lung capacity (TLC) ratio also increased from 32.0 (25th-75th percentile, 28.6-36.9) to 36.3 (25th-75th percentile, 33.4-41.3) (P< .001). Specific airway resistance decreased from 263 (25th-75th percentile, 182-405) to 207 (25th-75th percentile, 120-258) (P< .001). Functional residual capacity/TLC ratio decreased from 68.2 (25th-75th percentile, 63.3-71.9) to 63.9 (25th-75th percentile, 58.8-67.1) (P< .001), and residual volume/TLC ratio decreased from 53.1 (25th-75th percentile, 48.3-59.4) to 45.6 (25th-75th percentile, 39.4-49.8) (P< .001). Changes in FEV1 %predicted negatively correlated with baseline functional residual capacity/TLC ratio (rs=-0.38, P= .009) and residual volume/TLC ratio (rs =-0.42, P= .004). After adjustment for age at treatment initiation and cystic fibrosis transmembrane conductance regulator genotype, we estimated that for each 10-unit increase in baseline residual volume/TLC ratio, the expected median change in FEV1 decreased by 2.3 (95%CI,-5.8 to-0.8). ETI was associated with improvements in both static and dynamic volumes in people with CF and advanced lung disease. Heterogeneity in FEV1 %predicted change after 12months of treatment may be predicted by the severity of hyperinflation at baseline.

The risk of severe acute pancreatitis depending on the genetic predisposition and diet

The aim of the study: to determine the influence of genetic predisposition and diet on the risk of severe acute pancreatitis (АР). Materials and methods. The results of diagnostics and treatment of 547 patients with acute pancreatitis were analyzed, 97 of them had a severe АР. Patients' blood DNA samples were used as research material. Detailed questionnaire on nutrition was carried out, the qualitative and quantitative composition of the food consumed was assessed. Genomic DNA was isolated using the standard PCE method. Genotyping was performed on a MALDI-TOF MassARRAY-4 analyzer. The role of the following polymorphic variants was studied: SPINK1 C&gt;T (rs6580502), PRSS1 C&gt;T (rs10273639), CFTR A&gt;G (rs213950), TNF -308 G&gt;A (rs1800629), IL1B A&gt;G (rs16944), IL5 A&gt;G (rs2069812), IL6 G&gt;C (rs1800795), IL10 T&gt;C (rs1800896), CETP G&gt;A (rs708272) and LPL T&gt;G (rs320). Statistical analysis was performed using SNPStats and Statistica 10.0 software. Results. In our study, we found that carriers of A/A rs2069812 IL5, G/G-G/C rs1800795 IL6 and T/T rs320 LPL genotypes increased the risk of severe acute pancreatitis. Alcohol abuse increases the risk of severe disease in carriers of T/T SPINK1 (rs6580502) and A/A CFTR (rs213950) genotypes. Constant exposure to alimentary risk factor manifested by increased consumption of fatty foods increases the risk in carriers of G/A-A/A rs 16944 IL1B, reduced protein and carbohydrate intake with food - in carriers of G/A-A/A rs2069812 IL5, carbohydrate - in carriers of G/A-A/A rs708272 CETP. Conclusion. Predictive diagnostics plays an important role in the prevention of severe acute pancreatitis, eliminating the effects of risk factors in carriers of genotypes associated with a severe course of the disease will make it possible to achieve positive success in the prevention of AP, to reduce the frequency of complications and the development of its severe course, to reduce mortality.

Multisite Verification of a Targeted CFTR Polymerase Chain Reaction/Capillary Electrophoresis Assay That Evaluates Pathogenic Variants Across Diverse Ethnic and Ancestral Groups.

Existing targeted cystic fibrosis screening assays miss important pathogenic CFTR variants in the ethnically diverse US population. To evaluate the analytic performance of a multiplex polymerase chain reaction (PCR)/capillary electrophoresis (CE) CFTR assay panel that simultaneously interrogates primary pathogenic variants of different ethnic/ancestral groups. Performance characteristic assessment and variant coverage comparison of the panel with a focus on ethnicity-specific CFTR variants were performed. Sample DNA was primarily from whole blood or cell lines. Detection of CFTR carriers was compared across several commercially available CFTR kits and recommended variant sets based on panel content. The panel interrogated 65 pathogenic CFTR variants representing 92% coverage from a recent genomic sequencing survey of the US population, including 4 variants with top 5 frequency in African or Asian populations not reflected in other targeted panels. In simulation studies, the panel represented 95% of carriers across the global population, resulting in a 6.9% to 19.0% higher carrier detection rate compared with 10 targeted panels or variant sets. Precision and sensitivity/specificity were 100% concordant. Multisite sample-level genotyping accuracy was 99.2%. Across PCR and CE instruments, sample-level genotyping accuracy was 97.1%, with greater than 99% agreement for all variant-level metrics. The CFTR assay achieves 92% or higher coverage of CFTR variants in diverse populations and provides improved pan-ethnic coverage of minority subgroups of the US populace. The assay can be completed within 5 hours from DNA sample to genotype, and performance data exceed acceptance criteria for analytic metrics. This assay panel content may help address gaps in ancestry-specific CFTR genotypes while providing a streamlined procedure with rapidly generated results.

Pathogenic Variants and Genotypes of the CFTR Gene in Russian Men with Cystic Fibrosis and CBAVD Syndrome.

Pathogenic CFTR variants cause cystic fibrosis (CF), and CF-related disorders (CF-RD), including bilateral aplasia of the vas deferens (CBAVD). The spectrum of clinical manifestations depends on the CFTR genotype. The frequency and spectrum of the CFTR variants vary between populations and clinical groups. CFTR variants and genotypes were analyzed in Russian men with CF (n = 546) and CBAVD syndrome (n = 125). Pathogenic variants were detected in 93.95% and 39.2% of the CF and CBAVD alleles, respectively. The most frequent c.1521_1523del (F508del; p.Phe508del) variant was found in 541 (49.5%) CF alleles. A total of 162 CFTR genotypes were revealed in CF patients, including 152 homozygous and 394 compound-heterozygous. The most common CF-genotype was F508del/F508del (24.9%). Other frequent CF-genotypes were F508del/3849+10kbC>T, F508del/CFTRdele2,3, and F508del/E92K. CF-causing variants and/or 5T allele were found in 88% of CBAVD patients: 5T/CFTRmut (48.0%), CFTRmut/N (17.6%), CFTRmut/CFTRmut (6.4%), 5T/5T (10.4%), 5T/N (5.6%) and N/N (12.0%), with the most common CBAVD-genotype being F508del/5T (29.6%). The allele frequencies of F508del, CFTRdele2,3 394delTT, and 3849+10kbC>T were significantly higher in CF patients. L138ins/L138ins, 2184insA/E92K, and L138ins/N genotypes were found in CBAVD, but not in CF patients. The results indicate certain differences in the frequency of some CFTR variants and genotypes in Russian CF and CBAVD patients.

Cystic fibrosis and pulmonary biofilms

Cystic fibrosis (CF) is an autosomal recessive disorder that involves the cystic fibrosis transmembrane conductance regulator. This protein is an anion channel that transfers chloride and bicarbonate from an intracellular location to an extracellular location. This transfer supports the formation of a normal periciliary fluid layer that is essential for ciliary function and the clearance of particulates from bronchi. Changes in mucociliary function can result in chronic bronchitis and recurrent infections. Studies using micro computed tomography of explanted lungs from CF patients have demonstrated that there is a significant reduction in the number of terminal bronchi and that approximately 50% of these bronchi are obstructed with secretions. These airways become colonized with bacteria, such as Pseudomonas aeruginosa, which can form biofilms, and this results in chronic inflammation and chronic airway damage. Biofilm formation can be predicted when mucoid colonies of pseudomonas grow out on routine bacterial cultures of sputum. Studies on the prognosis of patients with CF have demonstrated that there is lack of clear genotype-phenotype correlation, but one recent longitudinal study did report an association between more severe CFTR genotypes and clinical outcomes. In addition, the degree of pulmonary dysfunction and pseudomonas colonization, especially with drug resistant pseudomonas, predict poor outcomes. Bacteria in biofilms are more resistant to antibiotics, and the structure of biofilms limits host defense responses. Treatment approaches include the use of more than one antibiotic, the addition of inhaled antibiotics, the use of enzymes that degrade biofilms, and the use of small molecules that inhibit community metabolism in biofilms.&#x0D; &#x0D; Key words: cystic fibrosis transmembrane conductance regulator, extracellular secretions, periciliary fluid, Pseudomonas aeruginosa, biofilms

Intrahepatic Cholangiolitis in Cystic Fibrosis (ICCF): An Under-Appreciated Cause of Persistent Cholestasis in Infancy.

Liver histology in infants with cystic fibrosis (CF) and persistent cholestasis is seldom reported in detail. We extend previous observation of a distinctive intrahepatic cholangiopathy (ICCF) to 3 additional infants homozygous for CFTR pathological variants and a fourth infant with a heterozygous CFTR variant, summarizing our experience in 10 infants with CFTR variants and persistent cholestasis. Cholangiograms demonstrate abnormal extrahepatic ducts in 2 infants with CF, 1 with uniform dilatation interpreted as a choledochal cyst and the other with narrow patent ducts. Liver histology in 3 CF homozygotes had prominent ductular reaction with a focally destructive cholangiolitis (inflammation of small bile ducts). The CFTR heterozygote had generalized portal edema with ductular reaction and paucity but no cholangitis. Cholestasis slowly subsided in all infants. ICCF is characterized by severe ductular reaction, prominent cholangiocyte injury, and multifocal necrotizing cholangiolitis. Local aggregates of portal ceroid might suggest previous bile leakage from damaged ducts. ICCF in liver biopsies from infants with cystic fibrosis and persistent cholestasis is unrelated to the specific CFTR genotype. Liver biopsy findings and intraoperative cholangiogram help rule out biliary atresia. ICCF is an early manifestation of CF, a likely prototype for pathogenesis of cystic fibrosis liver disease later in life.

Theratyping of the Rare CFTR Genotype A559T in Rectal Organoids and Nasal Cells Reveals a Relevant Response to Elexacaftor (VX-445) and Tezacaftor (VX-661) Combination.

Despite the promising results of new CFTR targeting drugs designed for the recovery of F508del- and class III variants activity, none of them have been approved for individuals with selected rare mutations, because uncharacterized CFTR variants lack information associated with the ability of these compounds in recovering their molecular defects. Here we used both rectal organoids (colonoids) and primary nasal brushed cells (hNEC) derived from a CF patient homozygous for A559T (c.1675G>A) variant to evaluate the responsiveness of this pathogenic variant to available CFTR targeted drugs that include VX-770, VX-809, VX-661 and VX-661 combined with VX-445. A559T is a rare mutation, found in African-Americans people with CF (PwCF) with only 85 patients registered in the CFTR2 database. At present, there is no treatment approved by FDA (U.S. Food and Drug Administration) for this genotype. Short-circuit current (Isc) measurements indicate that A559T-CFTR presents a minimal function. The acute addition of VX-770 following CFTR activation by forskolin had no significant increment of baseline level of anion transport in both colonoids and nasal cells. However, the combined treatment, VX-661-VX-445, significantly increases the chloride secretion in A559T-colonoids monolayers and hNEC, reaching approximately 10% of WT-CFTR function. These results were confirmed by forskolin-induced swelling assay and by western blotting in rectal organoids. Overall, our data show a relevant response to VX-661-VX-445 in rectal organoids and hNEC with CFTR genotype A559T/A559T. This could provide a strong rationale for treating patients carrying this variant with VX-661-VX-445-VX-770 combination.

P019 Complex CFTR allele [HB1] L467F-F508del is responsible for poor clinical response to elexacaftor/tezacaftor/ivacaftor CFTRm therapy in a cystic fibrosis female with the L467F-F508del/621+1 G > Tgenotype: a case report

Introduction: Over 50% of Czech CF patients are currently treated with the CFTRm (elexacaftor/tezacaftor/ivacaftor; ETI) combination. Our case report confirms the dependence of the clinical benefit of CFTRm on the “complex” CFTR genotype and the important role of sweat chloride concentration (SCC) monitoring.

WS09.05 Aggregated genetic modifiers predict lung dysfunction at age 5–6 years in children with cystic fibrosis

Objectives: Non-CFTR genetic modifiers are implicated in lung disease of adults with CF. We recently demonstrated that in addition to CFTR genotype, non-CFTR genetic modifiers evaluated by a composite polygenic risk score (PRS) had a significant impact on development of early-onset lung disease in 1–3 yr-old children with CF. The objective of this study is to test the hypothesis that PRS also predicts lung function at age 5–6 yr.

Frequencies of pathogenic CFTR variants in Greek cystic fibrosis patients with allergic bronchopulmonary aspergillosis and Aspergillus fumigatus chronic colonization: A retrospective cohort study.

The clinical spectrum of Aspergillus fumigatus diseases in cystic fibrosis (CF) patients, including allergic bronchopulmonary aspergillosis (ABPA) and Aspergillus fumigatus chronic colonization, has recently gained attention due to its association with the progression of lung disease. Our aim was to examine whether there is a difference on pathogenic variant frequencies of the CFTR gene between CF patients with ABPA and those with A. fumigatus chronic colonization. Greek CF patients diagnosed with ABPA and/or A. fumigatus chronic colonization were grouped according to their CFTR genotype. Patients with "minimal" CFTR function were defined as carrying a combination of class I or II pathogenic variants, while patients with "residual" function as carrying at least one class III, IV, V or VI pathogenic variant. Fifty-four CF patients were included and all except one were defined as having "minimal" CFTR function. Among the 108 CFTR alleles, 69 (63.9%) of pathogenic variants belonged to class II, and 32 (29.6%) to class I. Five patients had a history of both ABPA and A. fumigatus chronic colonization. No significant difference was detected among patients diagnosed only with ABPA (n=29) and those who had only a positive history of A. fumigatus chronic colonization (n=20). The median age of ABPA diagnosis was significantly lower than the median age of A. fumigatus chronic colonization (P=0.011), while no significant difference was detected on median FEV1% predicted. No significant differences were detected in the type of CFTR pathogenic variants among patients with ABPA and those with A. fumigatus colonization. Similar studies should be performed in larger CF populations of different ethnic origin to further confirm our results.

Effects of prolonged proton pump inhibitor treatment on nutritional status and respiratory infection risk in cystic fibrosis: A matched cohort study.

Evidence on the effectiveness of proton pump inhibitors (PPI) as adjuvant therapy to improve maldigestion in people with cystic fibrosis (pwCF) is limited and there is increasing concern on possible side effects. We conducted a matched cohort study based on paediatric and adult pwCF who received PPI for ≥3 months. Treated patients were matched to a group of patients who never received PPI using a nearest neighbour propensity score matching based on sex, year of birth, CFTR genotype and pancreatic insufficiency. The study included 160 pwCF: 80 treated and 80 untreated patients. Over a median follow-up of 2 years, no significant differences in changes in BMI z-score were detected between groups (adjusted mean difference: 0.06, 95% CI: -0.17-0.30). At baseline 25% (n=20) of the treated patients and 22.5% (n=18) of the untreated patients had a positive culture for P. aeruginosa (Pa). At follow-up percentages of Pa positive cultures increased to 47.5% (n=38) in the treated group and to 26.3% (n=21) in the untreated group (adjusted mean difference: 23.1%, 95% CI: 10.8-35.3). Prolonged PPI therapy should be used cautiously in pwCF since it may increase the risk of respiratory infection by Pa. In addition, such treatment does not seem to improve nutritional status.

Characterization of CFTR mutations in people with cystic fibrosis and severe liver disease who are not eligible for CFTR modulators

Cystic-fibrosis-related liver disease (CFLD) is a variable phenotype of CF. The severe CFLD variant with cirrhosis or portal hypertension has a poor prognosis and life expectancy.CFTR modulator therapies are now available for people with CF and eligibility for such treatment is based on their CFTR genotype. We evaluated the genetic eligibility for elexacaftor, tezacaftor, ivacaftor (ETI), and ivacaftor (IVA) monotherapy in a previously reported CF cohort of 1591 people with CF of whom 171 with severe CFLD. Based on their CFTR mutations, 13% (N=184/1420) of subjects without CFLD and 11% (N=19/171) of those with severe CFLD are not eligible for either ETI or IVA therapy.The non-eligible patients without CFLD or with severe CFLD can currently not take advantage of the potential benefits of these new treatments. Although this study cannot provide any data regarding the effect of ETI or IVA on the progression of severe CFLD, the consequences for ineligibility of patients with extreme liver phenotype may be even more significant because of their poorer disease risk profile.

Influence of environmental factors and polymorphic loci rs6580502 of the SPINK1 gene, rs10273639 of the PRSS1 gene, rs213950 of the CFTR gene on the risk of developing acute alcoholic-alimentary pancreatitis

The study of genetic and environmental factors on the risk of acute alcoholic-alimentary pancreatitis (AАAР) is especially relevant to interpret individual links of pathogenesis, to reduce the incidence by eliminating the impact of harmful factors and improve the quality of life of the population through the introduction of optimal nutrition, and a healthy lifestyle, which is especially important for carriers of risk genotypes. The aim of the research was to study the influence of environmental factors and polymorphic loci rs6580502 of the SPINK1 gene, rs10273639 of the PRSS1 gene, rs213950 of the CFTR gene on the risk of АAР. Material and methods. Blood DNA samples obtained from 547 patients with AАAР and 573 healthy individuals were used as the material for the study. The groups were comparable by sex and age. All participants were assessed qualitatively and quantitatively for risk factors, smoking and alcohol consumption, the frequency, quantity and regularity of intake of various types of foods, as well as the size and number of portions eaten. Genomic DNA was isolated by the standard phenol-chloroform extraction method, multiplex genotyping of SNPs was performed on a MALDI-TOF MassARRAY-4 genetic analyzer. Results. It was found that the T/T genotype (p=0.0012) of the rs6580502 SPINK1 was associated with an increased risk of AAAP, and the T allele (p=0.0001) and C/T and T/T genotypes (p=0.0001) of the rs10273639 PRSS1, A allele (p=0.01) and A/G and A/A genotypes (p=0.0006) of the rs213950 CFTR were associated with an decreased risk of the disease. The revealed effects of polymorphic loci of candidate genes were enhanced by the effect of alcohol consumption. The risk of AAAP was reduced by fat intake of less than 89 g per day in carriers of the A/G-A/A CFTR genotypes (rs213950), consumption of fresh vegetables and fruits of more than 27 g per day in carriers of the T/C-T/T PRSS1 genotypes (rs10273639), protein intake of more 84 g per day in carriers of T/C-T/T PRSS1 rs10273639 and A/G-A/A CFTR rs213950. The most significant models of gene-environment interactions included risk factors: deficiency in the diet of protein, fresh vegetables and fruits, smoking, and polymorphic variants of the PRSS1 (rs10273639) and SPINK (rs6580502) genes. Conclusion. In order to prevent the development of AAAP, carriers of risk genotypes of candidate genes need not only to exclude or significantly reduce alcohol consumption (in terms of volume, frequency and duration); but also carriers of the A/G-A/A CFTR genotypes (rs213950) need to balance the diet by reducing fat intake to less than 89 g per day and increasing protein intake to more than 84 g per day; carriers of the T/C-T/T PRSS1 (rs10273639) genotypes should increase their intake of fresh vegetables and fruits over 27 g/day and protein over 84 g/day.