Diagnostic Transitions of Cystic Fibrosis and CRMS Compared After 12 Years of Newborn Screening in California.

OBJECTIVE: To compare the long-term diagnostic transitions for cystic fibrosis (CF) and cystic fibrosis transmembrane conductance regulator (CFTR)- related metabolic syndrome (CRMS) side-by-side since the onset of newborn screening in California. STUDY DESIGN: Using real-world data, we conducted a retrospective cohort study to compare long-term observations of CRMS and CF in California and the diagnostic transitions from one to the other using clinical and diagnostic metrics. The California Genetic Disease Screening Program newborn screening for CF employs an immunoreactive trypsinogen tier-1 laboratory test, followed by molecular testing. This approach captures CF and CRMS, a diagnosis of "watchful waiting" among infants at risk for CF but with signs and symptoms that may emerge outside the screening window. Waiting entails periodic diagnostic reviews that can continue for many years; the California Genetic Disease Screening Program routinely conducts 5 years of follow-up for each child identified with a disorder. We used categorial logistic regression to compare the transitions with CRMS. RESULTS: After screening 5 944 700 newborns between July 2007 and July 2019, 694 CF cases and 1257 CRMS cases were identified. Of the 1257 CRMS cases, 66 (5.2%, 95% CI 3.9%-6.4%) transitioned from CRMS to CF (CRMS2CF) at a mean age of 3.3 years (median = 2.9 years). CRMS2CF cases had longer follow-up periods and were more likely later to develop positive sweat chloride and fecal elastase test results after 6 months of life than other CRMS cases. CONCLUSIONS: These results suggest that children who have a CRMS2CF transition are more likely to develop positive biochemical markers than other patients who are diagnosed as CRMS and have few clinical indications during the first 5 years of follow-up.

Literary evidence of the impact of nonbiological risk factors on CRMS/CFSPID: A scoping review.

Newborn screening for cystic fibrosis (CF) occasionally results in an inconclusive diagnosis of this disease, and these individuals are designated as CFTR-related metabolic syndrome (CRMS) in the United States, and CF Screen Positive Inconclusive Diagnosis (CFSPID) in other countries. Some of these asymptomatic individuals will progress to symptomatic disease, but risk factors associated with disease progression are not well understood. This scoping review was conducted to comprehensively map nonbiological risk factors in the CRMS/CFSPID literature and to identify understudied topics. Six electronic databases were systematically searched, resulting in 2951 studies. Forty nine eligible works were identified as including information on nonbiological risk factors related to CRMS/CFPSID. Eligible studies were published from 2002 to 2024, most prevalently in the United States (36.7%), and as quantitative data (81.6%). Of the 49 eligible works, 23 articles contributed only intellectual conjecture, while 26 articles contained original data, which underwent full-text qualitative content analysis. Key themes identified in descending order of content coverage included Psychological Impact, Management Care, Newborn Screening and Diagnostics, Communicating Diagnosis, and Lifestyle and External Exposures. This scoping review identified that while nonbiological risk factors are being studied in the CRMS/CFSPID literature, there was nearly equal distribution of works gathering original data to those citing previously published information. These findings indicate a critical need for original data collection on these risk factors, particularly on understudied topics identified herein.

International Perspectives of Extended Genetic Sequencing When Used as Part of Newborn Screening to Identify Cystic Fibrosis.

There is increasing interest in using extended genetic sequencing (EGS) in newborn screening (NBS) for cystic fibrosis (CF). How this is implemented will change the number of children being given an uncertain outcome of CRMS/CFSPID (cystic fibrosis transmembrane conductance regulator (CFTR)-related metabolic syndrome/CF Screen Positive Inconclusive Diagnosis), probable carrier results, and the number of missed CF diagnoses. An international survey of CF health professionals was used to gather views on two approaches to EGS-specific (may reduce detection of CRMS/CFSID but miss some CF cases) versus sensitive (may increase detection of CRMS/CFSPID but avoid missing more CF cases). Health professionals acknowledged the anxiety caused to parents (and health professionals) from the uncertainty surrounding the prognosis and management of CRMS/CFSPID. However, most preferred the sensitive approach, as overall, identifying more cases of CRMS/CFSPID was viewed as less physically and psychologically damaging than a missed case of CF. The importance of early diagnosis and treatment for CF to ensure better health outcomes and reducing diagnostic odysseys for parents were highlighted. A potential benefit to identifying more children with CRMS/CFSPID included increasing knowledge to obtain a better understanding of how these children should best be managed in the future.

ECFS standards of care on CFTR-related disorders: Towards a comprehensive program for affected individuals.

After three publications defining an updated guidance on the diagnostic criteria for people with cystic fibrosis transmembrane conductance regulator (CFTR)-related disorders (pwCFTR-RDs), establishing its relationship to CFTR-dysfunction and describing the individual disorders, this fourth and last paper in the series addresses some critical challenges facing health care providers and pwCFTR-RD. Topics included are: 1) benefits and obstacles to collect data from pwCFTR-RD are discussed, together with the opportunity to integrate them into established CF-registries; 2) the potential of infants designated CRMS/CFSPID to develop a CFTR-RD and how to communicate this information; 3) a description of the challenges in genetic counseling, with particular regard to phenotypic variability, unknown long-term evolution, CFTR testing and pregnancy termination 4) a proposal for the assessment of potential barriers to the implementation and dissemination of the produced documents to health care professionals involved in the care of pwCFTR-RD and a process to monitor the implementation of the CFTR-RD recommendations; 5) clinical trials investigating the efficacy of CFTR modulators in CFTR-RD and how endpoints and outcomes might be adapted to the heterogeneity of these disorders.

Stakeholder Views of the Proposed Introduction of Next Generation Sequencing into the Cystic Fibrosis Screening Protocol in England.

The project aimed to gather, analyse, and compare the views of stakeholders about the proposed UK cystic fibrosis (CF) screening protocol incorporating next generation sequencing (NGS). The study design was based on principles of Q-methodology with a willingness-to-pay exercise. Participants were recruited from 12 CF centres in the UK. The study contained twenty-eight adults who have experience with CF (parents of children with CF (n = 21), including parents of children with CF transmembrane conductance regulator (CFTR)-related metabolic syndrome (CRMS)/CF screen positive-inconclusive diagnosis (CFSPID), an uncertain outcome (n = 3), and adults with CF (n = 4)), and nine health professionals involved in caring for children with CF. Parents and health professionals expressed a preference for a sensitive approach to NGS. This was influenced by the importance participants placed on not missing any children with CF via screening and the balance of harm between missing a case of CF compared to picking up more children with an uncertain outcome (CRMS/CFSPID). Given the preference for a sensitive approach, the need for adequate explanations about potential outcomes including uncertainty (CFSPID) at the time of screening was emphasized. More research is needed to inform definitive guidelines for managing children with an uncertain outcome following CF screening.

Biochemical and genetic tools to predict the progression to Cystic Fibrosis in CRMS/CFSPID subjects: A systematic review.

OBJECTIVES: Aim of this study was to identify risk factors for a progression to cystic fibrosis (CF) in individuals detected as CF Screening Positive, Inconclusive Diagnosis (CFSPID). METHODS: This is a systematic review through literature databases (2015-2023). Blood immunoreactive trypsinogen (b-IRT) values, CFTR genotype, sweat chloride (SC) values, isolation of Pseudomonas aeruginosa (Pa) from respiratory samples, Lung Clearance Index (LCI) values in CFSPIDs who converted to CF (CFSPID > CF) and age at CF transition were assessed. RESULTS: Percentage of CFSPID > CF varies from 5.3 % to 44 %. Presence of one CF-causing CFTR variant in trans with a variant with variable clinical consequences (VVCC), an initial SC ≥ 40 mmol/L, an increase of SC > 2.5 mmol/L/year and recurrent isolation of pseudomonas aeruginosa (Pa) from airway samples could allow identification of subjects at risk of progression to CF. CONCLUSIONS: CFSPIDs with CF causing variant/VVCC genotype and first SC in the higher borderline range may require more frequent and prolonged clinical follow-up.

The Psychological Impact on Parents of Children who Receive an Inconclusive Diagnosis for Cystic Fibrosis following Newborn Screening: A Systematic Mini-Review.

Newborn screening (NBS) has been available for the diagnosis of cystic fibrosis (CF) over the last decades. Through the implementation of NBS, a new designation emerged, that of CF related metabolic syndrome (CRMS) or cystic fibrosis screen positive inconclusive diagnosis (CFSPID). As there is uncertainty regarding the clinical progression of these infants to CF, some studies have investigated the psychological impact of CRMS/CFSPID on their parents. This systematic narrative review aimed to describe the findings of the relevant studies. The number of studies is limited and the study samples are relatively small. It seems that there is a negative impact of CRMS/CFSPID on parental mental health. While some studies indicated similar levels of parental anxiety among those with infants diagnosed with CF and those with CRMS/CFSPID, not all studies reached the same conclusion. Parental uncertainty represents another mental dimension of the impact associated with the designation of CRMS/CFSPID. These observations suggest that parents of infants with CRMS/CFSPID should be provided with effective communication, and it may also be beneficial to consider parental mental screening. More robust and long-term studies are required to detect differences in parental emotional status between those with infants diagnosed with CF and those with CRMS/CFSPID.

Standards for the care of people with cystic fibrosis (CF): A timely and accurate diagnosis.

There is considerable activity with respect to diagnosis in the field of cystic fibrosis (CF). This relates primarily to developments in newborn bloodspot screening (NBS), more extensive gene analysis and improved characterisation of CFTR-related disorder (CFTR-RD). This is particularly pertinent with respect to accessibility to variant-specific therapy (VST), a transformational intervention for people with CF with eligible CFTR gene variants. This advance reinforces the need for a timely and accurate diagnosis. In the future, there is potential for trials to assess effectiveness of variant-specific therapy for CFTR-RD. The guidance in this paper reaffirms previous standards, clarifies a number of issues, and integrates emerging evidence. Timely and accurate diagnosis has never been more important for people with CF.

Children with cystic fibrosis are still receiving inconclusive diagnosis despite undergoing newborn screening.

AIM: We aimed to familiarise clinicians with the terms cystic fibrosis transmembrane conductance regulator related metabolic syndrome (CRMS) and cystic fibrosis screen positive inconclusive diagnosis (CFSPID). We also sought to highlight the monitoring and outcomes of children that match these designations. METHODS: A literature review was performed by searching PubMed from its inception until 30 November 2022. All relevant articles were included in this narrative review. RESULTS: Despite the implementation of newborn screening programmes for cystic fibrosis (CF), the diagnosis remains uncertain in some newborn infants with elevated immunoreactive trypsinogen. In 2016, a unified definition for CRMS/CFSPID was established to categorise these children. While many of them remain healthy, a portion of these children may develop CF. As a result, it is crucial to monitor them regularly. CONCLUSION: CRMS/CFSPID is a designation and not a diagnosis. Longer longitudinal studies are needed to shed light on the most appropriate follow-up of these children. Paediatricians need to be knowledgeable about this condition in order to administer proper care, and children should be in contact with their local CF centre.

Comparison between Gibson-Cooke and Macroduct Methods in the Cystic Fibrosis Neonatal Screening Program and in Subjects Who Are Cystic Fibrosis Screen-Positive with an Inconclusive Diagnosis.

The sweat test (ST) is the current diagnostic gold standard for cystic fibrosis (CF). Many CF centres have switched from the Gibson-Cooke method to the Macroduct system-based method. We used these methods simultaneously to compare CF screening outcomes. STs using both methods were performed simultaneously between March and December 2022 at CF Centre in Florence. We included newborns who underwent newborn bloodspot screening (NBS), newborns undergoing transfusion immediately after birth, and children with CF screen-positive, inconclusive diagnosis (CFSPID). We assessed 72 subjects (median age 4.4 months; range 0-76.7): 30 (41.7%) NBS-positive, 18 (25.0%) newborns who underwent transfusion, and 24 (33.3%) children with CFSPID. No significant differences were found between valid sample numbers, by patient ages and groups (p = 0.10) and between chloride concentrations (p = 0.13), except for sweat chloride (SC) measured by the Gibson-Cooke and Macroduct methods in CFSPID group (29.0, IQR: 20.0-48.0 and 22.5, IQR: 15.5-30.8, respectively; p = 0.01). The Macroduct and Gibson-Cooke methods showed substantial agreement with the SC values, except for CFSPID, whose result may depend on the method of sweat collection. In case of invalid values with Macroduct, the test should be repeated with Gibson-Cooke method.

Cystic fibrosis to CFSPID: Burden of care vs need and rational approach to weaning therapies.

We present a case of a 10-year-old boy initially diagnosed with CF based on NBS guidelines. However, as CF genetics knowledge has advanced, he has been reclassified as CFSPID based on normal investigations and excellent general clinical status, in line with updated CFSPID guidelines. This case highlights the significance of reviewing CF diagnoses according to the latest understanding of CFTR mutation phenotypes, as well as the patient's clinical status. In order to identify opportunities to save patients from burdensome CF treatment and management, we review current CFSPID guidelines, emphasizing care tailored to each individual case.

Cystic Fibrosis screen positive, inconclusive diagnosis (CFSPID) to Cystic Fibrosis: Detecting disease with serial assessments.

We present the case of a child given a CFSPID designation in early life who was later reclassified as having CF based on a combination of recurrent respiratory symptoms and CFTR functional testing, despite normal sweat chloride levels. Here we demonstrate the importance of monitoring these children, each time reviewing the diagnosis based on updated understanding of individual CFTR mutation phenotypes or clinical findings inconsistent with the designation. This case identifies situations in which the CFSPID designation should be challenged, and gives an approach for this when CF is suspected.

Clinical Consequences and Functional Impact of the Rare S737F CFTR Variant and Its Responsiveness to CFTR Modulators.

S737F is a Cystic Fibrosis (CF) transmembrane conductance regulator (CFTR) missense variant. The aim of our study was to describe the clinical features of a cohort of individuals carrying this variant. In parallel, by exploiting ex vivo functional and molecular analyses on nasal epithelia derived from a subset of S737F carriers, we evaluated its functional impact on CFTR protein as well as its responsiveness to CFTR modulators. We retrospectively collected clinical data of all individuals bearing at least one S737F CFTR variant and followed at the CF Centre of Tuscany region (Italy). Nasal brushing was performed in cooperating individuals. At study end clinical data were available for 10 subjects (mean age: 14 years; range 1-44 years; 3 adult individuals). Five asymptomatic subjects had CF, 2 were CRMS/CFSPID and 3 had an inconclusive diagnosis. Ex vivo analysis on nasal epithelia demonstrated different levels of CF activity. In particular, epithelia derived from asymptomatic CF subjects and from one of the subjects with inconclusive diagnosis showed reduced CFTR activity that could be rescued by treatment with CFTR modulators. On the contrary, in the epithelia derived from the other two individuals with an inconclusive diagnosis, the CFTR-mediated current was similar to that observed in epithelia derived from healthy donors. In vitro functional and biochemical analysis on S737F-CFTR expressed in immortalized bronchial cells highlighted a modest impairment of the channel activity, that was improved by treatment with ivacaftor alone or in combination with tezacaftor/elexacaftor. Our study provide evidence towards the evaluation of CFTR function on ex vivo nasal epithelial cell models as a new assay to help clinicians to classify individuals, in presence of discordance between clinical picture, sweat test and genetic profile.

Outcomes of children with cystic fibrosis screen positive, inconclusive diagnosis/CFTR related metabolic syndrome.

Background: Some infants undergoing newborn screening (NBS) tests have inconclusive sweat chloride test (SCT) results that lead to the designation of Cystic Fibrosis Screen Positive, Inconclusive Diagnosis/CFTR-related metabolic syndrome (CFSPID/CRMS). Some proportion of them transition to a CF diagnosis, but no predictive markers can stratify which are at risk for this transition. We report single-center outcomes of children with CRMS. Methods: We retrospectively identified all infants born in Alabama from 2008 through 2020 referred to our CF Center with an elevated immunoreactive trypsinogen level (IRT) associated with a cystic fibrosis transmembrane conductance regulator (CFTR) mutation (IRT+/DNA+) who had at least one SCT result documented. Infants were classified per established guidelines as Carrier, CRMS, or CF based on the IRT+/DNA+ and SCT results. The electronic health record was reviewed for follow-up visits until the children received a definitive diagnosis (to carrier or CF) according to current diagnostic guidelines for CF, or through the end of the 2020 year. Results: Of the 1,346 infants with IRT+ and at least 1 CFTR mutation identified (IRT+/DNA+), 63 (4.7%) were designated as CRMS. Of these infants, 12 (19.1%) transitioned to Carrier status (CRMS-Carrier), 40 (63.5%) of them remained CRMS status (CRMS-Persistent) and 11 (17.5%) of them transitioned to a diagnosis of CF (CRMS-CF). Of the 11 children in the CRMS-CF group, 4 (36%) had an initial SCT 30-39 mmol/L, 4 (36%) had an initial SCT 40-49 mmol/L and 3 (27%) had an initial SCT 50-59 mmol/L. These children also had higher initial sweat tests and greater yearly increases in sweat chloride values than others with CRMS. We found that in comparison to children in the CRMS-P group, a greater proportion of children in the CRMS-CF group cultured bacteria like methicillin-resistant Staphylococcus aureus, Stenotrophomonas maltophilia, and Pseudomonas aeruginosa, had smaller weight-for-height percentiles and remained smaller over time despite slightly greater growth. Conclusion: Infants with an inconclusive diagnosis of CF should continue to receive annual care and management given their potential risk of transition to CF. Further research is needed to assess whether certain phenotypic patterns, clinical symptoms, diagnostic tests or biomarkers could better stratify these children.

A Multicentre Italian Study on the Psychological Impact of an Inconclusive Cystic Fibrosis Diagnosis after Positive Neonatal Screening.

BACKGROUND: An inconclusive diagnosis of cystic fibrosis (CF) after positive newborn screening (NBS) may cause parental distress. We compared the psychological impact of CF transmembrane conductance regulator-related metabolic syndrome (CRMS)/CF screen-positive, inconclusive diagnosis (CFSPID), and clear CF diagnosis, on parents. METHODS: The participants were administered the Generalized Anxiety Disorder Scale, Patient Health Questionnaire-9, and the Italian version of the Impact of Event Scale-Revised as quantitative tools and semi-structured interviews as qualitative tools. Parental experience, child representation, relationships, future information, and perception of health status were investigated. Interviews were recorded and transcribed verbatim maintaining anonymity. RESULTS: Thirty-two families were enrolled: sixteen with CF and CRMS/CFSPID, respectively. Anxiety and depression values were high in both groups, as were the measurement of traumatic impact subscales: avoidance, intrusiveness, and hyperarousal. The children's health was evaluated by respective parents as being nearly healthy. CONCLUSIONS: Our results highlight negative psychological impacts, including emotional and affective representations, on parents of children with inconclusive CF diagnosis compared with those with clear diagnosis.

European survey of newborn bloodspot screening for CF: opportunity to address challenges and improve performance.

BACKGROUND: The aim of this study was to record the current status of newborn bloodspot screening (NBS) for CF across Europe and assess performance. METHODS: Survey of representatives of NBS for CF programmes across Europe. Performance was assessed through a framework developed in a previous exercise. RESULTS: In 2022, we identified 22 national and 34 regional programmes in Europe. Barriers to establishing NBS included cost and political inertia. Performance was assessed from 2019 data reported by 21 national and 21 regional programmes. All programmes employed different protocols, with IRT-DNA the most common strategy. Six national and 11 regional programmes did not use DNA analysis. CONCLUSIONS: Integrating DNA analysis into the NBS protocol improves PPV, but at the expense of increased carrier and CFSPID recognition. Some programmes employ strategies to mitigate these outcomes. Programmes should constantly strive to improve performance but large datasets are needed to assess outcomes reliably.

Detection of disease-causing CFTR variants in state newborn screening programs.

BACKGROUND: Newborn screening (NBS) algorithms for cystic fibrosis (CF) vary in the United State of America and include different cystic fibrosis transmembrane conductance regulator (CFTR) variants. CFTR variant distribution varies among racial and ethnic groups. OBJECTIVE: Our objectives were to identify differences in detection rate by race and ethnicity for CFTR variant panels, identify each US state detection rate for CFTR variant panels, and describe the rate of false-negative NBS and delayed diagnoses by race and ethnicity. METHODS: This is a cross-sectional analysis of the detection rate of at least 1 CFTR variant for seven panels by race and ethnicity in genotyped people with CF (PwCF) or CFTR-related metabolic syndrome (CRMS)/CFTR-related disorders in CF Foundation Patient Registry (CFFPR) in 2020. We estimated the case detection rate of CFTR variant panels by applying the detection rate to Census data. Using data from CFFPR, we compared the rate of delayed diagnosis or false-negative NBS by race and ethnicity. RESULTS: For all panels, detection of at least 1 CFTR variant was highest in non-Hispanic White PwCF (87.5%-97.0%), and lowest in Black, Asian, and Hispanic PwCF (41.9%-93.1%). Detection of at least 1 CFTR variant was lowest in Black and Asian people with CRMS/CFTR-related disorders (48.4%-64.8%). States with increased racial and ethnic diversity have lower detection rates for all panels. Overall, 3.8% PwCF had a false-negative NBS and 11.8% had a delayed diagnosis; Black, Hispanic, and mixed-race PwCF were overrepresented. CONCLUSION: CFTR variant panels have lower detection rates in minoritized racial and ethnic groups leading to false-negative NBS, delayed diagnosis, and likely health disparities.

Non-pulmonary CFTR-related symptom improvement with ivacaftor in p.Phe508del/p.Arg117His (7T) cystic fibrosis.

Diagnosis and management of CRMS/CFSPID and cystic fibrosis (CF) with mild phenotypes remains challenging, and this extends to expanding practice with the use of CFTR modulators. We describe a case of an 18-year-old man with p.F508del/p.Arg117His(7T) initially presenting with CRMS/CFSPID. He went on to be diagnosed with pancreatic sufficient CF with minimal lung disease. However, he has had significant CFTR-related symptoms with recurrent pancreatitis and chronic sinusitis. These non-pulmonary symptoms resolved following introduction of the CFTR modulator ivacaftor. Care for those with mild CF phenotypes, CRMS/CFSPID and those with CFTR-RD must be individualized, and open dialogue, education and patient centred care is necessary to ascertaining which patients might benefit from management in a multidisciplinary CF clinic and treatment. There may be a role for expanding the use of CFTR modulators to include non-pulmonary manifestations of CFTR dysfunction in some cases.

Different management approaches and outcome for infants with an inconclusive diagnosis following newborn screening for cystic fibrosis (CRMS/CFSPID) and Pseudomonas aeruginosa isolation.

INTRODUCTION: Evidence is currently lacking to guide the management of cystic fibrosis (CF) transmembrane conductance regulator-related metabolic syndrome CF screen-positive inconclusive diagnosis (CRMS/CFSPID) with Pseudomonas aeruginosa (Pa)-positive respiratory culture. This study assessed the clinical data, management, and outcomes of an Italian cohort of CRMS/CFSPID infants with Pa isolated from their airways. METHODS: Data of Pa-positive CRMS/CFSPID infants born between January 2011 and August 2018 and followed at five CF Italian centres were retrospectively extracted. Further data were collected until June 2021 to assess outcomes, prevalence of subjects treated with antimicrobials, and treatment type and duration. RESULTS: Forty-three asymptomatic CRMS/CFSPID patients (median age on 30 June 2021, 82 months; interquartile range [IQR], 63-98 months) with at least one positive airway culture for non-mucoid Pa (median age at first isolation, 18.7 months; IQR, 7-25 months) were enrolled. Of them, 24 (55.8%) underwent anti-Pa therapy. Pa clearance occurred in 22 (91.6%) of 24 patients versus spontaneous clearance in 16 of 19 (84.2%) untreated patients (chi-square, 0.5737; p = 0.44878). After a median follow-up of 6.2 years (IQR, 3.0-9.9), 7 (16.3%) were diagnosed with CF after a pathological sweat test (median age, 43 months; IQR, 28-77 months), 3 (7%) developed recurrent pancreatitis or isolated bronchiectasis consistent with CFTR-related disorder, and the CRMS/CFSPID classification remained in 33 (76.7%). CONCLUSIONS: Pa detection frequently occurs in asymptomatic infants with CRMS/CFSPID but tends to clear spontaneously. More studies are needed to determine if Pa isolation can predict evolution.