Practice variation of genetic counselor engagement in the cystic fibrosis newborn screen-positive diagnostic resolution process

Cystic fibrosis foundation position paper: Redefining the cystic fibrosis care team

Interdisciplinary teams care for people with cystic fibrosis (pwCF) at specialized treatment centers. These teams have laid the foundation for the cystic fibrosis (CF) care model responsible for gains in health outcomes and quality of life within the CF community. However, the landscape of CF care is transforming, invigorated by new technologies, accessibility of cystic fibrosis transmembrane conductance regulator (CFTR) therapies, and increased utilization of telemedicine. In light of these advances, it is appropriate to re-evaluate the CF care team structure. This position paper offers guidance for the structure of a CF care center designed to meet the evolving needs of the CF community. Fundamental to the proposed center structure is recognition of pwCF and their families as integral members of their care teams, underpinning the necessity for shared decision making, awareness of social determinants of health, and active partnership between all healthcare professionals involved in the care of pwCF.

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.

Genetic counseling access and service delivery in New York State is variable for parents of infants with complex CFTR genotypes conferring uncertain phenotypes

BACKGROUND

New York State (NYS) utilizes a three-tiered cystic fibrosis newborn screening (CFNBS) algorithm that includes cystic fibrosis transmembrane conductance regulator (CFTR) gene sequencing. Infants with >1 CFTR variant of potential clinical relevance, including variants of uncertain significance or varying clinical consequence are referred for diagnostic evaluation at NYS cystic fibrosis (CF) Specialty Care Centers (SCCs).

AIMS

As part of ongoing quality improvement efforts, demographic, screening, diagnostic, and clinical data were evaluated for 289 CFNBS-positive infants identified in NYS between December 2017 and November 2020 who did not meet diagnostic criteria for CF and were classified as either: CFTR-related metabolic syndrome/CF screen positive, inconclusive diagnosis (CRMS/CFSPID) or CF carriers.

RESULTS

Overall, 194/289 (67.1%) had CFTR phasing to confirm whether the infant's CFTR variants were in cis or in trans. Eighteen complex alleles were identified in cis; known haplotypes (p.R117H+5T, p.F508del+p.L467F, and p.R74W+p.D1270N) were the most common identified. Thirty-two infants (16.5%) with all variants in cis were reclassified as CF carriers rather than CRMS/CFSPID. Among 263 infants evaluated at an NYS SCC, 70.3% were reported as having received genetic counseling about their results by any provider, with 96/263 (36.5%) counseled by a certified genetic counselor.

CONCLUSION

Given the particularly complex genetic interpretation of results generated by CFNBS algorithms including sequencing analysis, additional efforts are needed to ensure families of infants with a positive CFNBS result have CFTR phasing when needed to distinguish carriers from infants with CRMS/CFSPID, and access to genetic counseling to address implications of CFNBS results.

Experiences of cystic fibrosis newborn screening and genetic counseling

The South Carolina cystic fibrosis (CF) newborn screening (NBS) program changed in 2019 to include CFTR genotyping for babies with top 4% immunoreactive trypsinogen, which improves sensitivity and timeliness but increases carrier detection. Carrier identification has genetic implications for the family and parents of NBS+ babies have increased emotional distress. Genetic counseling (GC) may increase parent understanding and reduce anxiety yet is not uniformly offered at CF centers. We report our early results after implementing GC for NBS+ families at the time of sweat chloride testing based on GC availability, which resulted in an unselected GC- control arm. Sixteen mothers (GC+ = 9, GC- = 7) participated in an online survey about their experience. Responses were analyzed in aggregate and for differences between GC+ and GC- groups. All-respondent sadness and anxiety increased with notification of the NBS+ result and decreased after sweat test results. Anxiety and sadness were greater in GC- compared to GC+ until after the diagnosis was resolved, though emotional differences between the groups were not statistically significant. On a scale of 0 = not at all to 10 = extremely, GC was rated very helpful (mean 9.0, range 5-10), informative (mean 8.9, range 4-10), comforting (mean 9.1, range 6-10), and minimally distracting (mean 1.8, range 0-9). All participants correctly identified that a risk for a child to have CF exists when both parents are (at least) carriers. Delivery of NBS results to respondents varied by timing, informant, and information given. The child's pediatrician notified 10 (62.5%) of the NBS+ result. Parents felt they were notified in a timely manner (68.8%), by someone knowledgeable about NBS (62.5%), the sweat test (62.5%), CF (43.8%), and genetics (43.8%) and who cared about them (81.3%). Parents felt worried (81.3%), confused (81.3%), empowered (25%), and other (sad, shocked, scared, overwhelmed, devastated, defeated). Data from this single-center study suggest benefit of GC, that families would value earlier contact with an expert, and that prompt diagnostic resolution may reduce duration of parental distress.

Diagnostic and Communication Challenges in Cystic Fibrosis Newborn Screening

As of December 2009, cystic fibrosis (CF) newborn screening (NBS) is performed in all 50 US states and the District of Columbia. Widespread implementation of CF newborn screening (CFNBS) in the US and internationally has brought about new and varied challenges. Immunoreactive trypsinogen (IRT) remains the first, albeit imperfect, biomarker used universally in the screening process. Advances in genetic testing have provided an opportunity for newborn screening programs to add CFTR sequencing tiers to their algorithms. This in turn will enable earlier identification of babies with CF and improve longer-term outcomes through prompt treatment and intervention. CFTR sequencing has led to the ability to identify infants with CF from diverse ethnic and racial backgrounds more equitably while also identifying an increasing proportion of infants with inconclusive diagnoses. Using the evolution of the New York State CF newborn screening program as a guide, this review outlines the basic steps in a universal CF newborn screening program, considers how to reduce bias, highlights challenges, offers guidance to address these challenges and provides recommendations for future consideration.

Genetic counseling access for parents of newborns who screen positive for cystic fibrosis: Consensus guidelines

INTRODUCTION

A risk associated with cystic fibrosis newborn screening (CFNBS) is parental misunderstanding of genetic information generated by the over 6600 positive screens reported annually in the United States. CFNBS algorithms incorporating DNA analysis can generate genetic information that requires clinical interpretation and has significance for the newborn, parents, and other relatives. Engagement between CF care centers and trained genetic counseling providers, such as licensed and/or certified genetic counselors (GCs), is variable and limited in providing information to CFNBS positive (CFNBS+) families.

METHODS

Using a modified Delphi process, a workgroup of CFNBS experts developed recommendation statements for engagement of genetic counseling services in CF care centers where CFNBS + diagnostic evaluations are performed. Statements were assessed over three rounds of surveys, one face-to-face meeting, and through public feedback.

RESULTS

Seventeen statements achieved >80% consensus (range: 82%-100%). The workgroup affirmed prior CFF policy statements recommending genetic counseling for parents of infants with CFNBS+. The remaining statements addressed infrastructure and logistics of genetic counseling services, including defining appropriate training for genetic counseling providers and counseling content, establishing a path to equal access to genetic counseling providers across CF care centers, and setting a standard for client-centered CFNBS genetic counseling that is respectful of diverse patient needs and autonomy.

CONCLUSIONS

Implementation of client-centered genetic counseling for CFNBS+ families in CF care centers by providers with expertise in both CF and genetic counseling will require efforts to further define core concepts, enhance the education of providers, and develop opportunities for access via telemedicine.

Challenging the dogma of the healthy heterozygote: Implications for newborn screening policies and practices

Heterozygous (carrier) status for an autosomal recessive condition is traditionally considered to lack significance for an individual's health, but this assumption has been challenged by a growing body of evidence. Carriers of several autosomal recessive disorders and some X-linked diseases are potentially at risk for the pathology manifest in homozygotes. This minireview provides an overview of the literature regarding health risks to carriers of two common autosomal recessive conditions on the Recommended Uniform Screening Panel: sickle cell disease [sickle cell trait (SCT)] and cystic fibrosis (CF). We also consider and comment on bioethical and policy implications for newborn blood screening (NBS). Health risks for heterozygotes, while relatively low for individuals, are often influenced by intrinsic (e.g., other genomic variants or co-morbidities) and extrinsic (environmental) factors, which present opportunities for personalized genomic medicine and risk counseling. They create a special challenge, however, for developing screening/follow-up policies and for genetic counseling, particularly after identification and reporting of heterozygote status through NBS. Although more research is needed, this minireview of the SCT and CF literature to date leads us to propose that blanket terms such as "healthy heterozygotes" or "unaffected carriers" should be superseded in communications about NBS results, in favor of a more nuanced paradigm of setting expectations for health outcomes with "genotype-to-risk." In the molecular era of NBS, it remains clear that public health needs to become better prepared for the full range of applied genetics.

CRMS/CFSPID Subjects Carrying D1152H CFTR Variant: Can the Second Variant Be a Predictor of Disease Development?

Background: There are no predictive factors of evolution of cystic fibrosis (CF) screen positive inconclusive diagnosis subjects (CFSPIDs). Aim: to define the role of the second CFTR variant as a predictive factor of disease evolution in CFSPIDs carrying the D1152H variant. Methods: We retrospectively evaluated clinical characteristics and outcome of CFSPIDs carrying the D1152H variant followed at five Italian CF centers. CFSPIDs were divided in two groups: Group A: compound heterozygous for D1152H and a CF-causing variant; Group B: compound heterozygous for D1152H and a: (i) non CF-causing variant, (ii) variant with varying clinical consequences, or (iii) variant with unknown significance. The variants were classified according to CFTR2 mutation database. Results: We enrolled 43 CFSPIDs with at least one D1152H variant: 28 (65.1%) were classified in the group A, and 15 (34.9%) in the Group B. CFSPIDs of group A had the first IRT significantly higher compared to those of group B (p < 0.05) and had a more severe clinical outcome during the follow-up. At the end of the study period, after a mean follow-up of 40.6 months (range 6–91.6), 4 (9.3%) out of 43 CFSPIDs progressed to CFTR-RD or CF. All these subjects were in the group A. Conclusions: The genetic profile could help predict the risk of disease evolution in CFSPIDs carrying D1152H, revealing the subjects that need a more frequent follow-up.

Cystic Fibrosis-Screening Positive Inconclusive Diagnosis: Newborn Screening and Long-Term Follow-Up Permits to Early Identify Patients with CFTR-Related Disorders

Background: Newborn screening (NBS) early-identifies cystic fibrosis (CF), but in CF-screening positive inconclusive diagnosis (CF-SPID) the results of immunoreactive trypsinogen (IRT), molecular analysis and sweat test (ST) are discordant. A percentage of CF-SPID evolves to CF, but data on long-term monitoring are lacking. We describe the follow-up of all CF and CF-SPID identified between 2008 and 2019. Methods: NBS was performed by IRT followed by molecular analysis and ST between 2008 and 2014; double IRT followed by molecular analysis and ST after 2014. Results: NBS revealed 47 CF and 99 CF-SPID newborn, a ratio 1:2.1—the highest reported so far. This depends on the identification by gene sequencing of the second variant with undefined effect in 40 CF-SPID that otherwise would have been defined as carriers. Clinical complications and pulmonary infections occurred more frequently among CF patients than among CF-SPID. Two CF-SPID cases evolved to CF (at two years), while eight evolved to CFTR-related disorders (CFTR-RD), between one and eight years, with bronchiectasis (two), recurrent pneumonia (four, two with sinonasal complications), recurrent pancreatitis (two). No clinical, biochemical or imaging data predicted the evolution. Conclusion: Gene sequencing within the NBS reveals a higher number of CF-SPID and we first describe an approach to early identify CFTR-RD, with relevant impact on their outcome.

The CFTR variant profile of Hispanic patients with cystic fibrosis: Impact on access to effective screening, diagnosis, and personalized medicine

Hispanic patients comprise an appreciable and increasing proportion of patients with cystic fibrosis (CF) in the United States (US). Hispanic patients with CF are known to have increased morbidity and mortality compared to non-Hispanic white patients with CF, and ongoing investigations are underway to identify contributing factors amenable to intervention in order to address the disparate health outcomes. One contributing factor is the different CF transmembrane conductance regulator (CFTR) variant profile observed in Hispanic patients with CF. The most common CFTR variant, p.Phe508del (legacy name F508del), is proportionally underrepresented in Hispanic patients with CF. This difference has implications for prenatal screening, newborn screening (NBS), and CFTR variant-specific therapeutic options. In particular, the recent approval of a highly effective CFTR modulator for patients carrying at least one copy of F508del, elexacaftor/tezacaftor/ivacaftor triple combination therapy, underscores the potential for unequal access to personalized treatment for Hispanic patients with CF. We report the CFTR variant profiles of Hispanic patients with CF and non-CF Hispanic infants with a false-positive New York State CF NBS at a single center in New York City over a 5-year study period, as an opportunity to address the racial and ethnic disparities that currently exist in CF screening, diagnosis, and treatment. In addition to the previously documented disparate prevalence of the CFTR variant F508del in Hispanic patients, we observed two CFTR variants, p.His609Arg (legacy name H609R) and p.Thr1036Asn (legacy name T1036N), frequently identified in our Hispanic patients of Ecuadorian and Mexican ancestry, respectively, that are not well-described in the US population. The presence of population-specific and individually rare CFTR variants in Hispanic patients with CF further accentuates the disparity in health outcomes, as these CFTR variants are often absent from prenatal and NBS CFTR variant panels, potentially delaying diagnosis, and without an approved CFTR variant-specific therapy.