The influence of sex, gestational age, birth weight, blood transfusion, and timing of the heel prick on the pancreatitis-associated protein concentration in newborn screening for cystic fibrosis.

BACKGROUND: Pancreatitis-associated protein (PAP) is currently discussed as a marker in newborn screening (NBS) for cystic fibrosis (CF). However, it is not known if PAP concentrations are influenced by sex, gestational age, birth weight, blood transfusion or time of collection and what this would mean for NBS for CF. METHODS: In 2008 all newborns in part of the Netherlands were screened for CF by an IRT/PAP protocol. PAP concentration was determined by the MucoPAP ELISA (DynaBio), which was modified to a Dissociation Enhanced Lanthanide Fluoroimmunoassay (DELFIA) method following a protocol of PerkinElmer. RESULTS: In healthy newborns, the median PAP concentration was 0.5 µg/l (Interquartile range (IQR 0.3-0.8) whereas this was 3.2 µg/l (IQR 2.0-12.5) in CF infants. PAP concentrations were lower in premature infants 0.94 and 0.91 times for 25 to 31 + 6 weeks GA and 32 to 36 + 6 weeks respectively. A higher PAP concentration was observed in low-birth-weight infants (<2500 gram)(p = 0.001), per 100 gram birth weight gained the PAP concentration decreased with 0.1 %. PAP levels were higher after a blood transfusion, the 95th percentile increased from 1.3 to 3.6 µg/l leading to a higher false-positive rate. The PAP concentration increased when newborn screening was performed more than 168 hours (day 7) after birth (ß = 1.63), the 95th percentile increased from 1.3-1.6 µg/l to 4.0 µg/l after 168 hours (72,874 newborns were screened). CONCLUSION: Sex, birth weight, and gestational age lead to small differences in PAP concentrations without consequences for the screening algorithm. However, blood transfusion as well as performance of the heel prick after 168 hours (7 days) lead to clinically significant higher PAP levels and to a higher risk on a false-positive screening test result.

Novel strategies in newborn screening for cystic fibrosis: a prospective controlled study.

CONTEXT: Newborn screening for cystic fibrosis (CF) is included in many routine programmes but current strategies have considerable drawbacks, such as false-positive tests, equivocal diagnosis and detection of carriers. OBJECTIVE: To assess the test performance of two newborn screening strategies for CF. DESIGN, SETTING AND PARTICIPANTS: In 2008 and 2009, CF screening was added to the routine screening programme as a prospective study in part of The Netherlands. INTERVENTIONS: Two strategies were performed in all newborns. In the first strategy, concentrations of immunoreactive trypsinogen (IRT) and pancreatitis-associated protein (PAP) were measured. In the second method, samples with IRT ≥60 µg/litre were analysed for 36 CFTR mutations, followed by sequencing when a single mutation was detected. Tests were positive only with two identified CFTR mutations. MAIN OUTCOME: Sensitivity, specificity and positive predictive value (PPV) of both screening strategies. RESULTS: 145,499 infants were screened. The IRT/PAP approach showed a sensitivity of 95.0%, a specificity of 99.897% and a PPV of 12.3%. Test properties for the IRT/DNA/sequencing strategy were respectively 100%, 100% and 64.9%. Combining both strategies (IRT/PAP/DNA/sequencing) led to a sensitivity of 95.0%, a specificity of 100% and a PPV of 87.5%. CONCLUSION: In conclusion, all strategies performed well. Although there was no statistically significant difference in test performance, the IRT/DNA/sequencing strategy detected one infant that was missed by IRT/PAP (/DNA/sequencing). IRT/PAP may be the optimal choice if the use of DNA technology must be avoided. If identification of carriers and equivocal diagnosis is considered an important disadvantage, IRT/PAP/DNA/sequencing may be the best choice.

Paediatrics in Amsterdam.

The aim of this update is to describe the paediatric highlights from the 2011 European Respiratory Society (ERS) Annual Congress in Amsterdam, the Netherlands. Abstracts from all seven groups of the ERS Paediatric Assembly (Paediatric Respiratory Physiology, Paediatric Asthma and Allergy, Cystic Fibrosis, Paediatric Respiratory Infection and Immunology, Neonatology and Paediatric Intensive Care, Paediatric Respiratory Epidemiology, and Paediatric Bronchology) are presented in the context of current literature.

Newborn screening for cystic fibrosis.

BACKGROUND: Does newborn screening for cystic fibrosis (CF) improve clinical outcomes, quality of life and survival? OBJECTIVES: To examine whether newborn screening for CF prevents or reduces irreversible organ damage and improves clinical outcomes, quality of life and survival in people with CF without unacceptable adverse effects. SEARCH STRATEGY: We searched the Cochrane Cystic Fibrosis and Genetic Disorders Group Trials Register comprising references identified from electronic database searches, handsearches of relevant journals and abstract books of conference proceedings.The Group's Trials Register last searched: June 2008. SELECTION CRITERIA: Randomised or quasi-randomised controlled trials, published and unpublished, comparing screening to clinical diagnosis in people with CF. DATA COLLECTION AND ANALYSIS: Two authors independently assessed trial eligibility and quality and independently extracted data. Allocation concealment was unclear in both studies and sequence generation adequate in one. MAIN RESULTS: Searches identified six trials. Two trials involving 1,124,483 neonates (210 with CF) with a maximum follow up of 17 years were eligible for inclusion. Varying study designs, outcomes reported and summary measures precluded calculation of pooled estimates and only data from one study were analysed. Severe malnutrition was less common among screened participants. Compared with screened participants, the odds ratio of weight below the tenth percentile was 4.12 (95% CI 1.64 to 10.38) and for height was 4.62 (95% CI 1.69 to 12.61) in the control group.At age seven, 88% of screened participants and 75% of controls had lung function parameters within normal limits of at least 89% predicted. At diagnosis chest radiograph scores were significantly better among screened participants; 33% of screened versus 50% of control participants had Wisconsin chest X-ray (WCXR) scores over five (P = 0.097) and 24% of screened versus 45% of control participants had Brasfield chest X-ray (BCXR) scores under 21 (P = 0.042)). Over time, chest radiograph scores were worse in the screened group (WCXR P = 0.017 and BCXR P = 0.041). Results were no longer significant after adjustment for genotype, pancreatic status, and Pseudomonas aeruginosa-culture results. In screened participants colonisation with Pseudomonas aeruginosa occurred earlier. Estimates suggest diagnosis through screening is less expensive. AUTHORS' CONCLUSIONS: Two randomised controlled trials assessing neonatal screening in CF were identified; data from one study were included. Nutritional benefits are apparent. Screening provides potential for better pulmonary outcomes, but confounding factors influenced long-term pulmonary prognosis of people with CF. Screening seems less expensive than traditional diagnosis.

Newborn blood spot screening for cystic fibrosis with a four-step screening strategy in the Netherlands.

BACKGROUND: Newborn screening for cystic fibrosis (NBSCF) was introduced in the Dutch NBS program in 2011 with a novel strategy. METHODS: Dutch NBSCF consisted of four steps: immuno-reactive trypsin (IRT), Pancreatitis-associated Protein (PAP), DNA analysis by Inno-LiPa (35 mutations), extended gene analysis (EGA) as fourth step and as safety net. Only samples with two CFTR-variants were considered screen-positive, but samples with one disease-causing variant were considered also screen-positive from April 2013. The first 5 years of NBSCF were evaluated during a follow-up ranging from 2 to 6.8 years for sensitivity, specificity, positive predictive value (PPV), ratio of CF/Cystic Fibrosis Screen Positive infants with an Inconclusive Diagnosis (CFSPID) and median age at diagnosis, and were compared to other novel strategies for NBSCF and European Cystic Fibrosis Society (ECFS) Best Practice Standards of Care. RESULTS: NBSCF achieved a sensitivity of 90% (95% CI 82%-94%), specificity of 99.991% (95% CI 99.989%-99.993%), PPV of 63% (95% CI 55%-69%), CF/CFSPID ratio of 4/1, and median age at diagnosis of 22 days, if samples with two variants as well as samples with one disease-causing variant were considered screen-positive. CONCLUSION: The program achieved the goal to minimize the number of false positives and showed a favourable performance but sensitivity and CF/CFSPID ratio did not meet criteria of EFCS Best Standards of Care. Changed cut-off values for PAP and IRT and classification of R117H-7T/9T to non-pathogenic may improve sensitivity to ≥95% and CF/CFSPID ratio to 10/1. PPV is estimated to be around 60%.

CFTR mutations in Turkish and North African cystic fibrosis patients in Europe: implications for screening.

AIMS: To obtain more insight into the variability of the CFTR mutations found in immigrant cystic fibrosis (CF) patients who are living in Europe now, and to estimate the test sensitivity of different frequently used methods of DNA analysis to detect CF carriers or patients among these Turkish or North African immigrants. METHODS: A survey among 373 European CF centers asking which CFTR mutations had been found in Turkish and North African CF patients. RESULTS: 31 and 26 different mutations were reported in Turkish and North African patients, identifying 64.2% (113/176) and 87.4% (118/135) alleles, respectively (p < 0.001). The mean sensitivity (detection rate) of three most common CFTR mutation panels to detect these mutations differed between Turkish and North African people, 44.9% (79/176) versus 69.6% (94/135) (p < 0.001), and can be increased to 57.4% (101/176) and 79.3% (107/135) (p < 0.001), respectively, by expanding these panels with 13 mutations which have been found on two or more alleles. CONCLUSION: 35.8% and 12.6%, respectively, of CF alleles in Turkish and North African patients living in Europe now had not been identified. Among these populations, the test sensitivity of common CFTR mutation panels is insufficient for use in screening programs in Europe, even after expansion with frequent Turkish and North African mutations. This raises questions about whether and how to implement CF carrier and neonatal screening in a multiethnic society.

To know or not to know, disclosure of a newborn carrier screening test result for cystic fibrosis.

PURPOSE: Most newborn screening (NBS) strategies for Cystic Fibrosis (CF) also identify carriers. However, it is unclear if parents want to be informed about their child's carrier status or not. METHODS: Focus group discussions with pregnant couples to explore their opinions about disclosure of a carrier result for CF of their newborn. RESULTS: All (n = 30) wanted to be informed when newborn screening would show their newborn being a CF-carrier. Their main reason was the implication of this knowledge for further family planning. Other family members could be informed and children within the family could be tested. Parents stated they have the right to know, but others also expressed that the choice of not being informed should be offered as well. CONCLUSION: Most parents want to be informed when NBS for CF reveals that their child is a CF-carrier, but the choice of not being informed should also be offered.

Extended gene analysis can increase specificity of neonatal screening for cystic fibrosis.

AIM: To assess whether carriers and patients can be accurately identified by extended gene analysis for cystic fibrosis (CF) in dried blood spots. METHODS: A blinded analysis was performed in 10-mm2 blood spots on Guthrie cards, punched as if to remove material for the IRT test, from 10 CF patients and 10 carriers with known CF mutations. Genomic DNA was isolated. Aliquots of 1 microl dissolved DNA were used for subsequent PCRs. Analysis of the deltaF508 mutation was followed by an oligonucleotide ligation assay. Denaturing gradient gel electrophoresis of the whole CFTR gene was carried out in samples with only one identified mutation. Amplicons revealing an aberrant pattern were sequenced. RESULTS: In all cases, the blood-spot genotype was identical to that previously determined from whole-blood analysis. Estimated time needed to complete the procedure in a series of Guthrie cards was 3-4 wk. CONCLUSION: Extended gene analysis in dried blood spots can discriminate CF patients and carriers. If proven equally reliable in larger series, an approach to neonatal screening in which tests are only considered as screen positive when two CF mutations are found is possible. This can increase the specificity of the screening programme, and carrier detection can practically be avoided.

Cost-effectiveness of 4 neonatal screening strategies for cystic fibrosis.

OBJECTIVES: The purpose of this work was to assess the costs of 4 neonatal screening strategies for cystic fibrosis in relation to health effects. In each strategy, the first test was the measurement of serum concentration of immunoreactive trypsin. The second step consisted of either a second immunoreactive trypsin test (strategy 1) or a multiple mutation analysis (strategy 2). In strategies 3 and 4, a third step was added to strategy 2: a second immunoreactive trypsin test (strategy 3) or an extended mutation analysis of the cystic fibrosis gene, that is, a denaturing gradient gel electrophoresis analysis (strategy 4). METHODS: We conducted an economic-modeling exercise in the Netherlands based on published data and expert opinions. Subjects were a hypothetical cohort of 200 000 neonates, the approximate number of children born annually in the Netherlands, and we assessed the costs and number of life-years gained as a result of neonatal screening for cystic fibrosis. The costs and effects of changes in reproductive decisions because of neonatal screening were also assessed. RESULTS: Immunoreactive trypsin + immunoreactive trypsin had the most favorable cost-effectiveness ratio of 24,800 euro per life-year gained. Immunoreactive trypsin + DNA + denaturing gradient gel electrophoresis achieved more health effects than immunoreactive trypsin + DNA + immunoreactive trypsin at lower cost. The incremental costs per life-year gained of the immunoreactive trypsin + DNA + denaturing gradient gel electrophoresis strategy compared with the immunoreactive trypsin + immunoreactive trypsin strategy were 130,700 euro, whereas the incremental costs of the immunoreactive trypsin + DNA strategy compared with the immunoreactive trypsin + DNA + denaturing gradient gel electrophoresis strategy were 2,154,300 euro. When changes in reproductive decisions as a result of neonatal screening are also taken into account, neonatal screening for cystic fibrosis may lead to financial savings of approximately 1.8 million euro annually, depending on the screening strategy used. CONCLUSIONS: Cystic fibrosis screening for neonates is a good economic option, and positive health effects can also be expected. Immunoreactive trypsin + immunoreactive trypsin and immunoreactive trypsin + DNA + denaturing gradient gel electrophoresis are the most cost-effective strategies.

Review of outcomes of neonatal screening for cystic fibrosis versus non-screening in Europe.

We reviewed the published results of European prospective cohort and controlled studies and 1 randomized controlled study to assess whether newborn screening (NBS) for cystic fibrosis (CF) leads to an improved prognosis. We used long-term survival, early mortality, nutritional and pulmonary status, and the number of hospital admissions as outcome measures. Effects on reproductive behavior of the parents and relatives were also assessed. In 2 studies, a similar trend for improved long-term survival rate of the screened cohort was observed, whereas in 2 other studies CF NBS appeared to prevent CF-related deaths in infancy and early childhood. Screened patients born in the last 2 decades showed normal growth for height and weight from infancy until late childhood. In most studies, patients who were screened were found to have less lung damage than their non-screened peers. CF NBS significantly reduced the number of affected children who ever required hospitalization. In Brittany, France, a reduction of 15.7% in CF prevalence at birth was attributed to the introduction of a NBS program for CF. We conclude that there is accumulating evidence that CF NBS prevents early CF-related deaths and leads to a substantial and prolonged health gain for patients with CF.

Early versus late diagnosis: psychological impact on parents of children with cystic fibrosis.

OBJECTIVES: To explore the relationship between the period preceding diagnosis and the way parents of children with cystic fibrosis (CF) experience and handle their child's disease. DESIGN: A retrospective study. SETTING: CF Center "Noordwest Nederland," the Netherlands. PARTICIPANTS: Participants were the parents of children <13 years old with CF who were treated at the CF Center "Noordwest Nederland." The participants were divided into 2 groups according to the duration of prediagnostic period: <3 months (defined as early diagnosis) and >or=3 months (defined as late diagnosis). MAIN OUTCOME MEASURES: Experience of the prediagnostic period, contact with the medical profession, coping, future perspective, and attitudes toward neonatal screening for CF. RESULTS: Parents of 55 children were eligible for study participation; 45 were enrolled. Retrospectively, the period preceding an early diagnosis was less negatively experienced by parents than the period preceding a late diagnosis. Parents of children with an early diagnosis had retrospectively more confidence in the medical profession before confirmation of diagnosis. In general, parents in this study used adaptive coping styles. Duration of prediagnostic period was not significantly related to future perspective. Hopelessness seemed to be mainly determined by a severe course of disease as experienced by the parents. Ninety-eight percent of all parents were in favor of neonatal screening for CF. CONCLUSIONS: A short prediagnostic period is associated with less negative feelings and increased confidence in the medical profession among parents of children with CF. Neonatal screening for CF may be of benefit to parents by removing the stress of a delayed diagnosis.