Clinical and economic aspects of newborn screening for severe combined immunodeficiency: DEPISTREC study results.

PURPOSE: Severe combined immunodeficiency (SCID) refers to a group of genetic disorders characterized by greatly compromised cellular and humoral immunity. Children with SCID are asymptomatic at birth, but they die from infections within the first months of life if not treated. Quantification of T-cell receptor excision circles is an extremely sensitive screening method for detecting newborns who may have SCID.The goal of the DEPISTREC study was to evaluate the feasibility of nationwide newborn screening for severe T-cell lymphopenia in France as well as its economic and clinical utility. METHODS: The test universally used for neonatal screening for SCID was the quantification of TRECs on Guthrie cards. We compared a group of 190,517 babies from 48 maternities across the country who underwent newborn SCID screening with a control group of 1.4 million babies out of whom 28 were diagnosed with SCID without such screening during the course of the study. RESULTS: Within the screening group, 62 babies were found to be lymphopenic, including three with SCID. The cost of screening ranged from 4.7€ to €8.15 per newborn. The average 18-month cost was €257,574 vs €204,697 in the control group. CONCLUSIONS: In this large-scale study, we demonstrate that routine SCID screening is feasible and effective. This screening offers the additional benefit of aiding in the diagnosis of non-SCID lymphopenia. Economic evaluation allowed us to calculate the cost per test. Newborn screening may also prevent death by SCID before any curative treatment can be administered. The difference in cost between screened and control children could not be ascertained because of the very low numbers and death of one of the children tested.

Optimization of the French cystic fibrosis newborn screening programme by a centralized tracking process.

Objectives To evaluate the French cystic fibrosis newborn screening algorithm, based on data tracked by a centralized monitoring process, from 2002 to 2014. The programme aimed to attain European Standards in terms of positive predictive value, sensitivity, the ratio of screen positive patients diagnosed with cystic fibrosis to infants who screen positive but with inconclusive diagnosis (CFSPID), and time to diagnosis. Methods Retrospective analysis of programme performance, compliance with the algorithm, and changes in screening strategy. Results Modifications in the flow chart protocol improved the positive predictive value to 0.31 while maintaining the sensitivity at 0.95. Among infants diagnosed with cystic fibrosis, or identified as CFSPID, sweat test results were obtained for 94%, and two mutations were identified after exhaustive screening for the gene, when applicable, in 99.6%. The rate of pending diagnosis was very low (0.5%). The ratio of infants with cystic fibrosis:CFSPID was 6.3:1. Age at initial visit at the CF centre was ≤ 35 days, respectively, in 53%/26%. Conclusion Performances were in agreement with European standards, but timeliness of initial visit needed improvement. Our data complement an accumulating body of evidence demonstrating that attention must be paid to such ethical considerations as limiting carrier detection and inconclusive diagnosis. Newborn screening programmes should have a rigorous centralized monitoring process to warrant adjustments for improving performance to attain consensus guidelines.

Increased incidence of congenital hypothyroidism in France from 1982 to 2012: a nationwide multicenter analysis.

PURPOSE: Recent studies have shown an increased incidence of congenital hypothyroidism over the past 2 or 3 decades. The etiology of this change is unknown, but it has been related by several authors to lowering of cutoffs. We sought to determine whether the incidence of congenital hypothyroidism (CH) in France has changed. METHODS: We analyzed data from the nationwide neonatal screening program for CH during the period 1982-2012. We included all children having thyroid-stimulating hormone values above the threshold and for whom diagnosis of CH confirmed by the pediatrician. We estimated multicentric temporal trends in the annual incidence rates adjusted for screening methods for thyroid dysgenesis and eutopic gland. RESULTS: We found 6622 cases of CH (28.0 per 100,000 newborns); 1895 had a eutopic gland, and 4727 had thyroid dysgenesis. The incidence of eutopic glands showed a significant annual average increase of (5.1%; 95% confidence interval: 4.3-5.9) regardless of the screening method or screening center. This increase was confirmed in severe cases (thyroid-stimulating hormone ≥ 50: 2.1%; 95% confidence interval, 1.4-2.9). The incidence of dysgenesis remained constant. CONCLUSIONS: The incidence of eutopic glands increased in France, not only in mild forms but also in severe cases.

PAP assays in newborn screening for cystic fibrosis: a population-based cost-effectiveness study.

OBJECTIVES: To compare the cost effectiveness of adding a pancreatitis-associated protein (PAP) assay to common immunoreactive trypsinogen (IRT) and DNA cystic fibrosis (CF) newborn screening strategies. METHODS: Using data collected on 553,167 newborns, PAP cut-offs were calculated based on non-inferiority of the detection rates of classical forms of CF. Cost effectiveness was considered from the third-party payer's perspective using only direct medical costs, and the unit costs of PAP assays were assessed based on a micro-costing study. Robustness of the cost-effectiveness estimates was assessed, taking the secondary outcomes of screening (ie. detecting mild forms and CF carriers) into account. RESULTS: IRT/DNA, IRT/PAP, and IRT/PAP/DNA strategies had similar detection rates for classical forms of CF, but the strategies involving PAP assays detected smaller numbers of mild forms of CF. The IRT/PAP strategy was cost-effective in comparison with either IRT/DNA or IRT/PAP/DNA. IRT/PAP/DNA screening was cost-effective in comparison with IRT/DNA if relatively low value was assumed to be attached to the identification of CF carriers. CONCLUSIONS: IRT/PAP strategies could be strictly cost-effective, but dropping DNA would mean the test could not detect CF carriers. IRT/PAP/DNA strategies could be a viable option as they are significantly less costly than IRT/DNA, but still allow CF carrier detection.

Comprehensive CFTR gene analysis of the French cystic fibrosis screened newborn cohort: implications for diagnosis, genetic counseling, and mutation-specific therapy.

PURPOSE: Newborn screening (NBS) for cystic fibrosis (CF) was implemented throughout France in 2002. It involves a four-tiered procedure: immunoreactive trypsin (IRT)/DNA/IRT/sweat test [corrected] was implemented throughout France in 2002. The aim of this study was to assess the performance of molecular CFTR gene analysis from the French NBS cohort, to evaluate CF incidence, mutation detection rate, and allelic heterogeneity. METHODS: During the 8-year period, 5,947,148 newborns were screened for cystic fibrosis. The data were collected by the Association Française pour le Dépistage et la Prévention des Handicaps de l'Enfant. The mutations identified were classified into four groups based on their potential for causing disease, and a diagnostic algorithm was proposed. RESULTS: Combining the genetic and sweat test results, 1,160 neonates were diagnosed as having cystic fibrosis. The corresponding incidence, including both the meconium ileus (MI) and false-negative cases, was calculated at 1 in 4,726 live births. The CF30 kit, completed with a comprehensive CFTR gene analysis, provides an excellent detection rate of 99.77% for the mutated alleles, enabling the identification of a complete genotype in 99.55% of affected neonates. With more than 200 different mutations characterized, we confirmed the French allelic heterogeneity. CONCLUSION: The very good sensitivity, specificity, and positive predictive value obtained suggest that the four-tiered IRT/DNA/IRT/sweat test procedure may provide an effective strategy for newborn screening for cystic fibrosis.

Neonatal screening for cystic fibrosis: comparing the performances of IRT/DNA and IRT/PAP.

BACKGROUND: French health authorities promoted a study on 553,167 newborns comparing the performances of IRT/DNA and IRT/PAP for CF newborn screening. METHODS: In parallel to IRT/DNA, PAP was assayed in newborns with IRT>50 µg/L. Provisional PAP cutoffs at 3.0 µg/L when 50100 were used. Positive newborns were subjected to sweat test. Optimal cutoffs were established by a non-inferiority method. RESULTS: 95 CF newborns were identified (83 classical forms (ClF), including 9 meconium ileus (MI), and 12 atypical (mild) forms (AF) Of them, IRT/DNA identified 85 (73 ClF including 5 MI and 12 AF). PAP cutoffs at 1.8 µg/L when 50< IRT<100 µg/L and 0.6 µg/L when IRT>100 µg/L would identify 82 CF: 77 ClF, including 8 MI, and 5 AF. The number of sweat tests was 314 and 1039 in the IRT/DNA and IRT/PAP strategies, respectively. CONCLUSIONS: Using the optimal cutoffs, the sensitivity of the IRT/PAP strategy would not be inferior to that of IRT/DNA if identification of MF is not required.

Cascade testing in families of carriers identified through newborn screening in Western Brittany (France).

BACKGROUND: Newborn screening (NBS) for cystic fibrosis (CF) can lead to the detection of healthy carriers. We report a unique assessment of family testing following the identification of carriers by NBS for over 20 years, in an area where CF is frequent. METHODS: We reviewed all of the carriers identified by NBS between 1991 and 2010 and registered the tests done in those families. RESULTS: NBS identified 0.1% of the newborns as carriers, which correspond only to 2.6% of the expected carriers born within the period, and 1/3 of those with an increased IRT level. Of the 195 families, 75.9% requested testing (2.5 tests per family). We identified 183 carriers and five 1-in-4 risk couples. Reassurance about genetic status was provided to 96% of the couples. CONCLUSIONS: Carriers detected by NBS appeared to be well managed in our area, and cascade testing that informs on genetic status seems relatively active.

Whole-body post-mortem computed tomography compared with autopsy in the investigation of unexpected death in infants and children.

OBJECTIVES: To investigate the contribution of whole-body post-mortem computed tomography (PMCT) in sudden unexpected death in infants and children. METHODS: Forty-seven cases of sudden unexpected death in children investigated with radiographic skeletal survey, whole-body PMCT and autopsy were enrolled. For imaging interpretation, non-specific post-mortem modifications and abnormal findings related to the presumed cause of death were considered separately. All findings were correlated with autopsy findings. RESULTS: There were 31 boys and 16 girls. Of these, 44 children (93.6 %) were younger than 2 years. The cause of death was found at autopsy in 18 cases (38.3 %), with 4 confirmed as child abuse, 12 as infectious diseases, 1 as metabolic disease and 1 as bowel volvulus. PMCT results were in accordance with autopsy in all but three of these 18 cases. Death remains unexplained in 29 cases (61.7 %) and was correlated with no abnormal findings on PMCT in 27 cases. Major discrepancies between PMCT and autopsy findings concerned pulmonary analysis. CONCLUSIONS: Whole-body PMCT may detect relevant findings that can help to explain sudden unexpected death and is essential for detecting non-accidental injuries. We found broad concordance between autopsy and PMCT, except in a few cases of pneumonia. It is a non-invasive technique acceptable to relatives. KEY POINTS: • Whole-body post-mortem computed tomography (PMCT) is an effective non-invasive method. • Whole-body PMCT is essential for detecting child abuse in unexpected death. • There is concordance on cause of death between PMCT and autopsy. • Whole-body PMCT could improve autopsy through dissection and sampling guidance. • PMCT shows findings that may be relevant when parents reject autopsy.

Evidence for decline in the incidence of cystic fibrosis: a 35-year observational study in Brittany, France.

BACKGROUND: Cystic fibrosis (CF) is an autosomal recessive disorder whose incidence has long been estimated as 1/2500 live births in Caucasians. Expanding implementation of newborn screening (NBS) programs now allows a better monitoring of the disease incidence, what is essential to make reliable predictions for disease management. This study assessed time trends in the birth incidence of CF over a long period (35 years: 1975-2009) in an area where CF is frequent (Brittany, France) and where NBS has been implemented for more than 20 years. METHODS: This study enrolled CF patients born in Brittany between January 1st 1975 and December 31st 2009 (n = 483). Time trends in incidence were examined using Poisson regression and mainly expressed using the average percent change (APC). RESULTS: The average number of patients born each year declined from 18.6 in the late 1970's (period 1975-79) to 11.6 nowadays (period 2005-09). The corresponding incidence rates dropped from 1/1983 to 1/3268, which represented a decline close to 40% between these two periods (APC = -39.3%, 95% CI = -55.8% to -16.7%, p = 0.0020). A clear breakpoint in incidence rate was observed at the end of the 1980's (p < 0.0001). However, the incidence rate has remained quite stable since that time (annual APC = -1.0%, 95% CI = -3.0% to 1.1%, p = 0.3516). CONCLUSIONS: This study provides an accurate picture of the evolution of the incidence of a genetic disease over a long period and highlights how it is influenced by the health policies implemented. We observed a 40% drop in incidence in our area which seems consecutive to the availability of prenatal diagnosis.

Efficiency of neonatal screening for congenital adrenal hyperplasia due to 21-hydroxylase deficiency in children born in mainland France between 1996 and 2003.

OBJECTIVE: To assess the efficiency of the French national screening program for 21-hydroxylase deficiency (21-OHD). Neonatal screening for congenital adrenal hyperplasia due to 21-OHD is mainly intended to prevent death due to salt wasting but remains controversial because of the number of false-positive results and the ease with which most female cases can be identified by virilized genitalia at birth. DESIGN: Population-based study. SETTING: National neonatal screening program, pediatric endocrinologists nationwide, and reference center for genotyping. PARTICIPANTS: All neonates screened for 21-OHD in mainland France between January 1, 1996, and December 31, 2003. OUTCOME MEASURES: Screening efficiency indicators, disease severity, contribution of screening to early diagnosis, and disease-specific mortality before and during the study period. RESULTS: A total of 6,012,798 neonates were screened; results in 15,407 were considered positive for 21-OHD. Three hundred eighty-three cases were identified, giving a prevalence of 1 for every 15,699 births. The positive predictive value of screening was 2.3% (95% CI, 2.1%-2.6%), with a sensitivity of 93.5% (90.9%-95.9%) and a specificity of 99.7% (99.7%-99.7%). The false-positive rate was particularly high in preterm infants, for which the positive predictive value was 0.4% (95% CI, 0.2%-0.5%). Screening allowed clinical diagnosis in 162 of 383 cases (42.3%), with the others being detected clinically or through family history. There was a trend toward declining neonatal mortality due to 21-OHD. CONCLUSIONS: In this large population-based study, the efficiency of routine 21-OHD screening was moderate in neonates born at term and very low in preterm neonates. We recommend the discontinuation of screening, as currently performed in France, in preterm neonates.

Formative evaluation to improve prevention of sudden infant death syndrome (SIDS): a prospective study.

AIM: To evaluate formative evaluation, a pedagogic method that sensitizes mothers to sudden infant death syndrome (SIDS), as a new way to improve prevention of SIDS. METHODS: Prospective and randomized study. Mothers in a test group (n = 148) received an educative questionnaire about SIDS during maternity stay. Three months later, we evaluated, by a telephonic interview, their scores of knowledge and observance of the recommendations in comparison with a control group (n = 144). RESULTS: Mothers' scores at the educative questionnaire was 5.12 (1.52) [mean(standard deviation)]. The scores performed 3 months later were better in test group for knowledge [7.64 (1.56) vs. 7.16 (1.61), p < 0.01] and for observance [8.28 (1.51) vs. 7.62 (1.72), p < 0.001]. Logistic regression analysis confirmed the benefits in test group regarding knowledge of SIDS risk factors [ORa = 1.69 (1.02-2.77), p < 0.05], of the advice to avoid overheating infants [ORa = 2.50 (1.43-4.38), p < 0.01] and of the risks of bed sharing [ORa = 2.7 (1.6-4.5), p < 0.001]. There was a significant association between non-compliance with the sleeping position recommendation and unemployment (p < 0.01) and absence of postsecondary school education (p < 0.01). CONCLUSION: Formative evaluation using an educative questionnaire could improve maternal awareness on SIDS risk factors and their compliance with recommendations about SIDS prevention.

Subtle health impairment and socioeducational attainment in young adult patients with congenital hypothyroidism diagnosed by neonatal screening: a longitudinal population-based cohort study.

CONTEXT: Screening programs resulting in the early treatment of patients with congenital hypothyroidism (CH) have successfully improved neurodevelopmental outcome, but little is known about long-term health. OBJECTIVES: The aim of the study was to assess health status, and socioeconomic attainment, for a population-based registry of young adult patients. DESIGN, SETTING, AND PARTICIPANTS: All 1748 eligible patients diagnosed during the first decade after the introduction of neonatal screening in France were invited to participate in this study at a median age of 23.4 yr. Completed questionnaires were obtained from 1202 of the selected patients. The comparison group included 5817 subjects from the last French Decennial Health Survey. MAIN OUTCOME MEASURES: Health indicators including medical conditions, hearing and visual status, sociodemographic characteristics, and quality of life were measured. RESULTS: Patients with CH were significantly more likely than their peers to report associated chronic diseases (5.7 vs. 2.9%), hearing impairment (9.5 vs. 2.5%), visual problems (55.4 vs. 47.9%), and being overweight with a body mass index of at least 25 kg/m(2) (22.8 vs. 15.7%) (P < 0.0001). Furthermore, fewer patients attained the highest socioeconomic category (14.6 vs. 23.1%) and were in full-time employment (39.9 vs. 44.8%) (P < 0.0001). They were more likely to still be living with their parents and had a lower health-related quality of life than their healthy peers, particularly for mental dimensions, with a mean difference for the mental summary component of 0.35 SD score (P < 0.0001). CH severity at diagnosis, treatment adequacy, and the presence of other chronic health conditions were the main determinants of educational achievement and health-related quality of life scores. CONCLUSION: These findings highlight the need for careful monitoring of neurosensory functioning, weight, and long-term treatment adequacy throughout childhood and adulthood.

Clinical phenotype and genotype of children with borderline sweat test and abnormal nasal epithelial chloride transport.

RATIONALE: The diagnosis of cystic fibrosis (CF) is based on a characteristic clinical picture in association with a sweat chloride (Cl(-)) concentration greater than 60 mmol/L or the identification of two CF-causing mutations. A challenging problem is the significant number of children for whom no definitive diagnosis is possible because they present with symptoms suggestive of CF, a sweat chloride level in the intermediate range between 30 and 60 mmol/L, and only one or no identified CF-causing mutation. OBJECTIVES: To investigate the function of the cystic fibrosis transmembrane conductance regulator (CFTR) protein in the airways of children with intermediate sweat tests and inconclusive genetic findings in correlation with clinical phenotype and genotype. METHODS: We developed a composite nasal potential difference (NPD) diagnostic score to discriminate patients with CF from non-CF patients. We tested NPD in 50 children (age, 6 mo to 18 yr) with equivocal diagnoses and correlated the NPD diagnostic score with clinical phenotypes and genotypes. MEASUREMENTS AND MAIN RESULTS: Fifteen of the 50 children had NPD scores in the CF range. Eight of the 15 carried two CFTR mutations compared with only 5 of the 35 children with normal NPD scores (P = 0.01). They were significantly younger at evaluation and had recurrent lower respiratory tract infections, chronic productive coughs, and chronic Staphylococcus aureus colonization significantly more often than the 35 children with normal NPD results. CONCLUSIONS: Evaluation of CFTR function in the nasal epithelium of children with inconclusive CF diagnoses can be a useful diagnostic tool and help clinicians to individualize therapeutic strategy.

Measurement of nasal potential difference in young children with an equivocal sweat test following newborn screening for cystic fibrosis.

BACKGROUND: A challenging problem arising from cystic fibrosis (CF) newborn screening is the significant number of infants with hypertrypsinaemia (HIRT) with sweat chloride levels in the intermediate range and only one or no identified CF-causing mutations. OBJECTIVES: To investigate the diagnostic value for CF of assessing CF transmembrane conductance regulator (CFTR) protein function by measuring nasal potential difference in children with HIRT. METHODS: A specially designed protocol was used to assess nasal potential difference (NPD) in 23 young children with HIRT (3 months-4 years) with inconclusive neonatal screening. Results were analysed with a composite score including CFTR-dependent sodium and chloride secretion. Results were correlated with genotype after extensive genetic screening and with clinical phenotype at follow-up 3 years later. RESULTS: NPD was interpretable for 21 children with HIRT: 13 had NPD composite scores in the CF range. All 13 were finally found to carry two CFTR mutations. At follow-up, nine had developed a chronic pulmonary disease consistent with a CF diagnosis. The sweat test could be repeated in nine children, and six had sweat chloride values >or=60 mmol/l. Of the eight children with normal NPD scores, only two had two CFTR mutations, both wide-spectrum mutations. None had developed a CF-like lung disease at follow-up. The sweat test could be reassessed in five of these eight children and all had sweat chloride values <60 mmol/l. CF diagnosis was ruled out in six of these eight children. CONCLUSION: Evaluation of CFTR function in the nasal epithelium of young children with inconclusive results at CF newborn screening is a useful diagnostic tool for CF.

Psychological effects of false-positive results in cystic fibrosis newborn screening: a two-year follow-up.

OBJECTIVE: To evaluate parental stress after a false-positive result at the time of the cystic fibrosis (CF) newborn screening (NBS), attributable to heterozygotism or persistent hypertrypsinemia. STUDY DESIGN: A prospective study was conducted in 86 French families at 3, 12, and 24 months after NBS. A psychologist conducted interviews with a questionnaire, the Perceived Stress Scale, and the Vulnerable Child Scale. RESULTS: Overall, 96.5% of parents said they had been anxious at the time of the sweat test. However, 86% felt entirely reassured 3 months after the test. The mean Perceived Stress Scale score did not differ from that observed in the French population. Mean Vulnerable Child Scale scores were high, associated with a low Parental Perception of Child Vulnerability. These results did not differ significantly at 1 and 2 years. In total, 86% to 100% of families no longer worried about CF. All parents stated that they would have the test performed again for another child. CONCLUSIONS: CF NBS can lead to false-positive results, causing parental anxiety, which quickly decreases after a sweat test performed soon after the phone call.

Pulmonary outcome differences in U.S. and French cystic fibrosis cohorts diagnosed through newborn screening.

BACKGROUND: A comparison of the longitudinal progression of lung disease in cystic fibrosis patients identified through newborn screening (NBS) in cohorts located in two different countries has never been performed and was the primary objective of this study. METHODS: The study included 56 patients in Brittany diagnosed through NBS between 1989 and 1994 and 69 similar patients in Wisconsin between 1985 and 1994. The onset and progression of lung disease was radiographically quantified using the Wisconsin Chest X-ray (WCXR) scoring system. A single pediatric pulmonologist blinded to all identifiers scored the films. RESULTS: Generalized estimating equation analyses adjusted for age, genotype, sex, pancreatic insufficiency, and meconium ileus showed worse WCXR scores in Brittany patients compared to Wisconsin patients (average score difference=4.48; p<0.001). Percent predicted FEV1 was also worse among Brittany patients (p<0.001). CONCLUSIONS: The finding of milder radiographically-quantified lung disease using the WCXR scoring system, as well as better FEV1 values, may be explained by variations in nutrition, environmental exposures, or healthcare delivery.

The importance of sweat testing for older siblings of patients with cystic fibrosis identified by newborn screening.

We report cystic fibrosis (CF) care center instructions for sweat testing in older siblings after implementation of the French nationwide newborn screening program, and we evaluate the incidence of unrecognized CF. Nearly 9% of families with an infant screened for CF were unaware of an affected older sibling. We strongly recommend sweat testing for all first-degree older children.