International Journal of Neonatal Screening

10 pages, 941 KB

Open AccessArticle

Next-Generation Sequencing for Cystic Fibrosis: Florida Newborn Screening Experience

by Deanna M. Green, Jean Polasky, Mark Weatherly, Heather Stalker, Colleen Blanchard, Cheryl Kushner, Marisa Couluris, Patricia Ryland, Iruvanti Sunitha, Joseph Fong, Sandra Crump, Emily Reeves and Kristin Barnette

Int. J. Neonatal Screen. 2025, 11(4), 94; https://doi.org/10.3390/ijns11040094 (registering DOI) - 14 Oct 2025

Abstract

Cystic fibrosis (CF) is an autosomal recessive genetic condition affecting nearly 1 in 4000 newborns. Early diagnosis and treatment have been shown to improve the care of individuals with CF, which is enhanced through newborn screening (NBS). The state of Florida has been [...] Read more.

Cystic fibrosis (CF) is an autosomal recessive genetic condition affecting nearly 1 in 4000 newborns. Early diagnosis and treatment have been shown to improve the care of individuals with CF, which is enhanced through newborn screening (NBS). The state of Florida has been performing CF NBS since 2007, and in 2022, Florida implemented enhanced next generation sequencing (NGS). The goal of this change was to identify individuals from under-represented racial and ethnic groups, who may have rare or de novo variants. NBS screening for CF involved a first tier with immunoreactive trypsinogen (IRT) ≥ 50 or the top 4% of daily specimens, whichever is lower, reflexing to a second tier. As of 2022, the second tier has evolved to an expanded sequence with an Agena 74-variant panel. Single variants would then reflex to the third tier utilizing NGS. NGS is able to confirm what is detected in second-tier testing, adding variants not included in the Agena panel, and refining the TG replications for Poly-T variants to determine pathogenicity of 5T results. When there is a variant of varying clinical consequence between the two databases, the most conservative classification is selected. Individuals with variants would then be referred to one of the contracted CF NBS referral centers for confirmatory sweat chloride testing (sweat). With implementation of NGS, referrals nearly tripled in 2022–2024, with 538 referrals in 2019; 485 in 2020; and 805 in 2021; followed by 1223 referrals made in 2022; 1146 in 2023; and 1294 in 2024. In 2022–2024, 71% of referrals to the contracted NBS CF referral centers were for single variant results, and no cases of CF were identified from these referrals. The number of CF cases remained about the same, ranging from 23 to 40 through the years 2019–2024. The number of CRMS/CFSPID cases, however, tripled going from 10 to 12 in 2019–2022 to over 100 in 2024. The reason for this change seems to be related to complex heterozygous genetic variants as opposed to abnormal sweat. Implementation of NGS for CF in Florida led to a significant increase in the identification of CFTR variants which affected all aspects of the NBS CF process, from an increased workload on the NBS laboratory and follow-up staff, to an increase in referrals to the NBS CF referral centers. The majority of referrals were for single-variant results, which meant the infants had a very low likelihood of having CF. It is recommended that when an algorithm involving NGS is utilized, one should verify that there are appropriate processes for sweat, including the manner in which single-variant CF results are handled, avoiding unnecessary healthcare utilization. Full article

(This article belongs to the Special Issue Advances in Cystic Fibrosis Newborn Screening: From Laboratory Testing to Diagnosis)

2 pages, 141 KB

Open AccessEditorial

Congenital Hypothyroidism: Moving Ahead, but a Long Way Still to Go

by Ernest M. Post and Natasha L. Heather

Int. J. Neonatal Screen. 2025, 11(4), 93; https://doi.org/10.3390/ijns11040093 (registering DOI) - 13 Oct 2025

Abstract

Newborn screening (NBS) for congenital hypothyroidism (CH) has been going on for more than fifty years, but we are still learning more about the process and the disease(s) [...] Full article

(This article belongs to the Special Issue Newborn Screening for Congenital Hypothyroidism)

17 pages, 335 KB

Open AccessReview

Practical Considerations for the Diagnosis and Management of Isovaleryl-CoA-Dehydrogenase Deficiency (Isovaleric Acidemia): Systematic Search and Review and Expert Opinions

by Eva Thimm, Anselma Riederer, Jerry Vockley, Dries Dobbelaere, Monique Williams, Anita MacDonald, Katharina Dokoupil, Ulrich A. Schatz and Regina Ensenauer

Int. J. Neonatal Screen. 2025, 11(4), 92; https://doi.org/10.3390/ijns11040092 - 10 Oct 2025

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Abstract

Isovaleric acidemia (IVA, OMIM 243500) is an inherited disorder of leucine metabolism caused by a deficiency of isovaleryl-CoA dehydrogenase (IVD), leading to an accumulation of isovaleric acid and its derivates 3-hydroxyisovaleric acid, isovaleryl (C5)-carnitine and isovalerylglycine in body fluids. The clinical presentation is [...] Read more.

Isovaleric acidemia (IVA, OMIM 243500) is an inherited disorder of leucine metabolism caused by a deficiency of isovaleryl-CoA dehydrogenase (IVD), leading to an accumulation of isovaleric acid and its derivates 3-hydroxyisovaleric acid, isovaleryl (C5)-carnitine and isovalerylglycine in body fluids. The clinical presentation is highly variable, ranging from life-threatening metabolic crises with metabolic acidosis and hyperammonemia to a clinically asymptomatic only biochemical phenotype. Newborn screening for IVA has been established in many countries. Treatment consists of a protein-restricted diet combined with supplementation of carnitine and/or glycine and emergency treatment in catabolic episodes. Still, evidence-based recommendations for the diagnosis and management of IVA patients with various phenotypes are lacking. Therefore, a systematic search and review of the literature was conducted to make suggestions for the care of patients with IVA based on both the available scientific evidence and consensus-derived expert conclusions. Based on a comprehensive set of literature data published between 1966 and 2024, 15 statements were phrased on the presentation, diagnosis, management, and outcome of IVA involving clinical, biochemical, and nutrition expertise. These statements can serve as a basis for more standardized care for IVA. Full article

22 pages, 1591 KB

Open AccessArticle

Analytical Validation of a Genomic Newborn Screening Workflow

by Kristine Hovhannesyan, Laura Helou, Benoit Charloteaux, Valerie Jacquemin, Flavia Piazzon, Myriam Mni, Charlotte Flohimont, Corinne Fasquelle, Davood Mashhadizadeh, Tamara Dangouloff, Vincent Bours, Laurent Servais, Leonor Palmeira and François Boemer

Int. J. Neonatal Screen. 2025, 11(4), 91; https://doi.org/10.3390/ijns11040091 - 10 Oct 2025

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Abstract

Newborn screening (NBS) has evolved significantly since its inception, yet many treatable rare diseases remain unscreened due to technical limitations. The BabyDetect study used gene panel sequencing to expand NBS to treatable conditions not covered by conventional biochemical screening. We present here the [...] Read more.

Newborn screening (NBS) has evolved significantly since its inception, yet many treatable rare diseases remain unscreened due to technical limitations. The BabyDetect study used gene panel sequencing to expand NBS to treatable conditions not covered by conventional biochemical screening. We present here the analytical validation of this workflow, assessing sensitivity, precision, and reproducibility using dried blood spots from newborns. We implemented strict quality control thresholds for sequencing, coverage, and contamination, ensuring high reliability. Longitudinal monitoring confirmed consistent performance across more than 5900 samples. Automation of DNA extraction improved scalability, and a panel redesign enhanced the coverage and selection of targeted regions. By focusing on known pathogenic/likely pathogenic variants, we minimized false positives and maintained clinical actionability. Our findings demonstrate that gene panel sequencing-based NBS is feasible, accurate, and scalable, addressing critical gaps in current screening programs. Full article

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10 pages, 216 KB

Open AccessArticle

Caregivers’ Emotional Responses Triggered by a False-Positive VLCADD in Newborn Screening in Oita Prefecture

by Sakura Morishima, Yumi Shimada and Kenji Ihara

Int. J. Neonatal Screen. 2025, 11(4), 90; https://doi.org/10.3390/ijns11040090 - 8 Oct 2025

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Abstract

Neonatal screening programs for inborn errors of metabolism are essential for early diagnosis and intervention. However, false-positive results can cause unnecessary psychological stress for caregivers. This study investigated the emotional impact on a small number of caregivers in Oita Prefecture in Japan, whose [...] Read more.

Neonatal screening programs for inborn errors of metabolism are essential for early diagnosis and intervention. However, false-positive results can cause unnecessary psychological stress for caregivers. This study investigated the emotional impact on a small number of caregivers in Oita Prefecture in Japan, whose infants received false-positive screening results for very long-chain acyl-CoA dehydrogenase deficiency (VLCADD). Particular attention was given to caregivers’ concerns regarding episodes of transient fasting suggestive of nutritional deficiency, as well as their perspectives on appropriate feeding practices for newborns. Nineteen infants in Oita Prefecture were identified as having elevated acylcarnitines, which were later confirmed as false positives. Of these cases, 11 mothers consented to participate in a survey and long-term growth evaluation using health check records. Thirty children with normal screening results were included as controls. While no differences in physical growth were found between groups by 3.5 years of age, some mothers of false-positive infants reported persistent anxiety. Their concerns included regret for inadequate breastfeeding and latent adverse effects on long-term growth or development. Conversely, caregivers’ anxiety diminished over time as they directly observed their infants’ normal growth and development. No regret was expressed regarding breastfeeding, and concerns about VLDCAD were not observed. Caregivers’ responses may help reduce their psychological burden. Full article

11 pages, 859 KB

Open AccessArticle

Quebec Spinal Muscular Atrophy Newborn Screening Program: The First Year Experience

by Emilie Groulx-Boivin, Ariane Belzile, Cam-Tu Émilie Nguyen, Amélie Gauthier, Nicolas Chrestian, Catherine Michaud-Gosselin, Yves Giguère, Marie-Thérèse Berthier, Jean-François Soucy, Anne-Marie Laberge and Maryam Oskoui

Int. J. Neonatal Screen. 2025, 11(4), 89; https://doi.org/10.3390/ijns11040089 - 5 Oct 2025

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Abstract

Clinical trials in spinal muscular atrophy (SMA) have shown that early treatment improves outcomes, prompting inclusion in newborn screening (NBS) programs worldwide. The province of Quebec launched its SMA NBS program in October 2023, with a rapidly progressive implementation. We describe the program’s [...] Read more.

Clinical trials in spinal muscular atrophy (SMA) have shown that early treatment improves outcomes, prompting inclusion in newborn screening (NBS) programs worldwide. The province of Quebec launched its SMA NBS program in October 2023, with a rapidly progressive implementation. We describe the program’s first-year experience, focusing on screening yield, birth prevalence, clinical outcomes, and challenges. In the first year, 6 of 67,933 newborns screened positive for SMA, all subsequently confirmed by diagnostic testing. Of these, 4 newborns (67%) had two SMN2 copies and 2 newborns (33%) had four copies. Additionally, one symptomatic compound heterozygote infant presented during this period, indicating a provincial birth prevalence of 1 in 9705 live births (95% CI: 1:20,032–1:4701). Two newborns with two SMN2 copies were symptomatic at initial consultation; one transitioned to palliative care and died at 43 days of life. Surviving newborns initiated treatment at a median age of 30 days (range: 9–103 days), with four receiving onasemnogene abeparvovec and one nusinersen. Motor outcomes at three or six months were stable or improved among treated infants. Overall, the Quebec SMA NBS pilot program successfully identified affected newborns, facilitated early access to therapy, and provided the first provincial estimate of SMA birth prevalence. Improved sample shipping and processing times are needed to maximize the program’s impact, which is expected with full automation. Full article

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22 pages, 1531 KB

Open AccessCommentary

Reflections on 50 Years of Cystic Fibrosis Newborn Screening Experience with Critical Perspectives, Assessment of Current Status, and Predictions for Future Improvements

by Philip M. Farrell

Int. J. Neonatal Screen. 2025, 11(4), 88; https://doi.org/10.3390/ijns11040088 - 30 Sep 2025

Viewed by 198

Abstract

The morbidity/mortality risks of cystic fibrosis (CF) with a delayed diagnosis have made newborn screening (NBS) attractive for the past 50 years. Initial efforts focused on meconium analyses, but these proved unsatisfactory. After dried blood spot specimens became valuable for NBS applied to [...] Read more.

The morbidity/mortality risks of cystic fibrosis (CF) with a delayed diagnosis have made newborn screening (NBS) attractive for the past 50 years. Initial efforts focused on meconium analyses, but these proved unsatisfactory. After dried blood spot specimens became valuable for NBS applied to other genetic disorders and immunoassay methods became routine, the discovery of immunoreactive trypsinogen (IRT) led to numerous CF NBS programs around the world. Excellent laboratorians led the way, but CF clinicians rightly questioned the benefit–risk relationship and unanswered questions about IRT. These issues were resolved by the combination of a positive randomized clinical trial and the discovery of the cystic fibrosis transmembrane conductance regulator gene (CFTR) and its principal pathogenic variant, F508del. Recommendations for universal screening and then the proliferation of IRT/DNA screening programs followed. But more knowledge has brought more complexity, including an enigmatic, distracting condition known as cystic fibrosis transmembrane conductance regulator-related metabolic syndrome (CRMS) or cystic fibrosis screen positive, inconclusive diagnosis (CFSPID). Recently, with the recognition that CF is not a “white person’s disease,” and that over 1000 CFTR pathogenic variants occur, attention has turned to achieving equity and timeliness for all babies. Continuous quality improvement has characterized the past decade, as greatly expanded CFTR panels in the DNA tier through next-generation sequencing offer promise and raise the prospect of a primary genetic screening test. Full article

(This article belongs to the Special Issue Advances in Cystic Fibrosis Newborn Screening: From Laboratory Testing to Diagnosis)

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15 pages, 2219 KB

Open AccessArticle

Evaluating Georgia’s Cystic Fibrosis Newborn Screening Algorithm to Inform Improvement Recommendations

by Brittany Truitt, Eileen Barr, Angela Wittenauer, Andrew Jergel, Shasha Bai, Rossana Sanchez Russo, Kathryn E. Oliver, Kathleen McKie and Rachel W. Linnemann

Int. J. Neonatal Screen. 2025, 11(4), 87; https://doi.org/10.3390/ijns11040087 - 29 Sep 2025

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Abstract

Early diagnosis by newborn screening (NBS) has contributed to improved outcomes in children with cystic fibrosis (CwCF). Georgia’s two-tiered algorithm consists of a fixed immunoreactive trypsinogen (IRT) cut-off followed by a 39-variant CFTR genetic panel. We conducted a retrospective review of CwCF born [...] Read more.

Early diagnosis by newborn screening (NBS) has contributed to improved outcomes in children with cystic fibrosis (CwCF). Georgia’s two-tiered algorithm consists of a fixed immunoreactive trypsinogen (IRT) cut-off followed by a 39-variant CFTR genetic panel. We conducted a retrospective review of CwCF born in Georgia from 2007 to 2022 to evaluate false negative NBS frequency. We characterized CwCF whose diagnosis was delayed beyond 28 days of age despite positive NBS. Six cases were detailed demonstrating the impact of missed and delayed diagnoses. We examined IRT trends from 2018 to 2022 and cut-off approaches. Missed case detection by expanded CFTR variant assays was assessed. Of 390 CwCF born in Georgia, 18 (4.6%) had false negative NBS—6 due to lack of CFTR variant detection and 12 due to low IRT values. Thirty children had delayed diagnosis, with the majority related to sweat testing. Minoritized children made up 19% of the population but 43% of missed and 44% of delayed diagnoses. Black and Hispanic infants had higher odds of missed or delayed diagnosis compared to non-Hispanic White infants (OR = 2.7, p = 0.027 and OR = 6.1, p < 0.001, respectively). Average IRT values varied across kits and were lower in warmer seasons. Expanded CFTR assays would reduce missed cases. Our results informed recommendations for improvement at multiple steps in the NBS process. Full article

(This article belongs to the Special Issue Advances in Cystic Fibrosis Newborn Screening: From Laboratory Testing to Diagnosis)

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19 pages, 632 KB

Open AccessArticle

Medium-Chain Acyl-CoA Dehydrogenase Deficiency (MCADD) Newborn Screening in Italy: Five Years’ Experience from a Nationwide Program

by Margherita Ruoppolo, Cristina Cereda, Teresa Giovanniello, Sabrina Malvagia, Sara Boenzi, Francesca Teofoli, on behalf of the SIMMESN Italian Newborn Screening Group and Alberto Burlina

Int. J. Neonatal Screen. 2025, 11(4), 86; https://doi.org/10.3390/ijns11040086 - 26 Sep 2025

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Abstract

Medium-chain acyl-CoA dehydrogenase deficiency (MCADD) is an autosomal recessive disorder of fatty acid oxidation that can have life-threatening consequences if not promptly treated. Early diagnosis by means of newborn screening (NBS) has the potential to reduce morbidity and mortality. This study investigates the [...] Read more.

Medium-chain acyl-CoA dehydrogenase deficiency (MCADD) is an autosomal recessive disorder of fatty acid oxidation that can have life-threatening consequences if not promptly treated. Early diagnosis by means of newborn screening (NBS) has the potential to reduce morbidity and mortality. This study investigates the incidence and molecular characteristics of MCADD in Italy over a five-year period within the framework of the expanded NBS program. Between January 2019 and December 2023, a total of 1,976,473 newborns were screened. Ninety unrelated neonates were diagnosed with MCADD, providing an estimated incidence of 1/21,960 live births (95% CI: 1:17,780–1:27,200), comparable to rates reported in other Mediterranean populations. Molecular analysis identified c.985A>G (p.Lys329Glu) as the most frequent pathogenic ACADM gene variant, observed in 56 patients (63%), including eighteen patients (20%) who were homozygous and thirty-eight (43%) who were compound heterozygotes for this variant. To our knowledge, this study represents the first comprehensive investigation to document the high prevalence of MCADD among the Italian population. Full article

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14 pages, 3285 KB

Open AccessArticle

CFTR Variant Frequencies and Newborn Screening Panel Performance in the Diverse CF Population Receiving Care in the State of Georgia

by Eileen Barr, Brittany Truitt, Andrew Jergel, Shasha Bai, Kathleen McKie, Rossana Sanchez Russo, Kathryn E. Oliver and Rachel W. Linnemann

Int. J. Neonatal Screen. 2025, 11(4), 85; https://doi.org/10.3390/ijns11040085 - 26 Sep 2025

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Abstract

Cystic fibrosis (CF) newborn screening (NBS) aims to improve outcomes through early diagnosis, yet disparities in time to diagnosis remain. This study examines CFTR allele frequencies and variant panel performance among a diverse CF population in Georgia to inform recommendations for updating the [...] Read more.

Cystic fibrosis (CF) newborn screening (NBS) aims to improve outcomes through early diagnosis, yet disparities in time to diagnosis remain. This study examines CFTR allele frequencies and variant panel performance among a diverse CF population in Georgia to inform recommendations for updating the NBS algorithm and improving equity. This cross-sectional study includes 969 people with CF (PwCF) from Georgia’s accredited CF centers. CFTR variant frequencies were calculated according to race and ethnicity. Panel performance was evaluated for Georgia’s current Luminex-39 variant test and three expanded panels. Statistical analyses compared detection rates across panels and demographic groups. Georgia’s diverse CF population demonstrates a unique CFTR allelic variability compared to national data. Increasing panel size enhances case identification. A panel including 719 CF-causing variants from the CFTR2 database significantly improves case detection from 93% to 97% (p = 0.002), as well as two-variant detection from 69% to 86% (p < 0.001). Detection of minoritized PwCF also improves with increasing panel size. However, even using the 719-variant panel, detection of non-Hispanic Black PwCF remains significantly lower compared to non-Hispanic White PwCF (case detection: p = 0.003; two-variant detection: p < 0.001). In conclusion, the use of expanded CFTR panels for NBS in Georgia would enhance timely diagnosis and improve equity. Full article

(This article belongs to the Special Issue Advances in Cystic Fibrosis Newborn Screening: From Laboratory Testing to Diagnosis)

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19 pages, 1554 KB

Open AccessArticle

Newborn Screening of X-Linked Adrenoleukodystrophy in Italy: Clinical and Biochemical Outcomes from a 4-Year Pilot Study

by Eleonora Bonaventura, Fabio Bruschi, Luisella Alberti, Clara Antonello, Filippo Arrigoni, Marina Balestriero, Barbara Borsani, Laura Cappelletti, Elisa Cattaneo, Matilde Ferrario, Giulia Fiore, Maria Iascone, Giana Izzo, Simona Lucchi, Cecilia Parazzini, Michela Perrone Donnorso, Luigina Spaccini, Ylenia Vaia, Pierangelo Veggiotti, Elvira Verduci, Gianvincenzo Zuccotti, Cristina Cereda, Davide Tonduti and XALD-NBS Study Group Show full author list Hide full author list

Int. J. Neonatal Screen. 2025, 11(4), 84; https://doi.org/10.3390/ijns11040084 - 24 Sep 2025

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Abstract

X-linked adrenoleukodystrophy (X-ALD) is the most common peroxisomal disorder, caused by mutations in the ABCD1 gene. Early diagnosis is critical to manage adrenal insufficiency and cerebral forms of the disease. Since 2021, a pilot newborn screening (NBS) program for X-ALD has been launched [...] Read more.

X-linked adrenoleukodystrophy (X-ALD) is the most common peroxisomal disorder, caused by mutations in the ABCD1 gene. Early diagnosis is critical to manage adrenal insufficiency and cerebral forms of the disease. Since 2021, a pilot newborn screening (NBS) program for X-ALD has been launched in Lombardy, Italy. From September 2021 to June 2025, 138,116 newborns (≥37 weeks’ gestational age) were screened for elevated C26:0-lysophosphatidylcholine (C26:0-LPC) levels using a two-tier algorithm. Genetic testing was performed in non-negative cases. Males found to be ABCD1 variant carriers were enrolled in multidisciplinary follow-up, including neurological, endocrinological, and nutritional assessments. Eleven individuals (six males, five females) carried pathogenic or likely pathogenic ABCD1 variants. Three males were diagnosed with adrenal insufficiency and started hydrocortisone therapy between 1 and 2 years of age. Growth parameters were within normal range overall, but two children showed signs of stunting associated with poor dietary compliance. Additionally, three patients were diagnosed with Zellweger spectrum disorders (ZSDs). No patients affected with Aicardi-Goutières Syndrome were identified. Newborn screening for X-ALD in Italy is feasible and enables early detection and intervention. Biochemical markers and genetic analysis are reliable tools for identifying affected males and female carriers. Multidisciplinary management is essential to address medical and psychosocial challenges during follow-up. Full article

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Int. J. Neonatal Screen., Volume 11, Issue 4 (December 2025) – 11 articles

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