Improving newborn screening in India: Disease gaps and quality control

In India, newborn screening (NBS) is essential for detecting health problems in infants. Despite significant progress, significant gaps and challenges persist. India has made great strides in genomics dueto the existence of the National Institute of Biomedical Genomics in West Bengal. The work emphasizes the challenges NBS programs confront with technology, budgetary constraints, insufficient counseling, inequality in illness panels, and a lack of awareness. Advancements in technology, such as genetic testing and next-generation sequencing, are expected to significantly transform the process. The integration of analytical tools, artificial intelligence, and machine learning algorithms could improve the efficiency of newborn screening programs, offering a personalized healthcare approach. It is critical to address gaps in information, inequities in illness incidence, budgetary restrictions, and inadequate counseling. Strengthening national NBS programs requires increased public awareness and coordinated efforts between state and central agencies. Quality control procedures must be used at every level for implementation to be successful. Additional studies endeavor to enhance NBS in India through public education, illness screening expansion, enhanced quality control, government incentive implementation, partnership promotion, and expert training. Improved neonatal health outcomes and the viability of the program across the country will depend heavily on new technology and counseling techniques.

Diagnostic Accuracy of Creatine Kinase Isoenzyme-MM Test in Newborn Screening for Duchenne Muscular Dystrophy: A Systematic Review and Meta-Analysis

BACKGROUND

To systematically evaluate the diagnostic accuracy of the creatine kinase isoenzyme-MM (CK-MM) test in newborn screening for Duchenne muscular dystrophy (DMD).

METHODS

A comprehensive literature search was conducted up to October 31, 2022, in PubMed, Embase, Cochrane Library, Web of Science, and Scopus Database. To evaluate the diagnostic value, the sensitivity (SEN), specificity (SPE), positive likelihood ratio (PLR), negative likelihood ratio (NLR), diagnostic odds ratio (DOR), area under the curve (AUC), and Q∗ index were pooled. Threshold effect followed by subgroup analysis and meta-regression were performed to explore the source of heterogeneity. Sensitivity analysis was used to verify the robustness of the findings.

RESULTS

A total seven studies with 248,853 newborns was included in our meta-analysis. The pooled SEN and SPE were 1.00 (95% confidence interval [CI]: 0.89∼1.00) and 1.00 (95% CI: 1.00 to 1.00), respectively; the PLR and NLR were 1004.59 (95% CI: 251.37∼4014.91) and 0.13 (95% CI: 0.05∼0.34), respectively; the DOR was 877.96 (95% CI: 983.24∼78,366.32); the AUC and Q index were 0.8683 and 0.9326, respectively. Sensitivity analysis showed that two studies had an impact on the pooled results and mainly contributed to the heterogeneity.

CONCLUSIONS

CK-MM test demonstrated high accuracy in newborn screening for DMD and may be a valuable alternative in the early diagnosis of the disease followed by confirmatory genetic testing.

The treatment of biochemical genetic diseases: From substrate reduction to nucleic acid therapies

Newborn screening (NBS) began a revolution in the management of biochemical genetic diseases, greatly increasing the number of patients for whom dietary therapy would be beneficial in preventing complications in phenylketonuria as well as in a few similar disorders. The advent of next generation sequencing and expansion of NBS have markedly increased the number of biochemical genetic diseases as well as the number of patients identified each year. With the avalanche of new and proposed therapies, a second wave of options for the treatment of biochemical genetic disorders has emerged. These therapies range from simple substrate reduction to enzyme replacement, and now ex vivo gene therapy with autologous cell transplantation. In some instances, it may be optimal to introduce nucleic acid therapy during the prenatal period to avoid fetopathy. However, as with any new therapy, complications may occur. It is important for physicians and other caregivers, along with ethicists, to determine what new therapies might be beneficial to the patient, and which therapies have to be avoided for those individuals who have less severe problems and for which standard treatments are available. The purpose of this review is to discuss the "Standard" treatment plans that have been in place for many years and to identify the newest and upcoming therapies, to assist the physician and other healthcare workers in making the right decisions regarding the initiation of both the "Standard" and new therapies. We have utilized several diseases to illustrate the applications of these different modalities and discussed for which disorders they may be suitable. The future is bright, but optimal care of the patient, including and especially the newborn infant, requires a deep knowledge of the disease process and careful consideration of the necessary treatment plan, not just based on the different genetic defects but also with regards to different variants within a gene itself.

Natural history of infants with non-SCID T cell lymphopenia identified on newborn screen

Newborn screening (NBS) for severe combined immunodeficiency (SCID) can identify infants with non-SCID T cell lymphopenia (TCL). The purpose of this study was to characterize the natural history and genetic findings of infants with non-SCID TCL identified on NBS. We analyzed data from 80 infants with non-SCID TCL in the mid-Atlantic region between 2012 and 2019. 66 patients underwent genetic testing and 41 (51%) had identified genetic variant(s). The most common genetic variants were thymic defects (33%), defects with unknown mechanisms (12%) and bone marrow production defects (5%). The genetic cohort had significantly lower median initial CD3+, CD4+, CD8+ and CD4/CD45RA+ T cell counts compared to the non-genetic cohort. Thirty-six (45%) had either viral, bacterial, or fungal infection; only one patient had an opportunistic infection (vaccine strain VZV infection). Twenty-six (31%) of patients had resolution of TCL during the study period.

Does newborn screening improve early lung function in cystic fibrosis?

Despite evidence showing an improvement in nutritional outcomes following diagnosis by newborn screening (NBS) for cystic fibrosis (CF), the impact on pulmonary outcomes has been less clear. In this review the approaches to measurement of early lung function and knowledge gained from NBS CF cohorts will be described. Studies which have compared outcomes in those diagnosed by NBS to those diagnosed following symptomatic presentation will be presented. Compiling the evidence base used to evaluate the impact of NBS on pulmonary outcomes has been complicated by improvements in clinical management, infection control practices, as well as public health interventions (such as tobacco smoking bans in public places) that have evolved substantially over recent decades. Forced expiratory volumes have been used as the main outcome but it is important not to draw conclusions for 'early lung function' from tests such as spirometry alone, which lack sensitivity in early lung disease. There is, at present, insufficient evidence to draw firm conclusions about the effect of NBS on early lung function. In an era of highly effective treatments targeting the underlying molecular defect responsible for CF, future opportunities for early initiation of treatment may mean that the impact of NBS on early lung function may yet to be realised.

Spontaneous resolution of severe idiopathic T cell lymphopenia

Potential etiologies of T-B + NK+ SCID include both hematopoietic defects and thymic aplasia. The management of patients with this phenotype, identified by newborn screen, may be unclear in the absence of a genetic diagnosis. We report an infant with lymphocyte flow cytometry consistent with T-B + NK+ SCID and reduced proliferative response to phytohemagglutinin. The patient had no genetic diagnosis after targeted panel and exome sequencing. The decision to trend laboratory values rather than move immediately to hematopoietic cell transplant was made given the absence of a genetic defect and the finding of a normal thymus on ultrasound. During the course of evaluation for transplant, the patient unexpectedly had normalization of T cell number and function. This case demonstrates a role for mediastinal ultrasound and the utility of trending laboratory values in patients with severe T cell lymphopenia but no genetic diagnosis, given the small but important possibility of spontaneous resolution.

Final results of the southwest German pilot study on cystic fibrosis newborn screening - Evaluation of an IRT/PAP protocol with IRT-dependent safety net: Results of the Southwest German CFNBS pilot study

BACKGROUND

Previous studies suggest that PAP-based CF protocols are suitable for newborn screening (NBS) for cystic fibrosis (CF) when newborns designated as CFSPID should not be detected. However, there are still discussions about the performance of IRT/PAP algorithms. We present the final results of a pilot study evaluating a IRT/PAP protocol with an IRT-dependent safety net (SN) conducted from 2008 to 2016 in southwestern Germany on nearly 500,000 newborns.

METHODS

To achieve reliable data, all newborns were screened using both the PAP-based and a DNA-based CFNBS algorithm. PAP quantification and genetic analysis of the four most common CFTR mutations in Germany were performed in all newborns with IRT≥99.0 percentile. NBS was rated positive if either PAP was ≥1.6 µg/l and/or at least one CFTR mutation was detected. In addition, an IRT-dependent SN resulted in positive rating for both protocols if IRT was ≥99.9 percentile. To evaluate the IRT/PAP protocol, its performance was compared to that of the IRT/DNA protocol.

RESULTS

The IRT/PAP protocol with IRT-based SN used in the study achieved a sensitivity of 94%, if false-negative detected neonates with meconium ileus and those designated as CFSPID were excluded from analysis. CF/CFSPID ratio was 92. However, PPV of the IRT/PAP+SN protocol was with 10.3% very low.

CONCLUSIONS

PAP-based CFNBS protocols can be used, if less detection of CFSPID is desired. The IRT/PAP protocol with IRT-dependent SN evaluated here achieved adequate sensitivity but should probably be used in combination with a third-tier test to also achieve an acceptable PPV.

Newborn Screening for Severe Combined Immunodeficiency

The T-cell receptor excision circle (TREC) assay is an effective screening tool for severe combined immunodeficiency (SCID). The TREC assay was designed to detect typical SCID and leaky SCID, but any condition causing low naïve T-cell counts will also be detected. Newborn screening for SCID using the TREC assay has proven itself to be highly sensitive and cost-efficient. This review covers the history of SCID newborn screening, elaborates on the SCID subtypes and TREC assay limitations, and discusses diagnostic and management considerations for infants with a positive screen.

Two Years of Newborn Screening for Cystic Fibrosis in North Macedonia: First Experience

There is a widely accepted consensus on the benefits of newborn screening (NBS) for cystic fibrosis (CF) in terms of reduced disease severity, improved quality of life, lower treatment burden, and reduced costs. More and more countries in the world are introducing NBS for CF as a national preventive health program. Newborn screening for CF was introduced in the Republic of North Macedonia (RNM) in April, 2019, after a pilot study of 6 months in 2018. A two-step immunoreactive trysinogen (IRT-IRT) algorithm is performed, and then a sweat test for confirmation/exclusion of the CF diagnosis when the IRT values were both over the cutoff (70.0 and 45.0 ng/mL, respectively). In cases with confirmed diagnosis of CF (a sweat chloride concentration >60.0 mmol/L) or with intermediate sweat test results (a sweat chloride concentration of between 30.0 and 59.0 mmol/L), CF transmembrane conductance regulator (CFTR) mutation analysis is performed. By the end of 2020, over a period of 27 months, including the pilot study period, a total number of 43,139 newborns were screened for CF. Seventeen (0.039%) newborns were diagnosed with CF. In all newly discovered CF cases by screening, the diagnosis was confirmed by determination of the CFTR mutations. The most common CFTR mutation, F508del, was found with an overall incidence of 70.6%. Other more frequent mutations were G542X (11.8%) and N1303K (5.9%). Four mutations were found in one CFTR allele each: G1349D, G126D, 457TAT>G and CFTRdupexon22, with the last one being newly discovered with unknown consequences. An incredibly large difference was found in the incidence of the disease between the Macedonian and Albanian neonatal population, with almost four time higher prevalence among Albanians (1:4530 vs. 1:1284).

Ten Years of Newborn Screening for Severe Combined Immunodeficiency (SCID) in Massachusetts

BACKGROUND

Massachusetts began newborn screening (NBS) for severe combined immunodeficiency (SCID) using measurement of T-cell receptor excision circles (TRECs) from dried blood spots.

OBJECTIVE

We describe developments and outcomes from the first 10 years of this program (February 1, 2009, to January 31, 2019).

METHODS

TREC values, diagnostic, and outcome data from all patients screened for SCID were evaluated.

RESULTS

NBS of 720,038 infants prompted immunologic evaluation of 237 (0.03%). Of 237, 9 were diagnosed with SCID/leaky SCID (4% of referrals vs 0.001% general population). Another 7 were diagnosed with other combined immunodeficiencies, and 3 with athymia. SCID/leaky SCID incidence was approximately 1 in 80,000, whereas approximately 1 in 51,000 had severe T-cell lymphopenia for which definitive treatment was indicated. All patients with SCID/leaky SCID underwent hematopoietic cell transplant or gene therapy with 100% survival. One patient with athymia underwent successful thymus transplant. No known cases of SCID were missed. Compared with outcomes from the 10 years before SCID NBS, survival trended higher (9 of 9 vs 4 of 7), likely due to a lower rate of infection before treatment.

CONCLUSIONS

Our data support a single NBS testing-and-referral algorithm for all gestational ages. Despite lower median TREC values in premature infants, the majority for all ages are well above the TREC cutoff and the algorithm, which selects urgent (undetectable TREC) and repeatedly abnormal TREC values, minimizes referral. We also found that low naïve T-cell percentage is associated with a higher risk of SCID/CID, demonstrating the utility of memory/naïve T-cell phenotyping as part of follow-up flow cytometry.

Newborn Screening for Severe Combined Immunodeficiency

The T-cell receptor excision circle (TREC) assay is an effective screening tool for severe combined immunodeficiency (SCID). The TREC assay was designed to detect typical SCID and leaky SCID, but any condition causing low naïve T-cell counts will also be detected. Newborn screening for SCID using the TREC assay has proven itself to be highly sensitive and cost-efficient. This review covers the history of SCID newborn screening, elaborates on the SCID subtypes and TREC assay limitations, and discusses diagnostic and management considerations for infants with a positive screen.

Newborn screening and changing face of inborn errors of metabolism in the United States

Newborn screening (NBS) in the United States helps each year diagnose, 1 in every 320 newborns (12,500 of the 4 million births), with a potentially severe or lethal condition prior to clinical symptoms manifestation. 10% of these are inborn errors of metabolism (IEM). Coordinated efforts of NBS program, primary care physicians, and metabolic centers can help with pre-symptomatic identification and interventions for such conditions to ameliorate or resolve associated morbidity and mortality. NBS in the United States is a successful public health program to improve short and long term health outcomes for newborns. Federal and State agencies provide the regulatory and funding framework to implement NBS programs, while professional societies provide medical guidelines to help identify and manage such conditions. However, each State independently organizes and administers its own NBS program. This article reviews the common NBS program workflow, federal regulatory framework, uniform screening panel recommendations, the testing processes and ethical considerations involved.

Tandem mass spectrometry assay of β-glucocerebrosidase activity in dried blood spots eliminates false positives detected in fluorescence assay

Deficiency of β-Glucocerebrosidase (GBA) activity causes Gaucher Disease (GD). GD can be diagnosed by measuring GBA activity (Beutler and Kuhl, 1990). In this study, we assayed dried blood spots from a cohort (n=528) enriched for GBA mutation carriers (n=78) and GD patients (n=18) using both the tandem mass spectrometry (MS/MS) and fluorescence assays and their respective synthetic substrates. The MS/MS assay differentiated normal controls, which included GBA mutation carriers, from GD patients with no overlap. The fluorescence assay did not always differentiate normal controls including GBA mutation carriers from GD patients and false positives were observed. The MS/MS assay improved specificity compared to the fluorescence assay.

Leigh-Like Syndrome Due to Homoplasmic m.8993T>G Variant with Hypocitrullinemia and Unusual Biochemical Features Suggestive of Multiple Carboxylase Deficiency (MCD)

Leigh syndrome (LS), or subacute necrotizing encephalomyelopathy, is a genetically heterogeneous, relentlessly progressive, devastating neurodegenerative disorder that usually presents in infancy or early childhood. A diagnosis of Leigh-like syndrome may be considered in individuals who do not fulfil the stringent diagnostic criteria but have features resembling Leigh syndrome.We describe a unique presentation of Leigh-like syndrome in a 3-year-old boy with elevated 3-hydroxyisovalerylcarnitine (C5-OH) on newborn screening (NBS). Subsequent persistent plasma elevations of C5-OH and propionylcarnitine (C3) as well as fluctuating urinary markers were suggestive of multiple carboxylase deficiency (MCD). Normal enzymology and mutational analysis of genes encoding holocarboxylase synthetase (HLCS) and biotinidase (BTD) excluded MCD. Biotin uptake studies were normal excluding biotin transporter deficiency. His clinical features at 13 months of age comprised psychomotor delay, central hypotonia, myopathy, failure to thrive, hypocitrullinemia, recurrent episodes of decompensation with metabolic keto-lactic acidosis and an episode of hyperammonemia. Biotin treatment from 13 months of age was associated with increased patient activity, alertness, and attainment of new developmental milestones, despite lack of biochemical improvements. Whole exome sequencing (WES) analysis failed to identify any other variants which could likely contribute to the observed phenotype, apart from the homoplasmic (100%) m.8993T>G variant initially detected by mitochondrial DNA (mtDNA) sequencing.Hypocitrullinemia has been reported in patients with the m.8993T>G variant and other mitochondrial disorders. However, persistent plasma elevations of C3 and C5-OH have previously only been reported in one other patient with this homoplasmic mutation. We suggest considering the m.8993T>G variant early in the diagnostic evaluation of MCD-like biochemical disturbances, particularly when associated with hypocitrullinemia on NBS and subsequent confirmatory tests. An oral biotin trial is also warranted.

Newborn screening for SCID: lessons learned

INTRODUCTION

Newborn screening (NBS) for Severe combined immunodeficiency (SCID)/severe T cell lymphopenia (sTCL) is being increasingly used worldwide.

AREAS COVERED

In this manuscript we will discuss the following: 1) The rationale for screening newborns for SCID/sTCL; 2) The scientific basis for the use of the T cell receptor excision circle (TREC) assay in screening newborns for SCID/sTCL; 3) The published outcomes of current NBS programs. Expert commentary: 4) Some of the ethical dilemmas that occur when screening newborns for SCID. Finally, we will discuss the future directions for expanding NBS to include other primary immunodeficiencies.

Screening for and treatments of congenital immunodeficiency diseases

Although newborn screening (NBS) for inborn errors of metabolism has been successfully utilized in the US for decades, only recently has this screening program expanded to include disorders of immunity. Severe combined immunodeficiency (SCID) became the first disorder of immunity to be screened on a population wide basis in 2008. While NBS for SCID has been successful, the implementation of population-based screening programs is not without controversy, and there remain barriers to the nationwide implementation of this test. In addition, as the program has progressed we have learned of new challenges in the management of newborns that fail this screen.

Preliminary investigation of the use of newborn dried blood spots for screening pyridoxine-dependent epilepsy by LC-MS/MS

α-AASA and P6C were measured retrospectively in original newborn DBS of five patients with PDE using a LC-MS/MS method we developed previously. Both α-AASA and P6C were elevated markedly in the three newborn DBS stored at -20°C. At room temperature, α-AASA and P6C in DBS appeared stable for 3 days and then decreased by up to 70% after 14 days but remained much higher than control, indicating newborn screening for PDE is feasible.