Search Results (39)

The goal of newborn screening (NBS) has remained the same despite its significant expansion from its inception as a public health initiative. This goal is to identify infants that are at risk for a set list of conditions and to implement a care plan to prevent, delay, or mitigate adverse health outcomes for those affected. The role of genetic counselors (GCs) in the NBS space is currently evolving, and there is limited research on parental experiences with genetic counseling for more recently added conditions on a list approved by the U.S. Secretary of Health and Human Services called the Recommended Uniform Screening Panel (RUSP). This qualitative study interviewed parents who have spoken to a genetic counselor after their child was diagnosed with one of three following conditions in the past five years: Pompe disease, X-linked Adrenoleukodystrophy, and Spinal Muscular Atrophy. A total of 13 interviews were conducted and results were organized into five thematic areas: (1) NBS/Results Disclosure, (2) Diagnostic Process after NBS, (3) Treatment/Follow-Up, (4) Communication, and (5) Holistic Support. The findings of this study highlighted parental preferences for early involvement of genetic counselors, provider, and parent education on NBS, and the provision of family support beyond genetic resources. Full article

Pompe disease is an autosomal recessive metabolic disorder caused by acid alpha-glucosidase (GAA) deficiency. The use of umbilical cord blood (UCB) for newborn screening (NBS) of Pompe disease, compared to heel-prick sampling, has not been widely studied. This study compared GAA activity in UCB from term newborns with peripheral or heel-prick blood samples obtained on days 1, 2, and 3 after birth. Enzyme assays were performed using UPLC-MS/MS. Sanger sequencing was conducted in infants with low GAA activity to identify pathogenic variants. Among 4091 UCB samples analyzed over 18 months, the mean GAA activity was 10.04 ± 5.95 μM/h, higher in females than males [Median (IQR): 9.83 (5.45) vs. 9.08 (4.97) μM/h, respectively, p < 0.001], and similar across ethnicities. GAA levels in UCB and Day 3 heel-prick samples were comparable. A GAA cut-off value of 1.54 μM/h (0.1% of study population) identified one infant (0.024% prevalence) with a novel bi-allelic variant—c.2005_2010del (p.Pro669_Phe670del) and c.1123C>T (p.Arg375Cys), and 12 infants with non-pathogenic pseudodeficiency alleles. This study supports GAA measurement in UCB as a viable alternative for NBS, with enzyme activity remaining stable for up to 72 h post-collection. Larger-scale multicenter nationwide studies are warranted to confirm this prevalence in our population. Full article

Newborn screening laboratories are increasingly adding lysosomal storage disorders (LSDs), such as Mucopolysaccharidosis I (MPS I) and Pompe disease, to their screening panels. Without newborn screening, LSDs are frequently diagnosed only after the onset of symptoms; late detection can lead to profound and irreversible organ damage and mortality. While screening of these disorders has accelerated over the past five years, there is little published information regarding the potential correlation of demographic variables (age at sample collection, birthweight, gestational age, gender, etc.) with lysosomal enzyme activity. The Missouri State Public Health Laboratory prospectively screened more than 475,000 newborns for MPS I, Pompe disease, Gaucher disease, and Fabry disease between 15 January 2013 and 15 May 2018. This report investigates trends between several demographic variables and activities of four lysosomal enzymes: α-L-iduronidase (IDUA), acid α-glucosidase (GAA), acid β-glucocerebrosidase (GBA), and acid α-galactosidase (GLA). This information provides a valuable resource to newborn screening laboratories for the implementation of screening for lysosomal storage disorders and the establishment of screening cutoffs. Full article

Newborn screening (NBS) is leading to the diagnosis of a large number of children with late-onset Pompe disease (LOPD), yet many remain asymptomatic until later years. A high-protein, low-carbohydrate diet is recommended for adults with LOPD. Nutrition guidelines are not available for young children. Methods: 37 children with LOPD aged 1–6 years participated. Early diet history, feeding practices, and 24 h dietary intake were collected via questionnaire. Anthropometric measurements, blood creatine kinase (CK), blood urea nitrogen (BUN)/creatinine ratio, and urine glucose tetrasaccharide (Glc4) were collected at clinic visits. A subset of 19 children received a clinical feeding assessment (CFA). Results: All patients derived their nutrition orally. Breastfeeding was successfully initiated in 73% of infants. Body weight ranged between 3 and 99% and height ranged from 4 to 97%. A tendency to be overweight and obese was noted in older children with LOPD. A total of 24% of the children who had CFA were diagnosed with dysphagia that was typically mild in severity and rarely affected their ability to eat a normal diet. Limiting added sugar and processed foods was the most widely used dietary practice followed by encouraging protein. Protein intake was three–four times higher than the recommended dietary intake (RDA). A high BUN/creatinine ratio was observed in some children, which may indicate incompatibility with protein intake and need for individualizing the diet. Conclusions: The results of this study provide a framework for developing future nutrition guidelines for children with LOPD by performing an individualized assessment of dietary intake, growth, feeding/swallowing, and laboratory parameters. Full article

Pennsylvania started newborn screening for Pompe disease (PD) in 2016. As a result, the prevalence of PD has increased with early detection, primarily of late-onset Pompe disease (LOPD). No clear guidelines exist regarding if and when to initiate enzyme replacement therapy (ERT) in patients identified through a newborn screen (NBS). To help define the natural history and indications for starting ERT, we present the long-term follow-up data of 45 patients identified through NBS from 2016 to 2021. These patients were evaluated at regular intervals through our multi-disciplinary clinic at the Children’s Hospital of Philadelphia (CHOP) with physical examinations, physical therapy evaluations, muscle biomarkers including creatine kinase (CK), aspartate aminotransferase (AST), alanine aminotransferase (ALT), and hexosaminidase 4 levels (Hex4), as well as cardiac evaluation at certain points in time. We found that newborn screening of acid alpha-glucosidase (GAA) enzyme detected primarily LOPD. One case of infantile-onset PD (IOPD) was detected. Muscle biomarkers in LOPD were elevated at birth and showed a general downward trend over time. NBS GAA levels and initial CK levels helped to differentiate LOPD cases from unaffected infants (carriers, pseudodeficiency alleles), while Hex4 was not a meaningful discriminator. On repeat NBS, there was a significant difference between mean GAA levels for the unaffected vs. compound heterozygote groups and unaffected vs. homozygote groups for the common splice site pathogenic variant (c.-32-13T>G). Echocardiogram and electrocardiogram (EKG) are essentially normal at the first evaluation in LOPD. One LOPD patient was started on ERT at age 4.5 months. Continued data collection on these patients is critical for developing management guidelines, including timing of ERT and improved genotype–phenotype correlation. Full article

Newborn screening (NBS) presents an opportunity to identify a subset of babies at birth who are at risk for developmental delays and could benefit from a range of developmental services. Potential developmental services in the United States include Part C Early Intervention (EI), private therapies, and school-based services. Using parent-reported outcomes, this study examined the rates at which a sample of children diagnosed with NBS conditions used each developmental service. An online survey of 153 parents representing children with 27 different NBS conditions found that nearly 75% of children (n = 112) used at least one developmental service, with private therapies being the most frequent. Children were referred to EI relatively early and were often eligible because their medical diagnosis automatically qualified them. When examining condition-specific results for children with severe combined immunodeficiencies, congenital hypothyroidism, and Pompe disease, we found variability in rates of use, with high rates overall. Our findings suggest that many children diagnosed with an NBS condition continue to have developmental delays even after they receive appropriate medical care. Future research with more systematic follow-up is needed to understand whether the NBS program facilitates entry into these services and whether more streamlined processes could benefit children and families. Full article

In the last two decades, the development of high-throughput diagnostic methods and the availability of effective treatments have increased the interest in newborn screening for lysosomal storage disorders. However, long-term follow-up experience is needed to clearly identify risks, benefits and challenges. We report our 8-year experience of screening and follow-up on about 250,000 neonates screened for four lysosomal storage diseases (Pompe disease, mucopolysaccharidosis type I, Fabry disease, Gaucher disease), using the enzyme activity assay by tandem mass spectrometry, and biomarker quantification as a second-tier test. Among the 126 positive newborns (0.051%), 51 infants were confirmed as affected (positive predictive value 40%), with an overall incidence of 1:4874. Of these, three patients with infantile-onset Pompe disease, two with neonatal-onset Gaucher disease and four with mucopolysaccharidosis type I were immediately treated. Furthermore, another four Gaucher disease patients needed treatment in the first years of life. Our study demonstrates the feasibility and effectiveness of newborn screening for lysosomal storage diseases. Early diagnosis and treatment allow the achievement of better patient outcomes. Challenges such as false-positive rates, the diagnosis of variants of uncertain significance or late-onset forms and the lack of treatment for neuronopathic forms, should be addressed. Full article

Lysosomal storage disorders (LSDs) constitute a large group of rare, multisystemic, inherited disorders of metabolism, characterized by defects in lysosomal enzymes, accessory proteins, membrane transporters or trafficking proteins. Pompe disease (PD) is produced by mutations in the acid alpha-glucosidase (GAA) lysosomal enzyme. This enzymatic deficiency leads to the aberrant accumulation of glycogen in the lysosome. The onset of symptoms, including a variety of neurological and multiple-organ pathologies, can range from birth to adulthood, and disease severity can vary between individuals. Although very significant advances related to the development of new treatments, and also to the improvement of newborn screening programs and tools for a more accurate diagnosis and follow-up of patients, have occurred over recent years, there exists an unmet need for further understanding the molecular mechanisms underlying the progression of the disease. Also, the reason why currently available treatments lose effectiveness over time in some patients is not completely understood. In this scenario, characterization of the metabolic phenotype is a valuable approach to gain insights into the global impact of lysosomal dysfunction, and its potential correlation with clinical progression and response to therapies. These approaches represent a discovery tool for investigating disease-induced modifications in the complete metabolic profile, including large numbers of metabolites that are simultaneously analyzed, enabling the identification of novel potential biomarkers associated with these conditions. This review aims to highlight the most relevant findings of recently published omics-based studies with a particular focus on describing the clinical potential of the specific metabolic phenotypes associated to different subgroups of PD patients. Full article

Metabolic myopathies are rare inherited disorders that deserve more attention from neurologists and pediatricians. Pompe disease and McArdle disease represent some of the most common diseases in clinical practice; however, other less common diseases are now better-known. In general the pathophysiology of metabolic myopathies needs to be better understood. Thanks to the advent of next-generation sequencing (NGS), genetic testing has replaced more invasive investigations and sophisticated enzymatic assays to reach a final diagnosis in many cases. The current diagnostic algorithms for metabolic myopathies have integrated this paradigm shift and restrict invasive investigations for complicated cases. Moreover, NGS contributes to the discovery of novel genes and proteins, providing new insights into muscle metabolism and pathophysiology. More importantly, a growing number of these conditions are amenable to therapeutic approaches such as diets of different kinds, exercise training protocols, and enzyme replacement therapy or gene therapy. Prevention and management—notably of rhabdomyolysis—are key to avoiding serious and potentially life-threatening complications and improving patients’ quality of life. Although not devoid of limitations, the newborn screening programs that are currently mushrooming across the globe show that early intervention in metabolic myopathies is a key factor for better therapeutic efficacy and long-term prognosis. As a whole NGS has largely increased the diagnostic yield of metabolic myopathies, but more invasive but classical investigations are still critical when the genetic diagnosis is unclear or when it comes to optimizing the follow-up and care of these muscular disorders. Full article

The Recommended Uniform Screening Panel (RUSP) is the list of conditions recommended by the US Secretary of Health and Human Services for inclusion in state newborn screening (NBS). During 2010–2022, seven conditions were added to the RUSP: severe combined immunodeficiency (SCID) (2010), critical congenital heart disease (CCHD) (2011), glycogen storage disease, type II (Pompe) (2015), mucopolysaccharidosis, type I (MPS I) (2016), X-linked adrenoleukodystrophy (X-ALD) (2016), spinal muscular atrophy (SMA) (2018), and mucopolysaccharidosis, type II (MPS II) (2022). The adoption of SCID and CCHD newborn screening by programs in all 50 states and three territories (Washington, D.C.; Guam; and Puerto Rico) took 8.6 and 6.8 years, respectively. As of December 2022, 37 programs screen for Pompe, 34 for MPS I, 32 for X-ALD, and 48 for SMA. The pace of implementation based on the average additional number of NBS programs per year was most rapid for SMA (11.3), followed by CCHD (7.8), SCID (6.2), MPS I (5.4), Pompe (4.9), and X-ALD (4.7). Full article

In newborn screening, false-negative results can be disastrous, leading to disability and death, while false-positive results contribute to parental anxiety and unnecessary follow-ups. Cutoffs are set conservatively to prevent missed cases for Pompe and MPS I, resulting in increased falsepositive results and lower positive predictive values. Harmonization has been proposed as a way to minimize false-negative and false-positive results and correct for method differences, so we harmonized enzyme activities for Pompe and MPS I across laboratories and testing methods (Tandem Mass Spectrometry (MS/MS) or Digital Microfluidics (DMF)). Participating states analyzed proofof- concept calibrators, blanks, and contrived specimens and reported enzyme activities, cutoffs, and other testing parameters to Tennessee. Regression and multiples of the median were used to harmonize the data. We observed varied cutoffs and results. Six of seven MS/MS labs reported enzyme activities for one specimen for MPS I marginally above their respective cutoffs with results classified as negative, whereas all DMF labs reported this specimen’s enzyme activity below their respective cutoffs with results classified as positive. Reasonable agreement in enzyme activities and cutoffs was achieved with harmonization; however, harmonization does not change how a value would be reported as this is dependent on the placement of cutoffs. Full article

In recent years, there has been a significant increase in the diagnosis of asymptomatic Late-Onset Pompe Disease (LOPD) patients, who are detected via family screening or Newborn Screening (NBS). The dilemma is when to start Enzyme Replacement Therapy (ERT) in patients without any clinical sign of the disease, considering its important benefits in terms of loss of muscle but also its very high cost, risk of side effects, and long-term immunogenicity. Muscle Magnetic Resonance Imaging (MRI) is accessible, radiation-free, and reproducible; therefore, it is an important instrument for the diagnosis and follow-up of patients with LOPD, especially in asymptomatic cases. European guidelines suggest monitoring in asymptomatic LOPD cases with minimal MRI findings, although other guidelines consider starting ERT in apparently asymptomatic cases with initial muscle involvement (e.g., paraspinal muscles). We describe three siblings affected by LOPD who present compound heterozygosis and wide phenotypic variability. The three cases differ in age at presentation, symptoms, urinary tetrasaccharide levels, and MRI findings, confirming the significant phenotypic variability of LOPD and the difficulty in deciding when to start therapy. Full article

The mucopolysaccharidoses (MPS), Pompe Disease (PD), and Krabbe disease (KD) are inherited conditions known as lysosomal storage disorders (LSDs) The resulting enzyme deficiencies give rise to progressive symptoms. The United States Department of Health and Human Services’ Recommended Uniform Screening Panel (RUSP) suggests LSDs for inclusion in state universal newborn screening (NBS) programs and has identified screening deficiencies in MPS I, KD, and PD NBS programs. MPS I NBS programs utilize newborn dried blood spots and assay alpha L-iduronidase (IDUA) enzyme to screen for potential cases. Glycosaminoglycans (GAGs) offer potential as a confirmatory test. KD NBS programs utilize galactocerebrosidase (GaLC) as an initial test, with psychosine (PSY) activity increasingly used as a confirmatory test for predicting onset of Krabbe disease, though with an excessive false positive rate. PD is marked by a deficiency in acid α-glucosidase (GAA), causing increased glycogen, creatine (CRE), and other biomarkers. Bivariate normal limit (BVNL) methods have been applied to GaLC and PSY activity to produce a NBS tool for KD, and more recently, to IDUA and GAG activity to develop a NBS tool for MPS I. A BVNL tool based on GAA and CRE is in development for infantile PD diagnosis. Early infantile KD, MPS I, and PD cases were pre-symptomatically identified by BVNL-based NBS tools. This article reviews these developments, discusses how they address screening deficiencies identified by the RUSP and may improve NBS more generally. Full article

Newborn screening was established over 50 years ago to identify cases of disorders that were serious, urgent, and treatable, mirroring the criteria of Wilson and Jungner. In the last decade, conditions have been added to newborn screening that do not strictly meet these criteria, and genomic newborn screening is beginning to be discussed. Some of these new and proposed additions to newborn screening entail serious public health ethical issues that need to be explored. Full article

Pompe disease (PD) is an inherited metabolic disorder caused by a deficiency of acid α-glucosidase (GAA), leading to lysosomal accumulation of glycogen, mainly in skeletal and cardiac muscles as well as the nervous system. Patients with PD develop cellular dysfunction and muscle damage. PD can be classified into two classic forms, namely infantile-onset PD (IOPD) and late-onset PD (LOPD). Delayed treatment, particularly in IOPD, would result in significant organ damage and early death. Nonetheless, early diagnosis and timely treatment are often hampered by the rarity of PD and its wide variety of, but overlapping, symptoms. This article reviews the common clinical presentations of PD and outlines the essentials of PD management. In particular, the implications of newborn screening (NBS) and clinical performance of enzyme replacement therapy (ERT) are highlighted. Full article