Two years of newborn screening for Duchenne muscular dystrophy as a part of the statewide Early Check research program in North Carolina

Quantification and comparison of anti-AAV9 and anti-AAVrh74 antibodies in plasma and human milk: Implications for AAV-based gene therapy candidacy

BackgroundThe application of recombinant adeno associated virus (rAAV) in gene therapy is accepted as an effective strategy for the treatment of monogenic diseases. However, eligibility for such therapies is contingent upon the absence or minimal presence of antibodies against adeno-associated virus (AAV) capsid protein. While the passive transfer of maternal immunoglobulins in utero is well established, the potential impact of maternal antibodies transferred via breastfeeding remains less explored.ObjectiveThis study aims to quantify and compare the levels of anti-AAV9 and anti-AAVrh74 immunoglobulin G (IgG) and M (IgM) in both plasma and human milk from a group of healthy lactating mothers.MethodsIn this cross-sectional study, we analyzed plasma and human milk samples from healthy lactating mothers. We used an enzyme linked immunosorbent assay (ELISA) to determine the levels of circulating IgG and IgM antibodies against AAV9 and AAVrh74 capsids and compared their concentrations in the paired samples.ResultsThirty-one paired plasma and human milk samples were analyzed. The median age at participation was 34 years (range: 25-43), median duration of breastfeeding at the time of sample collection was 7.5 months (range:0.7-33), and median body mass index was 23 Kg/m2 (range: 19.7-35.4). Median anti-AAV9 IgG in plasma and human milk, were 183 U/mL (range: 29-7214) and 1 U/mL (range: 1-33), respectively. Median anti-AAVrh74 IgG, in plasma and human milk were 138 U/mL (range: 23-8725) and 1 U/mL (range: 1-27), respectively. The differences in anti-AAV9 and anti-AAVrh74 IgG levels between plasma and human milk were statistically significant (p < 0.0001). Additionally, a strong correlation (r: 0.97, p: < 0.0001) was observed between anti-AAV9 and anti-AAVrh74 IgG levels in plasma.ConclusionsThe levels of anti-AAV9 and anti-AAVrh74 antibodies in human milk are remarkably lower than those in plasma. Consequently, breastfeeding should not be restricted for term infants who are potential candidates for AAV-related gene therapy products.

Newborn screening and rapid genomic diagnosis of neuromuscular diseases

BackgroundIn recent years, treatments have been approved for certain neuromuscular diseases. In some cases, early pre-symptomatic treatment is necessary for optimal response, and thus newborn screening is critical.ObjectiveTo review the current status of newborn screening programs for neuromuscular diseases and early diagnosis through genetic testing.MethodsFollowing the PRISMA guidelines, a literature search was performed on PubMed for screening of neuromuscular diseases; the search was conducted on literature available as of 1 May 2024.ResultsIncluded were 77 articles on newborn screening for seven diseases: spinal muscular atrophy (19 studies), Duchenne muscular dystrophy (15), Pompe disease (20), X-linked adrenoleukodystrophy (14), Krabbe disease (6), metachromatic leukodystrophy (2), and myotonic dystrophy 1 (1). Ten articles on rapid genomic diagnosis were identified.ConclusionSince 2021, newborn screening programs for neuromuscular diseases have been established, notably in X-linked adrenoleukodystrophy, spinal muscular atrophy, Pompe disease, and Duchenne Muscular Dystrophy. Even in diseases where treatment is currently not life-changing, such as Krabbe disease, new newborn screening programs continue to be implemented, especially in the USA. The use of genetic diagnostic tests does not yet appear to be widespread or at least not widely reported. As new treatments become available, genomic newborn screening programs will need to be rapidly and broadly implemented.

Asymptomatic HyperCKemia in the Pediatric Population: A Prospective Study Utilizing Next-Generation Sequencing and Ancillary Tests

BACKGROUND AND OBJECTIVES

Persistent elevation of serum creatine kinase levels (hyperCKemia) as an isolated manifestation presents a diagnostic challenge. Genetic myopathies are frequently involved; however, studies using next-generation sequencing (NGS) in pediatric patients are lacking, and the significance of genetic aberrations remains poorly understood. This study, therefore, aimed to investigate the relevance of NGS and the support of contemporary diagnostic tools in the diagnosis of pediatric asymptomatic hyperCKemia.

METHODS

This was a prospective cohort study enrolling pediatric (0-18 years old) patients meeting the predefined criteria for asymptomatic/paucisymptomatic hyperCKemia, excluding DMD gene deletion/duplication, recruited from a referral center. NGS, muscle MRI, EMG, and muscle biopsies with immunolabeling and inflammatory markers were performed according to a prespecified protocol. Data analysis was performed using descriptive/univariate statistics and Bayesian logistic regression.

RESULTS

The series comprised 65 patients (78% male). NGS diagnosis was achieved in 55% of the cohort, with 70% of the pathogenic variants involving 7 genes (DMD, CAPN3, ANO5, DYSF, RYR1, GAA, and CAV3). The diagnostic rate was similar across all age groups; however, the gene profiles varied between the childhood and juvenile groups. EMG yielded myopathic features in 48% of the investigated cases, being predictive for diagnosis (p < 0.05; odds ratio [OR] 13.484, 95% CI 1.358-705.297). MRI showed normal (64%), focal fatty change (26%), or short-tau inversion recovery hyperintensity (10%) profiles, which were not predictive of diagnosis but supported muscle biopsy indications. Muscle biopsy provided a significant diagnostic effect (p < 0.05; OR 0.028, 95% CI 0.001-0.238), contributing to myopathologic features clarifying the variant pathogenicity and identifying inflammatory myopathies. The diagnoses remained inconclusive and unresolved in 14% and 29% of the cohorts, respectively. The diagnostic rate for patients with CK levels below the threshold of 3× was 42%. In multivariate analysis, NGS was the only variable achieving a significant diagnostic effect (β = 9.85, 95% CI 4.65-16.09).

DISCUSSION

NGS, as the primary diagnostic tool for investigating hyperCKemia in the pediatric population, yielded a higher diagnostic rate. However, muscle biopsies are necessary to define variants of uncertain pathogenicity and aid in identifying inflammatory myopathies. EMG and MRI may play a role in hyperCKemia characterization, guiding the decision to perform muscle biopsy. The primary limitation of this study was that not all ancillary tests were performed in all recruited patients owing to ethical restrictions, which lowered the power of the predictive analysis.

Early diagnosis of Duchenne muscular dystrophy - A Treat-NMD international workshop

The diagnosis of Duchenne muscular dystrophy (DMD) is significant at any stage, however an early diagnosis in a presymptomatic or very early phase of DMD, offers unique opportunities and challenges for families and health care providers. Currently, there is limited evidence as to the optimal models of care during this stage of the condition.. To address this, in 2023, Treat-NMD facilitated the Early Diagnosis for DMD project; bringing together 42 experts from across Europe, the US and Australasia, including health care professionals, researchers, and people with lived experience to discuss the complexities of an early or newborn diagnosis of DMD, and provide recommendations regarding approaches to multidisciplinary care. A series of virtual meetings followed by a hybrid workshop resulted in broad recommendations to support clinicians in caring for children and families following an early diagnosis of DMD. The workshop did not define a cut-off for early diagnosis, however much of the discussion focused on diagnoses that occurred prior to 2 years. There is recognition that boys may first present with non-motor symptoms, such as speech delay or neurodevelopmental issues that are secondary to their dystrophinopathy, and therefore this report refers reflects that infants with DMD may be presymptomatic or early symptomatic.

A systematic framework for selecting gene-condition pairs for inclusion in newborn sequencing panels: Early Check implementation

PURPOSE

Research is underway worldwide to investigate the feasibility, acceptability, and utility of sequencing-based newborn screening. Different methods have been used to select gene-condition pairs for screening, leading to highly inconsistent gene lists across studies.

METHODS

Early Check developed and utilized actionability-based frameworks for evaluating gene-condition pairs for inclusion in newborn panels (panel 1-high actionability, panel 2-possible actionability). A previously developed framework, the Age-based Semi Quantitative Metric (ASQM), was adapted. Increasing ASQM scores, with a maximum of 15, suggest greater actionability. Wilcoxon tests were performed to compare panel 1 gene-condition pairs on the Recommended Uniform Screening Panel (RUSP) with non-RUSP pairs.

RESULTS

In our first round of assessment, Early Check identified 178 gene-condition pairs for inclusion in panel 1 and 29 for panel 2. Median ASQM scores of RUSP conditions on panel 1 was 12 (range 4 to 15) and non-RUSP was 13 (range 9 to 15). Median scores for panel 2 was 10 (range 6 to 14).

CONCLUSION

The Early Check frameworks provide a transparent, semiquantitative, and reproducible methodology for selecting gene-condition pairs for newborn screening sequencing pilot studies that may inform future integration of genomic sequencing into population-level newborn screening. Collaborative efforts among newborn sequencing studies to establish shared criteria is needed to enhance cross-study comparisons.

Diagnoses of muscular dystrophy in a veterans health system

INTRODUCTION/AIMS

Early diagnosis of a chronic neuromuscular disease such as muscular dystrophy (MD) generally excludes an individual from active-duty military service. However, it is not known whether veterans are sometimes diagnosed with milder forms of MD at a later timepoint. We aimed to determine the prevalence of MD in a veterans health system.

METHODS

We abstracted clinical and genetic test data on patients who received care for a diagnosis of MD at the North Florida/South Georgia Veterans Health System between 2008 and 2021. We then determined which of these individuals would meet criteria for a definite diagnosis of MD, based on electrodiagnostic testing, muscle biopsy, and genetic testing of the individual or an affected first degree relative.

RESULTS

We identified 12 patients with definite MD and 36 with possible or probable MD. The definite cases included myotonic dystrophy type 1 (4), myotonic dystrophy type 2 (3), oculopharyngeal MD (2), Becker MD (1), distal MD (1), and facioscapulohumeral MD (1). At least five of the cases classified as definite developed symptoms after discharge from active duty.

DISCUSSION

Clinicians who care for veterans should be knowledgeable about, and have access to, diagnostic testing and treatment options for MD. When conducting MD surveillance, it is important to include veterans health systems as a data source. Mild cases of MD and those of later onset appear to be compatible in some cases with successful completion of military service.

Age-Related Blood Levels of Creatine Kinase-MM in Newborns and Patients with Duchenne Muscular Dystrophy: Considerations for the Development of Newborn Screening Algorithms

Duchenne muscular dystrophy (DMD) is an X-linked progressive disorder and the most common type of muscular dystrophy in children. As newborn screening (NBS) for DMD undergoes evaluation for the Recommended Uniform Screening Panel and is already mandated in multiple states, refining NBS algorithms is of utmost importance. NBS for DMD involves measuring creatine kinase-MM (CK-MM) concentration-a biomarker of muscle damage-in dried blood spots. The current test is FDA-approved for samples obtained less than 72 h after birth. Separate reference ranges are needed for samples collected later than 72 h after birth. In this study, we investigated the relationship between age and CK-MM in presumed healthy newborns to inform NBS algorithm designs. In patients with DMD, CK-MM is persistently elevated in childhood and adolescence, while it may be transiently elevated for other reasons in healthy newborns. CK-MM decrease over time was demonstrated by a population sample of 20,306 presumed healthy newborns tested between 0 and 60 days of life and repeat testing of 53 newborns on two separate days. In the population sample, CK-MM concentration was highest in the second 12 h period of life (median = 318 ng/mL) when only 57.6% of newborns tested below 360 ng/mL, the lowest previously published cutoff. By 72 h of age, median CK-MM concentration was 97 ng/mL, and 96.0% of infants had concentrations below 360 ng/mL. Between 72 h and 60 days, median CK-MM concentration ranged from 32 to 37 ng/mL. Establishing age-related cutoffs is crucial for optimizing the sensitivity and specificity of NBS for DMD.

Current Status of Newborn Bloodspot Screening Worldwide 2024: A Comprehensive Review of Recent Activities (2020-2023)

Newborn bloodspot screening (NBS) began in the early 1960s based on the work of Dr. Robert "Bob" Guthrie in Buffalo, NY, USA. His development of a screening test for phenylketonuria on blood absorbed onto a special filter paper and transported to a remote testing laboratory began it all. Expansion of NBS to large numbers of asymptomatic congenital conditions flourishes in many settings while it has not yet been realized in others. The need for NBS as an efficient and effective public health prevention strategy that contributes to lowered morbidity and mortality wherever it is sustained is well known in the medical field but not necessarily by political policy makers. Acknowledging the value of national NBS reports published in 2007, the authors collaborated to create a worldwide NBS update in 2015. In a continuing attempt to review the progress of NBS globally, and to move towards a more harmonized and equitable screening system, we have updated our 2015 report with information available at the beginning of 2024. Reports on sub-Saharan Africa and the Caribbean, missing in 2015, have been included. Tables popular in the previous report have been updated with an eye towards harmonized comparisons. To emphasize areas needing attention globally, we have used regional tables containing similar listings of conditions screened, numbers of screening laboratories, and time at which specimen collection is recommended. Discussions are limited to bloodspot screening.

Assessing the Benefits and Harms Associated with Early Diagnosis from the Perspective of Parents with Multiple Children Diagnosed with Duchenne Muscular Dystrophy

Duchenne muscular dystrophy (DMD) is a rare neuromuscular disorder diagnosed in childhood. Limited newborn screening in the US often delays diagnosis. With multiple FDA-approved therapies, early diagnosis is crucial for timely treatment but may entail other benefits and harms. Using a community-based survey, we explored how parents of siblings with DMD perceived early diagnosis of one child due to a prior child's diagnosis. We assessed parents' viewpoints across domains including diagnostic journey, treatment initiatives, service access, preparedness, parenting, emotional impact, and caregiving experience. We analyzed closed-ended responses on a -1.0 to +1.0 scale to measure the degree of harm or benefit parents perceived and analyzed open-ended responses thematically. A total of 45 parents completed the survey, with an average age of 43.5 years and 20.0% identifying as non-white. Younger siblings were diagnosed 2 years earlier on average (p < 0.001). Overall, parents viewed early diagnosis positively (mean: 0.39), particularly regarding school preparedness (+0.79), support services (+0.78), treatment evaluation (+0.68), and avoiding diagnostic odyssey (+0.67). Increased worry was a common downside (-0.40). Open-ended responses highlighted improved outlook and health management alongside heightened emotional distress and treatment burdens. These findings address gaps in the evidence by documenting the effectiveness of early screening and diagnosis of DMD using sibling data.