Screening Panel Research Articles

Perceptions of severity and their influence on reproductive decision-making following reproductive genetic carrier screening.

The concept of severity in healthcare is multidimensional and subjective. It is a primary consideration in reproductive genetic carrier screening design where the focus is providing reproductive couples with information about the chance of severe genetic conditions in their offspring. When offering this screening, it is important to understand how condition severity is perceived and incorporated into reproductive decision-making. We analysed data from 41 semi-structured interviews with people who received a screening result indicating an increased chance for having children with a genetic condition. Thematic analysis revealed a desire for comprehensive information about the condition including clinical features, prognosis, impact on quality of life and treatment/management options. Participants integrated this information with their personal circumstances, beliefs/values and lived experience to form a perception of the severity of the condition. For rare and reduced-penetrance conditions where clinical information was limited or ambiguous, decision-making was more complex and greater anxiety was experienced. For conditions with a severity spectrum, reproductive decisions were based on the 'worst-case' clinical presentation. Where the impact of the condition was perceived as significant, the imperative to avoid that condition in future children appeared to be the greatest. Participants reported feeling that knowing their increased reproductive chance of the condition conferred a responsibility to avoid the condition, to prevent suffering and/or reduced quality of life for their children and future generations. These findings offer critical insight into how severity is perceived and the role it plays in reproductive decision-making and justifies a carefully considered approach to screening panel design.

Leveraging diverse genomic data to guide equitable carrier screening: Insights from gnomAD v.4.1.0.

Analysis of exome data from the latest release of the Genome Aggregation Database (gnomAD v.4.1.0) revealed a significant carrier burden of pathogenic/likely pathogenic (P/LP) variants in genes associated with autosomal-recessive conditions across diverse ancestral populations. Carrier screening panels are routinely offered to reproductive partners to inform their risk of having an affected child. Current guidelines from the American College of Medical Genetics and Genomics (ACMG) recommend screening for genes with a carrier frequency of at least 1/200 and associated with moderate/severe conditions. Here, we systematically analyzed >700,000 gnomAD v.4.1.0 exomes spanning eight ancestries to estimate the carrier frequency of P/LP variants in 2,987 genes associated with autosomal-recessive conditions. After expert curation for clinical severity, we identified 286 genes meeting the criteria for carrier screening. The number of genes exceeding the 1/200 threshold varied across populations, with 40 in the South Asian ancestry and up to 119 in the Ashkenazi Jewish population. Simulations showed that pan-ethnic screening panels offer advantages for individuals of diverse or admixed ancestry, while ancestry-specific panels may be preferable for genetically homogeneous populations. This study leveraged the most comprehensive genomic dataset to date to provide an updated candidate gene list for equitable carrier screening across diverse populations. Our findings highlight the need for continued expansion of genomic resources to better understand rare disease risk and inform screening efforts in underrepresented groups.

Long-Term Health Outcomes of Individuals With Pseudodeficiency Alleles in IDUA May Inform Newborn Screening Practices for Mucopolysaccharidosis Type I.

Mucopolysaccharidosis type I (MPS I), a lysosomal disorder caused by variants in IDUA, was added to the Recommended Uniform Screening Panel for newborn screening in 2016. Positive screening results for MPS I are commonly due to variants known as "pseudodeficiency alleles," which decrease invitro alpha-L-iduronidase enzyme activity but are thought to provide sufficient invivo activity. Despite the historic assumption that these variants are biologically benign, the possibility that they could give rise to complex, multigenic, or attenuated phenotypes has not been systemically evaluated in adults. We completed a retrospective matched cohort study using a hospital-based biorepository with data from 65,309 participants, we identified 1803 individuals harboring homozygous IDUA pseudodeficiency alleles. Using electronic medical records (EMR), we compared the prevalence of features of MPS I in participants with homozygous pseudodeficiency alleles to a cohort of matched control participants. We found no clinically relevant significant differences between cases and controls nor genotype-phenotype associations across four alleles. These findings provide empiric support that adults with homozygous IDUA pseudodeficiency alleles are unlikely to develop mild symptoms of disease compared with controls. This study provides a proof-of-concept model for other nonclassical disease variants related to other inherited metabolic disorders, which is necessary as newborn screening expands.

Bioluminescent Whole-Cell Bioreporter Bacterial Panel for Sustainable Screening and Discovery of Bioactive Compounds Derived from Mushrooms.

This study presents a rapid and comprehensive method for screening mushroom extracts for the putative discovery of bioactive molecules, including those exhibiting antimicrobial activity. This approach utilizes a panel of bioluminescent bacteria, whose light production is a sensitive indicator of various cellular effects triggered by the extracts, including disruption of bacterial communication (quorum sensing), protein and DNA damage, fatty acid metabolism alterations, and oxidative stress induction. The bioassay's strength is its ability to efficiently analyze a large number of extracts simultaneously while also assessing several different mechanisms of toxicity, significantly reducing screening time. All samples analyzed exhibited more than one cellular effect, as indicated by the reporter bacteria. Four samples (C. cornucopioides, F. fomentarius, I. obliquus, and M. giganteus) displayed the highest number (six) of possible mechanisms of antibacterial activity. Additionally, combining extraction and purification protocols with a bioluminescent bacterial panel enables simultaneous improvement of the desired antimicrobial properties of the extracts. The presented approach offers a valuable tool for uncovering the diverse antimicrobial mechanisms of mushroom extracts.

The Genomic Landscape of Wilson Disease in a Pan India Disease Cohort and Population-Scale Data.

Wilson's disease (WD) results from pathogenic ATP7B gene variations, causing copper accumulation mainly in the liver, brain, and kidneys. In India, despite studies on ATP7B variants, WD often goes undiagnosed, with the prevalence, carrier rate, and mutation spectrum remaining unknown. A multicenter study examined genetic variations in WD among individuals of Indian origin via whole exome sequencing. The study used the InDelible structural variants calling pipeline and conducted molecular dynamic simulations on variants of uncertain significance (VUS) in ATP7B AlphaFold protein structures. Additionally, a high-throughput gene screening panel for WD was developed. This study examined 128 clinically diagnosed cases of WD, revealing 74 genetically confirmed cases, 22 with ATP7B variants, and 32 without. Twenty-two novel ATP7B gene variants were identified, including a 322 bp deletion classified as a structural variant. Molecular dynamics simulations highlighted the potential deleterious effects of 11 ATP7B VUS. Gene burden analysis suggested associations with ANO8, LGR4, and CDC7. ATP7B gene hotspots for pathogenic variants were identified. Prevalence and carrier rates were determined as one in 18,678 and one in 67, respectively. A multiplex sequencing panel showed promise for accurate WD diagnosis. This study offers crucial insights into WD's genetic variations and prevalence in India, addressing its underdiagnosis. It highlights the novel genetic variants in the ATP7B gene, the involvement of other genes, a scalable, cost-effective multiplex sequencing panel for WD diagnosis and management and promising advancements in WD care.

Identification of a Novel Biomarker Panel for Breast Cancer Screening.

Breast cancer remains a major public health concern, and early detection is crucial for improving survival rates. Metabolomics offers the potential to develop non-invasive screening and diagnostic tools based on metabolic biomarkers. However, the inherent complexity of metabolomic datasets and the high dimensionality of biomarkers complicates the identification of diagnostically relevant features, with multiple studies demonstrating limited consensus on the specific metabolites involved. Unlike previous studies that rely on singular feature selection techniques such as Partial Least Square (PLS) or LASSO regression, this research combines supervised and unsupervised machine learning methods with random sampling strategies, offering a more robust and interpretable approach to feature selection. This study aimed to identify a parsimonious and robust set of biomarkers for breast cancer diagnosis using metabolomics data. Plasma samples from 185 breast cancer patients and 53 controls (from the Cooperative Human Tissue Network, USA) were analyzed. This study also overcomes the common issue of dataset imbalance by using propensity score matching (PSM), which ensures reliable comparisons between cancer and control groups. We employed Univariate Naïve Bayes, L2-regularized Support Vector Classifier (SVC), Principal Component Analysis (PCA), and feature engineering techniques to refine and select the most informative features. Our best-performing feature set comprised 11 biomarkers, including 9 metabolites (SM(OH) C22:2, SM C18:0, C0, C3OH, C14:2OH, C16:2OH, LysoPC a C18:1, PC aa C36:0 and Asparagine), a metabolite ratio (Kynurenine-to-Tryptophan), and 1 demographic variable (Age), achieving an area under the ROC curve (AUC) of 98%. These results demonstrate the potential for a robust, cost-effective, and non-invasive breast cancer screening and diagnostic tool, offering significant clinical value for early detection and personalized patient management.

Systematic screens for fertility genes essential for malaria parasite transmission reveal conserved aspects of sex in a divergent eukaryote

Sexual reproduction in malaria parasites is essential for their transmission to mosquitoes and offers a divergent eukaryote model to understand the evolution of sex. Through a panel of genetic screens in Plasmodium berghei, we identify 348 sex and transmission-related genes and define roles for unstudied genes as putative targets for transmission-blocking interventions. The functional data provide a deeper understanding of female metabolic reprogramming, meiosis, and the axoneme. We identify a complex of a SUN domain protein (SUN1) and a putative allantoicase (ALLC1) that is essential for male fertility by linking the microtubule organizing center to the nuclear envelope and enabling mitotic spindle formation during male gametogenesis. Both proteins have orthologs in mouse testis, and the data raise the possibility of an ancient role for atypical SUN domain proteins in coupling the nucleus and axoneme. Altogether, our data provide an unbiased picture of the molecular processes that underpin malaria parasite transmission. A record of this paper's transparent peer review process is included in the supplemental information.

Investigation of Wright Blood Group Alleles and Genotypes in Malaria-Endemic Area in Southwestern Saudi Arabia.

Inherited blood disorders as well as malaria are prevalent in southwestern Saudi Arabia. Patients with specific hemoglobinopathies may require frequent blood transfusions. Accordingly, alloimmunization may occur if donors and recipients are incompatible. Therefore, examination of various blood group antigens to provide compatible blood units is essential. Two alleles of the Diego (DI) blood group system, DI*02.03 and DI*02.04 encode the Wright antigens; Wra and Wrb, respectively. Anti-Wra may lead to alloimmunization during transfusion and pregnancy. Furthermore, the Wrb antigen may involve in interaction between protein receptors for Plasmodium falciparum. This study aimed to investigate the allele/genotype frequencies of the Wright blood groups in southwestern Saudi blood donors regarding the blood transfusion and assessed the population of Jazan Province for susceptibility of Plasmodium falciparum invasion. One-hundred-fifty Saudi blood donors were enrolled to this study. DNA was extracted from the blood samples. Primer pairs were designed to capture a single nucleotide variation that distinguishes the Wright alleles. Polymerase chain reaction (PCR) was conducted and followed by standard sequencing. Among the 150 genotyped samples, the only observed allele was DI*02.04 (n = 150, 100%). Accordingly, the genotype prevalence of DI*02.04/DI*02.04 was accounted for (n = 150, 100%). This study demonstrated the allele frequencies of DI*02.03 and DI*02.04 of the DI blood group system in Saudi blood donors. The DI*02.04 allele was the only allele that was observed. Furthermore, the prevalence of the genotypes was determined and the only observed genotype was DI*02.04/DI*02.04. Interestingly, this study indicates that the Saudi Arabian population living in Jazan Province may be more susceptible to Plasmodium falciparum invasion. Moreover, adding the Wright alleles for the transfusion screening panel is not recommended.

Expanded carrier screening for 216 diseases in a cohort of 3 097 healthy Chinese individuals of childbearing age

Objective: To determine the carrier frequency and hot-spot variants of a custom-designed expanded carrier screening (ECS) panel with 216 diseases (216-ECS panel) within a Chinese population of childbearing age. Methods: Whole-exome sequencing data from a cohort of 3 097 unrelated healthy individuals (including 1 424 couples) from Peking Union Medical College Hospital between January 2013 and December 2023 were analyzed. Totally 220 genes which inherited in a recessive manner of 216-ECS panel were included in the analysis. The analysis included variant carrier rate, gene carrier rate, cumulative carrier rate, at-risk couple rates, and variant spectrum. Results: (1) Pathogenic variants were identified in 1 472 (47.53%, 1 472/3 097) individuals, with an average of 0.65 pathogenic variants per individual. The rate of at-risk couples was 3.93% (56/1 424). (2) A total of 180 genes were identified, with 16 genes exhibiting a gene carrier rate of ≥1% and 33 genes having a rate of ≥0.5%, most of which were associated with inherited metabolic diseases. Noteworthy genes with higher gene carrier rates and high-frequency variants included GJB2: c.235del, PAH: c.728G>A, ATP7B: c.2333G>T, SLC26A4: c.919-2A>G, GALC: c.1901T>C, POLG: c.2890C>T, SLC22A5: c.1472C>G, USH2A: c.2802T>G, SLC25A13: c.852_855del, GAA: c.761C>T and c.752C>T. Conclusion: This study offers a focused analysis of carrier frequencies and hot-spot variants of 216 diseases of the ECS panel constructed by our laboratory among the Chinese population, laying a foundation for the development of ECS programs tailored to the Chinese population.

An exploratory study of perceptions and utilization of genetic information in the intended parent experience of oocyte donor selection.

Utilization of oocyte donation has become an increasingly common practice in assisted reproductive technology (ART). Since the introduction of larger carrier screening (CS) panels and extended family medical histories (EFMH), studies have not examined how this information factors into the oocyte donor selection process. This exploratory, qualitative study provides further insight into what role, if any, donors' available genetic information (e.g., larger CS panels and EFMH) plays in selecting an oocyte donor. An online screening survey was distributed to individuals who have undergone or are currently in the process of selecting an oocyte donor through the RESOLVE network and Mayo Clinic's Reproductive Endocrinology and Infertility clinic. From 13 survey respondents, six oocyte recipients subsequently participated in semi-structured telephone interviews and discussed their experiences as oocyte recipients including their perceptions of donors' available genetic information and process in choosing an oocyte donor. Genetic information was seen as valuable and reassuring for participants, particularly EFMH, but did not play a significant role in the selection process for these participants. Supplemental emergent themes provide context on the psychosocial complexities of the oocyte recipient experience and possible explanations for why genetic information is not a decisional priority. Participants indicated genetic information was not extensively discussed or fully explained by providers. Results demonstrate how genetic counselors can be more involved in the pre-selection process to discuss the utility and limitations of genetic information, as well as address psychosocial issues common to the oocyte recipient experience.

A novel machine-learning aided platform for rapid detection of urine ESBLs and carbapenemases: URECA-LAMP.

Pathogenic gram-negative bacteria frequently carry genes encoding extended-spectrum beta-lactamases (ESBL) and/or carbapenemases. Of great concern are carbapenem resistant Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa, and Acinetobacter baumannii. Despite the need for rapid AMR diagnostics globally, current molecular detection methods often require expensive equipment and trained personnel. Here, we present a novel machine-learning-aided platform for the rapid detection of ESBLs and carbapenemases using Loop-mediated isothermal Amplification (LAMP). The platform consists of (i) an affordable device for sample lysis, LAMP amplification, and visual fluorometric detection; (ii) a LAMP screening panel to detect the most common ESBL and carbapenemase genes; and (iii) a smartphone application for automated interpretation of results. Validation studies on clinical isolates and urine samples demonstrated percent positive and negative agreements above 95% for all targets. Accuracy, precision, and recall values of the machine learning model deployed in the smartphone application were all above 92%. Providing a simplified workflow, minimal operation training, and results in less than an hour, this study demonstrated the platform's feasibility for near-patient testing in resource-limited settings.IMPORTANCEExtended-spectrum beta-lactamases (ESBL) and carbapenemases confer resistance to third-generation cephalosporins and carbapenems in pathogenic Gram-negative bacteria such as Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa, and Acinetobacter baumannii. Conventional antimicrobial susceptibility testing is based on phenotypic methods, and results can take several days to be obtained. Current genotypic detection methods can be rapid but require expensive equipment and trained personnel. In this study, we present a novel machine learning-aided platform for the rapid detection of ESBLs and carbapenemases using Loop-mediated isothermal Amplification (LAMP). The validation of the platform demonstrated percent positive and negative agreements above 95% for all targets. The newly developed platform provided a simplified workflow, minimal technical training, and results in less than an hour. This study demonstrated the platform's feasibility for rapid testing of ESBL and carbapenemases in bacteria and urine specimens.

Evaluation of Anti-k Antibody in a Patient Undergoing Redo Sternotomy

Abstract Introduction/Objective Introduction: The Kell blood group system, discovered in 1946, holds paramount significance in transfusion medicine and hemolytic disease of the newborn (HDN). Named after Mrs. Kelleher, who exhibited anti-Kell antibodies resulting in HDN, this system comprises 25 antigens, with the original K antigen retaining primary importance. Additionally, Levine et al. identified anti-Cellano, now known as anti-k, presenting an antibody antithetical to anti-K. Methods/Case Report Case Presentation: A 60-year-old male with a history of bioprosthetic aortic valve insufficiency, pulmonary homograft stenosis, and recurrent aortic insufficiency presents for a fourth redo sternotomy for root and ascending aorta replacement. Preoperative assessment revealed a positive antibody screen for anti-k, a clinically significant antibody associated with decreased survival of transfused red blood cells (RBCs). Given limited compatible blood units available, efforts are underway to secure additional donations before the scheduled surgery on 2/22/24. The patient’s medical history indicates no recent blood transfusions or iron therapy, with the last transfusion in 1996. He is anticoagulated with warfarin for mechanical valve and atrial fibrillation, necessitating preoperative bridging with Lovenox injections. Methods The patient’s antibody screen and initial panel demonstrated pan-reactivity with 3+ reactivity, suggesting an antibody targeting a high-frequency antigen. Further testing using polyethylene glycol (PEG) confirmed the presence of anti-k, supported by negative reactions to additional K-negative cells. The absence of other clinically significant antibodies was verified using 0.2 M Dithiothreitol (DTT) modified cells. Results (if a Case Study enter NA) NA Conclusion Conclusion: The identification of anti-k antibody underscores the critical role of preoperative antibody screening in mitigating transfusion-related complications, particularly in patients requiring complex surgical interventions. Collaborative efforts between clinical teams and transfusion medicine specialists are imperative to ensure adequate blood product availability and optimize patient outcomes.To prevent further exposure, it is recommended that patients with rare antibodies carry an Antibody ID card indicating the rare antibody they possess.k antigen blood donors are underrepresented in the general donor pool. It is recommended to develop a systematic recruitment for k antigen donors.

A Systematic Literature Review on the Global Status of Newborn Screening for Mucopolysaccharidosis II.

A systematic literature review was conducted to determine the global status of newborn screening (NBS) for mucopolysaccharidosis (MPS) II (Hunter syndrome; OMIM 309900). Electronic databases were searched in July 2023 for articles referencing NBS for lysosomal storage diseases: 53 featured MPS II. Until recently, only Taiwan and two US states (Illinois and Missouri) formally screened newborns for MPS II, although pilot programs have been conducted elsewhere (Japan, New York, and Washington). In 2022, MPS II was added to the US Recommended Uniform Screening Panel, with increased uptake of NBS anticipated across the USA. While the overall MPS II birth prevalence, determined from NBS initiatives, was higher than in previous reports, it was lower in the USA (approximately 1 in 73,000 according to recent studies in Illinois and Missouri) than in Asia (approximately 1 in 15,000 in Japan). NBS programs typically rely on tandem mass spectrometry quantification of iduronate-2-sulfatase activity for first-tier testing. Diagnosis is often confirmed via molecular genetic testing and/or biochemical testing but may be complicated by factors such as pseudodeficiency alleles and variants of unknown significance. Evidence relating to MPS II NBS is lacking outside Taiwan and the USA. Although broad benefits of NBS are recognized, few studies specifically explored the perspectives of families of children with MPS II.

Risk of Hepatitis B Virus Reactivation in COVID-19 Patients Receiving Immunosuppressive Treatment: A Prospective Study.

Objectives: This study aimed to evaluate the risk of hepatitis B virus reactivation (HBVr) in COVID-19 patients receiving immunosuppressive treatment, which has been insufficiently studied to date. Secondarily, we aimed to evaluate the seroprevalence of HBV infection in COVID-19 patients. Methods: We performed HBV screening on all Romanian adults hospitalized in four COVID-19 wards between October 2021 and September 2022. We enrolled patients with positive hepatitis B core antibody (anti-HBc) without protective hepatitis B surface antibody (anti-HBs), HBV treatment, or baseline immunosuppressive conditions, and we conducted a virological follow-up on these patients at 3 months. Results: We identified 333/835 (39.9%) anti-HBc-positive patients. Follow-up was performed for 13 patients with positive hepatitis B surface antigen (HBsAg) and 19 HBsAg-negative/anti-HBc-positive patients. Among those who received immunosuppressants, 4/23 (17.4%) patients experienced HBVr: 1 out of 8 (12.5%) HBsAg-positive patients (with 1.99 log increase in HBV DNA level) and 3 out of 15 (20%) HBsAg-negative/anti-HBc-positive patients (with a de novo detectable HBV DNA level). Conclusions: Administration of COVID-19 immunosuppressants may result in a significant risk of HBVr in co-infected patients. We recommend performing an HBV triple screen panel (HBsAg, anti-HBs, anti-HBc) for all COVID-19 patients receiving immunosuppressive treatment. HBV prophylaxis may be indicated in certain patients. Larger studies are needed in order to establish appropriate and cost-effective management for these patients.

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

PurposeResearch 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. MethodsEarly 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. ResultsIn 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). ConclusionThe 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.

Anti-SARS-CoV-2 IgM Antibody Levels Measured by an In-House ELISA in a Convalescent Latin Population Persist over Time and Exhibit Neutralizing Capacity to Several Variants of Concern.

The coronavirus, SARS-CoV-2, is the causative agent for COVID-19, first registered in Wuhan, China and responsible for more than 6 million deaths worldwide. Currently, RT-PCR is the gold-standard method for diagnosing COVID-19. However, serological tests are needed for screening acute disease diagnosis and screening large populations during the COVID-19 outbreak. Herein, we described the development and validation of an in-house enzyme-linked immunosorbent assay (ELISA) for detecting the levels of anti-spike-1-RBD IgM antibody (CovIgM-ELISA) in well-defined serum/plasma panel for screening and identifying subjects infected with SARS-CoV-2 in a Latin population. In-house CovIgM-ELISA has the format of an indirect ELISA. It was optimized by checkerboard titration using recombinant SARS-CoV-2 spike-S1-RBD protein as an antigen. We found that, compared to the RT-PCR as the standard method, the in-house CovIgM-ELISA displayed sensitivities of 96.15% and 93.22% for samples collected up to 30 or 60 days after infection, respectively, as well as 95.59% specificity with 97.3% accuracy. The agreement kappa value (κ) of our CovIgM-ELISA was substantial when compared to RT-PCR (κ = 0.873) and the anti-SARS-CoV-2 IgM ELISA (InBios Int) (κ = 0.684). The IgM levels detected in the population positively correlated with the neutralizing activity against the wild-type, Alpha and Delta variants of concern, but failed to neutralize Omicron. These data indicate that our in-house CovIgM-ELISA is a compatible performing assay for the detection of SARS-CoV-2 infection.

A-320 Determination of Guanidinoacetate Methyltransferase Enzyme Biomarkers in Newborn Dried Blood Spot by Tandem Mass Spectrometry-A Two Tier Approach

Abstract Background Guanidinoacetate methyltransferase enzyme (GAMT) deficiency is a rare, inherited metabolic disorder that affects the synthesis of creatine. Creatine is an essential metabolite for regenerating energy, particularly in the brain and muscles. Creatine is synthesized from guanidinoacetate (GUAC) by the GAMT enzyme. Mutations in the GAMT gene result in a shortage of the GAMT enzyme that causes a deficiency of creatine and accumulation of GUAC in the body, which is a neurotoxin. Following a recommendation by the Recommended Uniform Screening Panel and in line with California State statute, all California newborns will be screened for GAMT deficiency beginning July 2024. Here, we developed and validated a quantitative two-tier tandem mass spectrometry (MS/MS) assay for the detection of GAMT biomarkers (GUAC, creatine and creatinine) in newborn dried blood spot (DBS). Methods This method punches a 3.2 mm disc of controls and newborn patient DBS into a 96-well plate. 100 μL of extraction solution, containing internal standards of GAMT biomarkers, is added to each well and incubated at 40°C for 45 minutes. The extract is transferred, evaporated, and derivatized into a 3N-butanol-HCl solution at 60°C for 30 minutes. The excess HCl is evaporated to dryness. The conversion of GUAC and creatine to their butyl esters has improved their detection sensitivity by MS/MS. The butyl esters are reconstituted into the mobile phase and shaken for 10 minutes at 27°C. The final 10 μL extract was analyzed by flow injection analysis (FIA)-MS/MS in multiple reaction monitoring (MRM) positive ion mode with a total run time of 1.5 minutes per sample. The presumptive positive samples from initial analysis are prepared following the same method, and a 5 μL extract is resolved through an ultra-performance liquid chromatography (UPLC) column and analyzed by UPLC-MS/MS in MRM positive ion mode with a total run time of 3.5 minutes per sample. The validation was performed by assessing the linearity, accuracy, imprecision, carryover, limit of detection (LOD) and lower limit of quantitation (LLOQ), matrix effect, analytical measurement range (AMR), percent total allowable error (TEa), and reference range. Results This method is linear for GUAC, creatine and creatinine over a measured range of 1.17-40.00, 121.20-857.36 and 41.34-387.46 µmol/L respectively. The R2 values=1.000, 0.997, 0.9998; slope=0.999, 0.9945, 0.9982; intercept=0.0398, 4.881, 1.7027; mean recoveries=99-104%, 100-104%, 100-104%; intra-assay precision (n=20) =4.05-5.95%, 4.62-5.31%, 3.27-5.19%, inter-assay precision (n=40)=3.7-12.6%, 4.3-7.6%, 3.8-7.4%; TEa=6-21%, 7-17%, 6-17%; LOD=0.12, 0.54, 1.11 µmol/L; AMR=0.33-1300, 1.11-2700, 3.50-4500 µmol/L; median patient results observed from 2293 normal patient=1.48, 494.02, 89.97 μmol/L for GUAC, creatine, and creatinine respectively. The tier-1 and tier-2 assay screening cutoff for GUAC at the population 95th percentile is 2.53 and 4.55 μmol/L respectively. Conclusions The tier-1 and tier-2 methods has been developed and validated to determine GAMT biomarkers in newborn DBS, making it suitable for routine screening of ∼2000 newborn specimens per day by tier-1 and followed by more specific tier-2 to separate GAMT biomarkers from potential isobaric interfering compounds. This two-tier approach greatly improved the test performance and significantly reduced false positive rate.

Practical Approach to Longitudinal Neurologic Care of Adults With X-Linked Adrenoleukodystrophy and Adrenomyeloneuropathy.

Although X-linked adrenoleukodystrophy (ALD) has historically been considered a childhood disease managed by pediatric neurologists, it is one of the most common leukodystrophies diagnosed in adulthood. An increase in both male and female adults reaching diagnosis due to familial cases identified by state newborn screening panels and more widespread use of genetic testing results in a large cohort of presymptomatic or early symptomatic adults. This population is in urgent need of standardized assessments and follow-up care. Adults with ALD/adrenomyeloneuropathy (AMN) may be diagnosed in a variety of ways, including after another family member is identified via genetic testing or newborn screening, presenting for symptomatic evaluation, or following diagnosis with primary adrenal insufficiency. Significant provider, patient, and systems-based barriers prevent adult patients with ALD/AMN from receiving appropriate care, including lack of awareness of the importance of longitudinal neurologic management. Confirmation of and education about the diagnosis should be coordinated in conjunction with a genetic counselor. Routine surveillance for adrenal insufficiency and onset of cerebral ALD (CALD) in men should be performed systematically to avoid preventable morbidity and mortality. While women with ALD do not usually develop cerebral demyelination or adrenal insufficiency, they remain at risk for myeloneuropathy and are no longer considered "carriers." After diagnosis, patients should be connected to the robust support networks, foundations, and research organizations available for ALD/AMN. Core principles of neurologic symptom management parallel those for patients with other etiologies of progressive spastic paraplegia. Appropriate patient candidates for hematopoietic stem cell transplant (HSCT) and other investigational disease-modifying strategies require early identification to achieve optimal outcomes. All patients with ALD/AMN, regardless of sex, age, or symptom severity, benefit from a multidisciplinary approach to longitudinal care spearheaded by the neurologist. This review proposes key strategies for diagnostic confirmation, laboratory and imaging surveillance, approach to symptom management, and guidance for identification of appropriate candidates for HSCT and investigational treatments.

Estimating the sensitivity of genomic newborn screening for treatable inherited metabolic disorders

PurposeOver 30 research groups and companies are exploring newborn screening using genomic sequencing (NBSeq), but the sensitivity of this approach is not well understood. MethodsWe identified individuals with treatable inherited metabolic disorders (IMDs) and ascertained the proportion whose DNA analysis revealed explanatory deleterious variants (EDVs). We examined variables associated with EDV detection and estimated the sensitivity of DNA-first NBSeq. We further predicted the annual rate of true-positive and false-negative NBSeq results in the United States for several conditions on the Recommended Uniform Screening Panel. ResultsWe identified 635 individuals with 80 unique IMDs. In univariate analyses, Black race (OR = 0.37, 95% CI: 0.16-0.89, P = .02) and public insurance (OR = 0.60, 95% CI: 0.39-0.91, P = .02) were less likely to be associated with finding EDVs. Had all individuals been screened with NBSeq, the sensitivity would have been 80.3%. We estimated that between 0 and 649.9 cases of Recommended Uniform Screening Panel IMDs would be missed annually by NBSeq in the United States. ConclusionThe overall sensitivity of NBSeq for treatable IMDs is estimated at 80.3%. That sensitivity will likely be lower for Black infants and those who are on public insurance.

Identification of potent and orally efficacious phosphodiesterase inhibitors in Cryptosporidium parvum-infected immunocompromised male mice

Cryptosporidium parvum and C. hominis are parasites that cause life-threatening diarrhea in children and immunocompromised people. There is only one approved treatment that is modestly effective for children and ineffective for AIDS patients. Here, screening 278 compounds from the Merck KGaA, Darmstadt, Germany collection and accelerated follow-up enabled by prior investigation of the compounds identifies a series of pyrazolopyrimidine human phosphodiesterase (PDE)-V (hPDE-V) inhibitors with potent anticryptosporidial activity and efficacy following oral administration in C. parvum-infected male mice. The lead compounds affect parasite host cell egress, inhibit both C. parvum and C. hominis, work rapidly, and have minimal off-target effects in a safety screening panel. Interestingly, the hPDE-V inhibitors sildenafil and the 4-aminoquinoline compound 7a do not affect Cryptosporidium. C. parvum expresses one PDE (CpPDE1) continuously during asexual growth, the inhibited life stage. According to homology modeling and docking, the lead compounds interact with CpPDE1. Bulkier amino acids (Val900 and His884) in the CpPDE1 active site replace alanines in hPDE-V and block sildenafil binding. Supporting this, sildenafil kills a CRISPR-engineered Cryptosporidium CpPDE1 V900A mutant. The CpPDE1 mutation also alters parasite susceptibility to pyrazolopyrimidines. CpPDE1 is therefore a validated pyrazolopyrimidine molecular target to exploit for target-based optimization for improved anticryptosporidial development.