Newborn Dried Blood Spots Research Articles

Generation Scotland participant survey on data collection

Background: Generation Scotland (GS) is a population and family-based study of genetic and environmental health determinants. Recruitment to the Scottish Family Health Study component of GS took place between 2006-2011. Participants were aged 18 or over and consented to genetic studies, linkage to health records and recontact. Several recontact exercises have been successfully conducted aimed at a) recruitment to embedded or partner studies and b) the collection of additional data. As the cohort matures in age, we were interested in surveying attitudes to potential new approaches to data collection and recruitment. Methods: A ten-question online survey was sent to those participants who provided an email address. Results: We report a high level of positive responses to encouraging relatives to participate, to remote data and sample collection and for research access to stored newborn dried blood spots. Conclusions: The majority of current and prospective GS participants are likely to respond positively to future requests for remote data and sample collection.

Fluorimetric assay with a novel substrate for quantification of galactocerebrosidase activity in dried blood spot specimens

BackgroundDecreased galactocerebrosidase (GALC) enzyme activity is causative for Krabbe disease, a lysosomal storage disorder with devastating neurodegenerative consequences. Quantitative fluorimetric assays for GALC activity in isolated blood and skin cells have been described; however, no such assay has been described using dried blood spot (DBS) specimens. MethodsGALC enzyme activity was measured quantitatively using fluorescence from a novel glycosidic substrate: carboxy derived from 6-hexadecanoylamino-4-methylumbelliferone. GALC activity was demonstrated on newborn DBS specimens, known Krabbe disease patient specimens, proficiency testing and quality control samples. ResultsWe present data on characterization of the novel substrate and assay, including pH optimization and enzyme kinetics using a fluorimetric profile. Single and multi-day precision analyses revealed tight analytical measurements with %CV ranging from 5.2% to 14.1%. GALC enzyme activity was linear over the range of 0.31 - 12.04 μmol/l/h with a limit of detection of 0.066 μmol/l/h. Our results with this assay show a clear discrimination between GALC activities in samples from Krabbe disease patients versus presumed normal newborn samples. ConclusionsA fluorimetric assay for GALC enzyme activity measurement on dried blood spot specimens is feasible. Improvements to the assay including novel substrate design, increased substrate concentration and removal of sodium chloride maximize the specificity of the assay and minimize interference from β-galactosidase.

Generation Scotland participant survey on data collection

Background: Generation Scotland (GS) is a population and family-based study of genetic and environmental health determinants. Recruitment to the Scottish Family Health Study component of GS took place between 2006-2011. Participants were aged 18 or over and consented to genetic studies, linkage to health records and recontact. Several recontact exercises have been successfully conducted aimed at a) recruitment to embedded or partner studies and b) the collection of additional data. As the cohort matures in age, we were interested in surveying attitudes to potential new approaches to data collection and recruitment. Methods: A ten-question online survey was sent to those participants who provided an email address. Results: We report a high level of positive responses to encouraging relatives to participate, to remote data and sample collection and for research access to stored newborn dried blood spots. Conclusions: The majority of current and prospective GS participants are likely to respond positively to future requests for remote data and sample collection.

Combining newborn metabolic and DNA analysis for second-tier testing of methylmalonic acidemia

PurposeImproved second-tier tools are needed to reduce false-positive outcomes in newborn screening (NBS) for inborn metabolic disorders on the Recommended Universal Screening Panel (RUSP).MethodsWe designed an assay for multiplex sequencing of 72 metabolic genes (RUSPseq) from newborn dried blood spots. Analytical and clinical performance was evaluated in 60 screen-positive newborns for methylmalonic acidemia (MMA) reported by the California Department of Public Health NBS program. Additionally, we trained a Random Forest machine learning classifier on NBS data to improve prediction of true and false-positive MMA cases.ResultsOf 28 MMA patients sequenced, we found two pathogenic or likely pathogenic (P/LP) variants in a MMA-related gene in 24 patients, and one pathogenic variant and a variant of unknown significance (VUS) in 1 patient. No such variant combinations were detected in MMA false positives and healthy controls. Random Forest–based analysis of the entire NBS metabolic profile correctly identified the MMA patients and reduced MMA false-positive cases by 51%. MMA screen-positive newborns were more likely of Hispanic ethnicity.ConclusionOur two-pronged approach reduced false positives by half and provided a reportable molecular finding for 89% of MMA patients. Challenges remain in newborn metabolic screening and DNA variant interpretation in diverse multiethnic populations.

Newborn vitamin D levels in relation to autism spectrum disorders and intellectual disability: A case-control study in california.

Vitamin D deficiency has been increasing concurrently with prevalence of autism spectrum disorders (ASD), and emerging evidence suggests vitamin D is involved in brain development. Most prior studies of ASD examined vitamin D levels in children already diagnosed, but a few examined levels during perinatal development, the more likely susceptibility period. Therefore, we examined newborn vitamin D levels in a case-control study conducted among births in 2000-2003 in southern California. Children with ASD (N = 563) or intellectual disability (ID) (N = 190) were identified from the Department of Developmental Services and compared to population controls (N = 436) identified from birth certificates. 25-hydroxyvitamin D (25(OH)D) was measured in archived newborn dried blood spots by a sensitive assay and corrected to sera equivalents. We categorized 25(OH) D levels as deficient (<50 nmol/L), insufficient (50-74 nmol/L), and sufficient (≥75 nmol/L), and also examined continuous levels, using logistic regression. The adjusted odds ratios (AOR) and 95% confidence intervals for ASD were 0.96 (0.64-1.4) for 25(OH)D deficiency (14% of newborns) and 1.2 (0.86-1.6) for insufficiency (26% of newborns). The AORs for continuous 25(OH)D (per 25 nmol/L) were 1.0 (0.91-1.09) for ASD and 1.14 (1.0-1.30) for ID. Thus, in this relatively large study of measured newborn vitamin D levels, our results do not support the hypothesis of lower 25(OH)D being associated with higher risk of ASD (or ID), although we observed suggestion of interactions with sex and race/ethnicity. 25(OH)D levels were relatively high (median 84 nmol/L in controls), so results may differ in populations with higher prevalence of low vitamin D levels. Autism Res 2019, 12: 989-998. © 2019 International Society for Autism Research, Wiley Periodicals, Inc. LAY SUMMARY: We studied whether vitamin D levels measured at birth were related to whether a child later developed autism (or low IQ). Our results did not show that children with autism, or low IQ, overall had lower vitamin D levels at birth than children without autism. Vitamin D levels were fairly high, on average, in these children born in Southern California.

Untargeted adductomics of Cys34 modifications to human serum albumin in newborn dried blood spots.

Metabolism of chemicals from the diet, exposures to xenobiotics, the microbiome, and lifestyle factors (e.g., smoking, alcohol intake) produce electrophiles that react with nucleophilic sites in circulating proteins, notably Cys34 of human serum albumin (HSA). To discover potential risk factors resulting from in utero exposures, we are investigating HSA-Cys34 adducts in archived newborn dried blood spots (DBS) that reflect systemic exposures during the last month of gestation. The workflow includes extraction of proteins from DBS, measurement of hemoglobin (Hb) to normalize for blood volume, addition of methanol to enrich HSA by precipitation of Hb and other interfering proteins, digestion with trypsin, and detection of HSA-Cys34 adducts via nanoflow liquid chromatography-high-resolution mass spectrometry. As proof-of-principle, we applied the method to 49 archived DBS collected from newborns whose mothers either actively smoked during pregnancy or were nonsmokers. Twenty-six HSA-Cys34 adducts were detected, including Cys34 oxidation products, mixed disulfides with low molecular weight thiols (e.g., cysteine, homocysteine, glutathione, cysteinylglycine), and other modifications. Data were normalized with a novel method ("scone") to remove unwanted technical variation arising from HSA digestion, blood volume, DBS age, mass spectrometry analysis, and batch effects. Using an ensemble of linear and nonlinear models, the Cys34 adduct of cyanide was found to consistently discriminate between newborns of smoking and nonsmoking mothers with a mean fold change (smoking/nonsmoking) of 1.31. These results indicate that DBS adductomics is suitable for investigating in utero exposures to reactive chemicals and metabolites that may influence disease risks later in life.

Analysis of Inflammatory Mediators in Newborn Dried Blood Spot Samples by Chip-Based Immunoaffinity Capillary Electrophoresis.

A chip-based immunoaffinity capillary electrophoresis (ICE) system has been developed for measuring inflammatory mediators in dried blood samples routinely taken from newborn babies. A defined area of each dried blood spot was removed from the sample card and its contents eluted. The recovered eluates were injected into the chip and the analytes of interest isolated by the immunoaffinity disk within the chip. The captured analytes were labeled in-situ with a red light-emitting laser dye and electro-eluted into the chip separation channel. Electrophoretic separation of all of the analytes was achieved within 2.0min with quantification of each peak being performed by online LIF detection and integration of each peak area. The degree of accuracy and precision achieved by the chip-based system is comparable to conventional immunoassays and the system is robust enough to be applied to the analysis of clinical samples.

Examining Endocrine Disruptors Measured in Newborn Dried Blood Spots and Early Childhood Growth in a Prospective Cohort.

The goal of this study was to determine whether newborn concentrations of perfluorooctane sulfonic acid (PFOS), perfluorooctanoic acid (PFOA), and bisphenol A (BPA) are associated with early childhood growth. A total of 1,954 singletons and 966 twins from the Upstate KIDS Study (born 2008-2010) were included in this study. Newborn dried blood spot concentrations of PFOS, PFOA, and BPA were quantified by liquid chromatography tandem mass spectrometry. Children's weight and height were reported from birth through 3 years of age. Repeated measures were modeled using generalized linear mixed models. PFOS and PFOA were associated with lower BMI (-0.078 kg/m2 [-0.12 to -0.038] and -0.076 kg/m2 [-0.17 to -0.051] per 1 standard deviation increase in log PFOS and PFOA, respectively) and not with early obesity among singletons. Inconsistent associations were observed for twins. BPA levels were higher among neonates with a neonatal intensive care unit stay (P < 0.001), making associations difficult to interpret. Perfluorinated alkyl substances did not exhibit obesogenic associations with early measures of childhood growth. Blood-based BPA measures are limited by the nonpersistent nature of the chemical, and unknown sources from hospital settings may present only transient exposures.

Newborn screening for cerebrotendinous xanthomatosis is the solution for early identification and treatment

Cerebrotendinous xanthomatosis (CTX) is a progressive metabolic leukodystrophy. Early identification and treatment from birth onward effectively provides a functional cure, but diagnosis is often delayed. We conducted a pilot study using a two-tier test for CTX to screen archived newborn dried bloodspots (DBSs) or samples collected prospectively from a high-risk Israeli newborn population. All DBS samples were analyzed with flow injection analysis (FIA)-MS/MS, and 5% of samples were analyzed with LC-MS/MS. Consecutively collected samples were analyzed to identify CTX-causing founder genetic variants common among Druze and Moroccan Jewish populations. First-tier analysis with FIA-MS/MS provided 100% sensitivity to detect CTX-positive newborn DBSs, with a low false-positive rate (0.1-0.5%). LC-MS/MS, as a second-tier test, provided 100% sensitivity to detect CTX-positive newborn DBSs with a false-positive rate of 0% (100% specificity). In addition, 5β-cholestane-3α,7α,12α,25-tetrol-3-O-β-D-glucuronide was identified as the predominant bile-alcohol disease marker present in CTX-positive newborn DBSs. In newborns identifying as Druze, a 1:30 carriership frequency was determined for the c.355delC CYP27A1 gene variant, providing an estimated disease prevalence of 1:3,600 in this population. These data support the feasibility of two-tier DBS screening for CTX in newborns and set the stage for large-scale prospective pilot studies.

Newborn dried blood spot samples in Denmark: the hidden figures of secondary use and research participation

Each year millions of newborns are part of a newborn disease-screening program in which, after initial screening, the newborn dried blood spot (NDBS) samples can be stored and used as a population-based research resource. However, very little knowledge exists about how these samples are used for secondary purposes. Our objective is to estimate and describe the usage of a NDBS-based national population biobank for secondary research purposes. We therefore conducted a scoping study with a literature search for all published articles using samples from the Danish Newborn Screening Biobank. Our main inclusion criteria were that the articles had to have actively used and analyzed one or more of the Danish NDBS samples for a purpose beyond the primary screening. Our search led to a final 104 articles, which were coded for three main purposes: (1) how many samples were used in each article, (2) the field of their research, and (3) information on consent and ethics approval as research. From our analysis, we present two main findings: an estimated use of up to 37.5% of all samples in the newborn screening biobank have been part of published research, and a shift in the research areas from methodological and metabolic studies to studies concerning mental illness. This paper provides new insights into the use of a national biobank, and we hope that the results will contribute to the discussions on the use of biological samples for research purposes, and also inspire a greater transparency in the future use of NDBS samples.

Concentrations of perfluoroalkyl substances and bisphenol A in newborn dried blood spots and the association with child behavior

Experimental studies suggest that prenatal exposure to endocrine disrupting chemicals interferes with developmental processes in the fetal brain. Yet, epidemiological evidence is inconclusive.In a birth cohort (2008–2010, upstate New York), we quantified concentrations of perfluorooctane sulfonic acid (PFOS), perfluorooctanoic acid (PFOA), and bisphenol A (BPA) in stored newborn dried blood spots using liquid chromatography/tandem mass spectrometry. Mothers reported on children's behavior using the Strengths and Difficulties Questionnaire at age 7 (650 singletons and 138 twins). Difficulties in total behavior (i.e., emotional, conduct, hyperactivity, and peer problems) and prosocial behavior were classified using validated cut-offs. We used logistic regression with generalized estimating equations to estimate the odds of having difficulties per exposure category.In total, 111 children (12.1%) had total behavioral difficulties and 60 (6.5%) had difficulties in prosocial behavior. The median (interquartile range) of PFOS, PFOA, and BPA were 1.74 ng/ml (1.33), 1.12 ng/ml (0.96), and 7.93 ng/ml (10.79), respectively. Higher PFOS levels were associated with increased odds of having behavioral difficulties (OR per SD of log PFOS = 1.30, 95%CI: 1.03–1.65). We observed associations between PFOS in the highest relative to the lowest quartile and behavioral difficulties (OR for PFOS1.14-1.74 = 1.65, 95%CI: 0.84–3.34; PFOS1.75-2.47 = 1.73, 95%CI: 0.87–3.43; and PFOS>2.47 = 2.47, 95%CI: 1.29–4.72 compared to PFOS<1.41). The associations between higher concentrations of PFOS and behavioral difficulties at age 7 years were driven by problems in conduct and emotional symptoms. Higher PFOA levels were associated with difficulties in prosocial behavior (OR = 1.35, 95%CI: 1.03–1.75). There was an inverse association between BPA concentrations and difficulties in prosocial behavior but only in the 2nd and 4th quartiles. We found no interactions between sex and chemical concentrations.Increasing prenatal exposure to PFOS and PFOA, as reflected in neonatal concentrations, may pose risk for child behavioral difficulties.

Concentrations of Endocrine Disrupting Chemicals in Newborn Blood Spots and Early Development, Upstate Kids Study

Novel methods for quantifying chemicals in newborn dried bloodspots (NBS) allows researchers to directly measure exposures in children for examining impact on early development at the population level. We quantified three endocrine disrupting chemicals (EDCs) in NBS and assessed their associations with developmental screening results in the Upstate KIDS population-based birth cohort. The study included 2,049 singletons and 1,030 twins who were followed through age 3. The equivalent of one 16-mm circle was collected from stored NBS and measured for bisphenol A (BPA), perfluorooctanesulfonic acid (PFOS) and perfluorooctanoic acid (PFOA) &amp;lt;!--[endif]----&amp;gt;using high-performance liquid chromatography/tandem mass spectrometry with limits of detection of 0.30, 0.03 and 0.05 ng/mL, respectively. Parents completed 7 Ages and Stages Questionnaires&amp;#169; between 4 and 36 months of age for each child and results were calculated for failing any of five domains (fine and gross motor, communication, personal-social, problem solving). Using generalized linear mixed modeling techniques with log transformed EDCs, we estimated adjusted odds ratios (aOR) and 95% confidence intervals (CI) per standard deviation increase in log-transformed chemical concentrations. A second random intercept was included to account for clustering between twins from the same family. All models were adjusted for maternal age, education, and infertility treatment. The PFOS and PFOA median concentrations were 1.69 ng/ml (IQR: 1.11, 2.40) and 1.08 ng/ml (IQR: 0.67, 1.60), respectively and 7.89 ng/ml (IQR: 3.38, 14.56 ng/ml) for BPA. Among singletons, failing any domain was not associated with PFOS or PFOA (aOR: 0.89; 0.77-1.05 and aOR: 0.93;0.79-1.09 per SD increase in concentrations, respectively) or with BPA (aOR:1.04; 0.89-1.21). Results did not differ for twins. Using direct measures of EDCs in newborn infants, we observed no association with early development through age three.

Concentrations of Endocrine Disruptors in Newborn Dried Blood Spots and Child Behavior

Concentrations of Endocrine Disruptors in Newborn Dried Blood Spots and Child Behavior

Concentrations of endocrine disrupting chemicals in newborn blood spots and infant outcomes in the upstate KIDS study

BackgroundNovel methodologies to quantify infant exposures to endocrine disrupting chemicals (EDCs) for population-based studies are needed. ObjectivesWe used newborn dried blood spots to quantify three EDCs and their associations with infant outcomes in the Upstate KIDS Cohort. MethodsWe measured bisphenol A (BPA), perfluorooctanesulfonic acid (PFOS) and perfluorooctanoic acid (PFOA) in 2071 singleton and 1040 twin infants born to mothers in New York State. We log transformed concentrations after rescaling by their standard deviations and modeled each in relation to gestational age, birthweight, length, head circumference and Ponderal Index (PI) using linear regression techniques. All models were adjusted for maternal age, body mass index, education, infertility treatment and parity. Generalized estimating equations with robust standard errors were used to assess the associations for twins. ResultsChemicals were largely quantified above the limits of detection (>99% for PFOS and PFOA; 90% for BPA). Overall, we observed no significant associations between PFASs and birth size irrespective of plurality of birth. However, among twins, BPA was associated with decreases in gestational age (adjusted β = −0.09 weeks; 95% Confidence Interval (CI): −0.16, −0.02) and birthweight (adjusted β = −32.52 g; 95% CI: −60.99, −4.05), head circumference (adjusted β = −0.18 cm; 95% CI: −0.38, −0.02) and increased PI in singletons (adjusted β = 0.02 cm; 95% CI: 0.004, 0.04). ConclusionWe observed negative associations between BPA and birth size in twins. Our findings demonstrate the feasibility of newborn dried blood spots for quantifying neonatal exposure at the population level.

Diagnosis of niemann-pick C1 by measurement of bile acid biomarkers in archived newborn dried blood spots

BackgroundNiemann-Pick disease type C1 (NPC1) is a rare, neurodegenerative cholesterol storage disorder. Diagnostic delay of >5 years is common due to the rarity of the disease and non-specific early symptoms. To improve diagnosis and facilitate early intervention, we previously developed a newborn screening assay based on newly identified plasma bile acid biomarkers. Because the newborn screen had been validated using dried blood spots (DBS) from already diagnosed NPC1 patients, an unanswered question was whether the screen would be able to detect individuals with NPC1 at birth. MethodsTo address this critical question, we obtained the newborn DBS for already diagnosed NPC1 subjects (n = 15) and carriers (n = 3) residing in California, New York, and Michigan states that archive residual DBS in biorepositories. For each of the DBS, we obtained two neighbor controls – DBS from patients born on the same day and in the same hospital as the NPC1 patients and carriers. 3β,5α,6β-trihydroxycholanic acid (bile acid A) and trihydroxycholanic acid glycine conjugate (bile acid B) were measured in the DBS using a liquid chromatography-tandem mass spectrometry (LC-MS/MS) assay. ResultsBile acid B, the more specific biomarker for which the fully validated DBS assay was developed, was detected in 8/15 NPC1 patients, and elevated above the cut-off in 2/15 patients (the two samples with the shortest storage time). Bile acid B was detected in 2/2, 6/10, and 0/7 NPC1 samples that have been stored for <10.5 years, 13–20 years, and > 20 years, respectively, indicating that the glycine conjugate is detectable in DBS but may have reduced long-term stability compared with bile acid A, the precursor trihydroxycholanic acid, which was elevated in 15/15 NPC1 subjects, but not in carriers and controls. ConclusionsThese results demonstrate that newborn screening for NPC1 disease is feasible using bile acid biomarkers.

Postnatal Gestational Age Estimation Using Newborn Metabolic Profiles: A Validation Study in Matlab, Bangladesh

Background: Accurate preterm birth data are necessary for population health surveillance and to guide preterm birth initiatives. Gestational age is not routinely or accurately documented in many low-resource nations, however. Metabolic testing of newborn dried blood spots has been used to develop algorithms that yield accurate preterm birth estimates in North America. This study sought to validate published gestational age estimation models in infants born in Bangladesh. Methods: This was a prospective cohort study nested within the Preterm and Stillbirth Study, Matlab. The gestational age of all infants was confirmed by first trimester ultrasound. Cord blood and heel-prick blood spots were collected and analyzed at a provincial newborn screening facility in Ottawa, Canada. The performance of previously-published gestational age algorithms developed from heel-prick data to derive gestational age and preterm birth estimates was evaluated. Findings: 1036 cord blood and 487 heel-prick samples were collected from 1069 unique newborns. When applied to heel-prick metabolic profiles, published algorithms correctly estimated gestational age to within 1.07 weeks and accurately estimated gestational age to within 2 weeks for 94.3% of infants. Model performance was modestly reduced when applied to cord blood samples and accurately estimated gestational age to within 2 weeks for 90.3% of infants. Areas under the curve for distinguishing preterm births from term births were 0.945 (95%CI 0.890-0.999) for heel-prick samples and 0.894 (95%CI 0.853-0.935) for cord blood data. Interpretation: Metabolic gestational age dating provides accurate population-level estimates of gestational age and preterm birth burden. Models are effective on data obtained from both heel prick and cord blood, with the latter as a potentially more feasible option for deriving preterm birth estimates in low resource settings. Funding: This study was supported by the Bill & Melinda Gates Foundation [OPP1141535]. Declaration of Interest: The authors report no conflicts of interest Ethical Approval: Mothers provided informed consent for their infants to be included in the PreSSMat birth cohort and to have clinical data, cord blood and newborn heel prick samples collected and analysed. The present study was approved by the Research Review and Ethical Review Committees of the International Centre for Diarrhoeal Disease Research, Bangladesh (PR-16039). Approvals were also obtained from the Research Ethics Boards of the Ottawa Health Science Network (20160219-01H), and the Children’s Hospital of Eastern Ontario (16/20E).

Concentrations of immune marker in newborn dried blood spots and early childhood development: Results from the Upstate KIDS Study.

Evidence shows cytokine dysregulation in children with developmental disabilities. The association between immune activity during the perinatal period and child development is less clear. We examined the relationship between newborn concentrations of immune markers and child development. Within Upstate KIDS, a population-based birth cohort (2008-2010, upstate New York), we assayed immune markers, which are postulated to have neuro-modulatory effects, in newborn dried blood spots (NDBS, n=3038). Mothers completed the Ages & Stages Questionnaire© (ASQ) for their children repeatedly through age 36months. At 30 and 36months, mothers also reported whether their children received any developmental services. We used generalised linear mixed models adjusted for maternal and child characteristics to test associations. Sixteen immune markers were associated with failing ASQ in unadjusted models. After full adjustment (for gestational age, mode of delivery, parity, pregnancy smoking, etc.), we observed that higher levels of 4 markers, including platelet-derived growth factor-AA (PDGF-AA, OR 0.77, 95% CI 0.67, 0.89), plasminogen activator inhibitor-1 (OR 0.80, 95% CI 0.68, 0.94), stromal cell derived factor-1 (OR 0.85, 95% CI 0.73, 0.98), and macrophage inflammatory protein-1beta (OR 0.87, 95% CI 0.77, 0.98) were associated with lower odds of ASQ failure. The associations did not exist if correction for multiple comparisons was performed, except for PDGF-AA. Analyses with developmental service use revealed similar null findings. Immune marker concentrations in NDBS may not be associated with developmental delay in the general population. Newborn concentrations of growth factor PDGF-AA may be protective of developmental delay in childhood.

Metabolic profiles derived from residual blood spot samples: A longitudinal analysis

Background: Secondary use of newborn screening dried blood spot samples include use for biomedical or epidemiological research. However, the effects of storage conditions on archival samples requires further examination. The objective of this study was to determine the utility of residual newborn samples for deriving reliable metabolic gestational age estimates. Methods: Residual newborn dried blood spot samples that had been stored for 2-, 4-, 6-, or 12-months in temperature controlled (21°C) conditions were re-analyzed for the full panel of newborn screening analytes offered by a provincial newborn screening lab in Ottawa, Canada. Data from re-analyzed samples were compared to corresponding baseline newborn screening values for absolute agreement, and Pearson and intraclass correlation. Performance of a gestational age estimation algorithm originally developed from baseline newborn screening values was then validated on data derived from stored samples. Results: A total of 307 samples were used for this study. 17-hydroxyprogesterone and newborn hemoglobin profiles measured by immunoassay and high-performance liquid chromatography, respectively, were among the most stable markers across all time points of analysis. Acylcarnitines exhibited the greatest degree of variation in stability upon repeat measurement. The largest shifts in newborn analyte profiles and the poorest performance of metabolic gestational age algorithms were observed when samples were analyzed 12-months after sample collection. Conclusions: Duration of sample storage, independent of temperature and humidity, affects newborn screening profiles and gestational age estimates derived from metabolic gestational dating algorithms. When considering use of dried blood spot samples either for clinical or research purposes, care should be taken when interpreting data stemming from secondary use.

To PLEX or not to PLEX: Managing Hypertriglyceridemia-associated Pancreatitis

Improved second-tier tools are needed to reduce false-positive outcomes in newborn screening (NBS) for inborn metabolic disorders on the Recommended Universal Screening Panel (RUSP).We designed an assay for multiplex sequencing of 72 metabolic genes (RUSPseq) from newborn dried blood spots. Analytical and clinical performance was evaluated in 60 screen-positive newborns for methylmalonic acidemia (MMA) reported by the California Department of Public Health NBS program. Additionally, we trained a Random Forest machine learning classifier on NBS data to improve prediction of true and false-positive MMA cases.Of 28 MMA patients sequenced, we found two pathogenic or likely pathogenic (P/LP) variants in a MMA-related gene in 24 patients, and one pathogenic variant and a variant of unknown significance (VUS) in 1 patient. No such variant combinations were detected in MMA false positives and healthy controls. Random Forest–based analysis of the entire NBS metabolic profile correctly identified the MMA patients and reduced MMA false-positive cases by 51%. MMA screen-positive newborns were more likely of Hispanic ethnicity.Our two-pronged approach reduced false positives by half and provided a reportable molecular finding for 89% of MMA patients. Challenges remain in newborn metabolic screening and DNA variant interpretation in diverse multiethnic populations.

Metabolic profiles derived from residual blood spot samples: A longitudinal analysis.

Background: Secondary use of newborn screening dried blood spot samples include use for biomedical or epidemiological research. However, the effects of storage conditions on archival samples requires further examination. The objective of this study was to determine the utility of residual newborn samples for deriving reliable metabolic gestational age estimates. Methods: Residual newborn dried blood spot samples that had been stored for 2-, 4-, 6-, or 12-months in temperature controlled (21°C) conditions were re-analyzed for the full panel of newborn screening analytes offered by a provincial newborn screening lab in Ottawa, Canada. Data from re-analyzed samples were compared to corresponding baseline newborn screening values for absolute agreement, and Pearson and intraclass correlation. Performance of a gestational age estimation algorithm originally developed from baseline newborn screening values was then validated on data derived from stored samples. Results: A total of 307 samples were used for this study. 17-hydroxyprogesterone and newborn hemoglobin profiles measured by immunoassay and high-performance liquid chromatography, respectively, were among the most stable markers across all time points of analysis. Acylcarnitines exhibited the greatest degree of variation in stability upon repeat measurement. The largest shifts in newborn analyte profiles and the poorest performance of metabolic gestational age algorithms were observed when samples were analyzed 12-months after sample collection. Conclusions: Duration of sample storage, independent of temperature and humidity, affects newborn screening profiles and gestational age estimates derived from metabolic gestational dating algorithms. When considering use of dried blood spot samples either for clinical or research purposes, care should be taken when interpreting data stemming from secondary use.