Newborn Dried Blood Spots Research Articles

Metabolomic signatures associated with fetal growth restriction and small for gestational age: a systematic review.

The pathways involved in the pathophysiology of fetal growth restriction (FGR) and small for gestational age (SGA) are incompletely understood. We conduct a systematic review to identify metabolomic signatures in maternal and newborn tissues and body fluids samples associated with FGR/SGA. Here, we report that 825 non-duplicated metabolites were significantly altered across the 48 included studies using 10 different human biological samples, of which only 56 (17 amino acids, 12 acylcarnitines, 11 glycerophosphocholines, six fatty acids, two hydroxy acids, and eight other metabolites) were significantly and consistently up- or down-regulated in more than one study. Three amino acid metabolism-related pathways and one related with lipid metabolism are significantly associated with FGR and/or SGA: biosynthesis of unsaturated fatty acids in umbilical cord blood, and phenylalanine, tyrosine and tryptophan biosynthesis, valine, leucine and isoleucine biosynthesis, and phenylalanine metabolism in newborn dried blood spot. Significantly enriched metabolic pathways were not identified in the remaining biological samples. Whether these metabolites are in the causal pathways or are biomarkers of fetal nutritional deficiency needs to be explored in large, well-phenotyped cohorts.

The association of maternal COVID-19-infection during pregnancy on the neonatal immune profile and associations with later diagnosis of neurodevelopmental disorders

Despite the prevalence and significant concern of COVID-19 in maternal and offspring health, little is known about the impact of COVID-19 during pregnancy on newborn immunity and neurodevelopment. This study aimed to examine 1) the relationship between maternal COVID-19 during pregnancy and newborn immune profiles and investigate the 2) associations between specific newborn immune profiles and the risk of subsequent diagnosis of a neurodevelopmental disorder (NDD) among children with prenatal exposure to COVID-19. Newborn dried bloodspots (NBS) from 545 children born at Kaiser Permanente Northern California between January 2020 and September 2021 (460 [223 males, 237 females] to COVID-19-infected [COVID + ] mothers; 85 [45 males, 40 females] to COVID-19-uninfected [COVID-] mothers) were used to profile newborn immune molecules via a 42-plex cytokine/chemokine assay. Among the 460 children born to COVID + mothers, 73 (47 males, 27 females) were later diagnosed with an NDD. In the first set of analyses examining the association between maternal COVID-19 infection during pregnancy and newborn immune profile, the results adjusted for covariates but uncorrected for multiple comparisons showed that newborns of COVID + mothers had significantly higher levels of IL-22 (est. = 0.16, 95 % Cl 0.01, 0.3, p = 0.04) and GM-CSF (estimate [est.] = 0.27, 95 % Cl 0.09, 0.46, p = 0.004) compared to newborns of COVID- mothers. These differences were no longer statistically significant after multiple comparison adjustments. In the second analysis exploring the association between newborn profile and later diagnosis of NDD among newborns born to COVID + mothers, the results adjusted for covariates revealed an association between higher neonatal levels of IL-22 (HR = 0.49, 95 % Cl 0.33, 0.75, p = 0.001) and lower risk of a later diagnosis of an NDD, which remained significant after multiple comparison adjustments (p = 0.04). Other neonatal cytokines/chemokines/growth factors such as sCD40L (HR = 0.7, 95 % Cl 0.57, 0.9, p = 0.009), IP-10 (HR = 0.46, 95 % Cl 0.25, 0.83, p = 0.009), MIG (HR = 0.52, 95 % Cl 0.3, 0.9, p = 0.02), FLT-3L (HR = 0.45, 95 % Cl 0.24, 0.83, p = 0.01), PDGF AB/BB (HR = 0.56, 95 % Cl 0.36, 0.99, p = 0.046), VEGF (HR = 0.57, 95 % Cl 0.34, 0.98, p = 0.04), and IL-4 (HR = 0.48, 95 % Cl 0.26, 0.93, p = 0.03) were no longer statistically significant after multiple comparison adjustments. Despite the imbalance between the number of COVID-19 exposed and unexposed newborns in this study cohort, our novel findings enhance our understanding of the potential impact of maternal COVID-19 infection during pregnancy on the developing neonatal immune system. Our findings highlight the role of immune molecules, beyond those considered to be pro-inflammatory, that may be crucial in maternal and newborn immunity against COVID-19 infection during pregnancy. Furthermore, our results suggest that reduced levels of neonatal immune molecules in newborns of COVID + mothers may be linked to an increased risk of a subsequent diagnosis of an NDD.

A Prospective Analysis of Per- and Polyfluoroalkyl Substances from Early Pregnancy to Delivery in the Atlanta African American Maternal-Child Cohort.

Longitudinal trends in per- and polyfluoroalkyl substances (PFAS) serum concentrations across pregnancy have not been thoroughly examined, despite evidence linking prenatal PFAS exposures with adverse birth outcomes. We sought to characterize longitudinal PFAS concentrations across pregnancy and to examine the maternal-fetal transfer ratio among participants in a study of risk and protective factors for adverse birth outcomes among African Americans. In the Atlanta African American Maternal-Child cohort (2014-2020), we quantified serum concentrations of four PFAS in 376 participants and an additional eight PFAS in a subset of 301 participants during early (8-14 weeks gestation) and late pregnancy (24-30 weeks gestation). Among these, PFAS concentrations were also measured among 199 newborns with available dried blood spot (DBS) samples. We characterized the patterns, variability, and associations in PFAS concentrations at different time points across pregnancy using intraclass correlation coefficients (ICCs), maternal-newborn pairs transfer ratios, linear mixed effect models, and multivariable linear regression, adjusting for socioeconomic and prenatal predictors. Perfluorohexane sulfonic acid (PFHxS), perfluorooctane sulfonic acid (PFOS), perfluorooctanoic acid (PFOA), and perfluorononanoic acid (PFNA) were detected in of maternal samples, with PFHxS and PFOS having the highest median concentrations. We observed high variability in PFAS concentrations across pregnancy time points (). All median PFAS concentrations increased from early to late pregnancy, except for PFOA and N-methyl perfluorooctane sulfonamido acetic acid (NMFOSAA), which decreased [paired -test for all PFAS except for PFOA and perfluorobutane sulfonic acid (PFBS)]. Prenatal serum PFAS were weakly to moderately correlated with newborn DBS PFAS ( ). The median maternal-fetal PFAS transfer ratio was lower for PFAS with longer carbon chains. After adjusting for socioeconomic and prenatal predictors, in linear mixed effect models, the adjusted mean PFAS concentrations significantly increased during pregnancy, except for PFOA. In multivariable linear regression, PFAS concentrations in early pregnancy significantly predicted the PFAS concentrations in late pregnancy and in newborns. We found that the concentrations of most PFAS increased during pregnancy, and the magnitude of variability differed by individual PFAS. Future studies are needed to understand the influence of within-person PFAS variability during and after pregnancy on birth outcomes. https://doi.org/10.1289/EHP14334.

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.

Latent profile analysis of newborn dried blood spot (DBS) cyto-and chemo-kines and growth factors and maternal and fetal acute inflammatory responses to amniotic fluid infection.

Latent profile analysis of newborn dried blood spot (DBS) cyto-and chemo-kines and growth factors and maternal and fetal acute inflammatory responses to amniotic fluid infection.

Newborn Dried Blood Spot Folate in Relation to Maternal Self-reported Folic Acid Intake, Autism Spectrum Disorder, and Developmental Delay.

Maternal folic acid intake has been associated with decreased risk for neurodevelopmental disorders including autism spectrum disorder (ASD). Genetic differences in folate metabolism could explain some inconsistencies. To our knowledge, newborn folate concentrations remain unexamined. We measured folate in archived newborn dried blood spots of children from the CHARGE (Childhood Autism Risks from Genetics and the Environment) case-control study who were clinically confirmed at 24-60 months to have ASD (n = 380), developmental delay (n = 128), or typical development (n = 247). We quantified monthly folic acid intake from maternally-reported supplements and cereals consumed during pregnancy and 3 months prior. We assessed associations of newborn folate with maternal folic acid intake and with ASD or developmental delay using regression. We stratified estimates across maternal and child MTHFR genotypes. Among typically developing children, maternal folic acid intake in prepregnancy and each pregnancy month and prepregnancy prenatal vitamin intake were positively associated with newborn folate. Among children with ASD, prenatal vitamin intake in pregnancy months 2-9 was positively associated with newborn folate. Among children with developmental delay, maternal folic acid and prenatal vitamins during the first pregnancy month were positively associated with neonatal folate. Associations differed by MTHFR genotype. Overall, neonatal folate was not associated with ASD or developmental delay, though we observed associations with ASD in children with the MTHFR 677 TT genotype (odds ratio: 1.76, 95% CI = 1.19, 2.62; P for interaction = 0.08). Maternal prenatal folic acid intake was associated with neonatal folate at different times across neurodevelopmental groups. Neonatal folate was not associated with reduced ASD risk. MTHFR genotypes modulated these relationships.

Tandem mass spectrometric enzyme assay for simultaneous detection of Tay-Sachs and Sandhoff diseases in dried blood spots for newborn screening

GM2 gangliosidosis is a group of rare lysosomal storage disorders (LSDs) including Tay-Sachs disease (TSD) and Sandhoff disease (SD), caused by deficiency in activity of either β-hexosaminidase A (HexA) or both β-hexosaminidase A and β-hexosaminidase B (Hex B). Methods for screening and diagnosis of TSD and SD include measurement and comparison of the activity of these two enzymes. Here we report a novel method for duplex screening of dried blood spots (DBS) for TSD and SD by liquid chromatography-tandem mass spectrometry (LC-MS/MS). The method requires incubation of a single 3 mm DBS punch with the assay cocktail followed by the injection into the LC-MS/MS. The performance of the method was evaluated by comparing the confirmed TSD and SD patient DBS to random healthy newborn DBS which showed easy discrimination between the three cohorts. The method is multiplexable with other LSD MS/MS enzyme assays which is critical to the continued expansion of the NBS panels.

Proposed Screening for Congenital Hyperinsulinism in Newborns: Perspective from a Neonatal-Perinatal Medicine Group.

This perspective work by academic neonatal providers is written specifically for the audience of newborn care providers and neonatologists involved in neonatal hypoglycemia screening. Herein, we propose adding a screen for congenital hyperinsulinism (CHI) by measuring glucose and ketone (i.e., β-hydroxybutyrate (BOHB)) concentrations just prior to newborn hospital discharge and as close to 48 h after birth as possible, at the same time that the mandated state Newborn Dried Blood Spot Screen is obtained. In the proposed protocol, we do not recommend specific metabolite cutoffs, as our primary objective is to simply highlight the concept of screening for CHI in newborns to newborn caregivers. The premise for our proposed screen is based on the known effect of hyperinsulinism in suppressing ketogenesis, thereby limiting ketone production. We will briefly discuss genetic CHI, other forms of neonatal hypoglycemia, and their shared mechanisms; the mechanism of insulin regulation by functional pancreatic islet cell membrane KATP channels; adverse neurodevelopmental sequelae and brain injury due to missing or delaying the CHI diagnosis; the principles of a good screening test; how current neonatal hypoglycemia screening programs do not fulfill the criteria for being effective screening tests; and our proposed algorithm for screening for CHI in newborns.

Higher precision, first tier newborn screening for metachromatic leukodystrophy using 16:1-OH-sulfatide

Newborn screening (NBS) for metachromatic leukodystrophy (MLD) is based on first-tier measurement of sulfatides in dried blood spots (DBS) followed by second-tier measurement of arylsulfatase A in the same DBS. This approach is very precise with 0–1 false positives per ∼30,000 newborns tested. Recent data reported here shows that the sulfatide molecular species with an α-hydroxyl, 16‑carbon, mono-unsaturated fatty acyl group (16:1-OH-sulfatide) is superior to the original biomarker 16:0-sulfatide in reducing the number of first-tier false positives. This result is consistent across 4 MLD NBS centers. By measuring 16:1-OH-sulfatide alone or together with 16:0-sulfatide, the estimated false positive rate is 0.048% and is reduced essentially to zero with second-tier arylsulfatase A activity assay. The false negative rate is predicted to be extremely low based on the demonstration that 40 out of 40 newborn DBS from clinically-confirmed MLD patients are detected with these methods. The work shows that NBS for MLD is extremely precise and ready for deployment. Furthermore, it can be multiplexed with several other inborn errors of metabolism already tested in NBS centers worldwide.

Droplet Digital PCR (ddPCR) Does Not Enhance the Sensitivity of Detection of Cytomegalovirus (CMV) DNA in Newborn Dried Blood Spots Evaluated in the Context of Newborn Congenital CMV (cCMV) Screening.

Congenital cytomegalovirus (cCMV) infection is a leading cause of sensorineural hearing loss (SNHL) and neurodevelopmental disabilities in children worldwide. Some regions in the United States and Canada have implemented universal newborn screening for cCMV, which requires molecular diagnostic technologies for identifying cCMV, such as PCR testing of newborn dried blood spots (DBS). This study aimed to evaluate the sensitivity of droplet digital PCR (ddPCR) compared to quantitative real-time PCR to detect CMV DNA in newborn DBS. The limit of detection of various ddPCR primer/probe combinations (singleplex UL55-HEX, singleplex UL83-FAM, and multiplex UL55-HEX/UL83-FAM) was evaluated using the National Institute of Standards and Technology's (NIST) CMV quantitative standard. Singleplex UL55-HEX ddPCR exhibited the lowest limit of detection among the primer/probe combinations tested for ddPCR. UL55 ddPCR was then compared to real-time PCR in 49 infants with confirmed cCMV identified through newborn screening for CMV in saliva swabs and confirmed by a urine test. The results showed that ddPCR was only positive for 59% (29 out of 49) of the cCMV infants, while real-time PCR was positive for 80% (39 out of 49). Due to its lower sensitivity and throughput, ddPCR may not be suitable for cCMV newborn screening.

Exposure to persistent organic pollutants in newborn dried blood spots and childhood acute myeloid leukemia

Acute myeloid leukemia (AML) is a rare malignancy representing 15–20% of all leukemia diagnoses among children. Maternal exposure to persistent organic pollutants is suggestive of increased risk for childhood AML based on existing evidence. We aimed to evaluate the relationship between persistent organic pollutants and childhood AML using newborn dried bloodspots (DBS) from the Michigan BioTrust for Health. We obtained data on AML cases diagnosed prior to 15 years of age (n = 130) and controls (n = 130) matched to cases on week of birth from the Michigan Department of Health and Human Services. We quantified levels of dichlorodiphenyldichloroethylene (p,p’-DDE), hexachlorobenzene (HCB), and polybrominated diphenyl ether congener 47 (BDE-47) in newborn DBS. We also evaluated other organochlorine pesticides, polychlorinated biphenyls, polybrominated biphenyl congener 153, and polybrominated diphenyl ethers, though these were not further evaluated as >60% of observations were above the limit of detection for these chemicals. To evaluate the association between each chemical and AML, we used multivariable conditional logistic regression. In our multivariable model of HCB adjusted for month of birth, maternal age at delivery, and area poverty, we observed no association with AML (Odds Ratio [OR] per interquartile range increase: 1.17, 95% CI: 0.80, 1.69). For p,p’-DDE, ORs were significantly lower for those exposed to the highest tertile of p,’p-DDE (≥0.29 pg/mL, OR: 0.32, 95% CI: 0.11, 0.95) compared to the first tertile (<0.09 pg/mL). We observed no statistically significant associations between HCB and BDE-47 and AML. We observed a reduced odds of exposure to p,’p-DDE and an increased, though imprecise, odds of exposure to HCB among AML cases compared to controls. Future studies would benefit from a larger sample of AML patients and pooling newborn DBS across multiple states to allow for additional variability in exposures and evaluation of AML subtypes, which may have differing etiology.

Advances in the Use of Residual Newborn Dried Blood Spots Within Environmental Epidemiology

Advances in the Use of Residual Newborn Dried Blood Spots Within Environmental Epidemiology

Abstract 15499: Biochemical and Genetic Newborn Screening for Familial Hypercholesterolemia

Introduction: Familial Hypercholesterolemia (FH) causes elevated low-density lipoprotein cholesterol (LDL-C) and premature atherosclerosis. Despite guidelines, universal screening rates remain low. Newborn screening could increase FH diagnostic rates. Hypothesis: FH can be diagnosed from newborn dried blood spots for LDL-C, total cholesterol (TC), and apolipoprotein B (apoB), followed by selective genetic testing to identify pathogenic and likely pathogenic variants causing FH. Methods: De-identified, residual newborn screening dried blood spots were analyzed for LDL-C, TC, and apoB with results expressed as multiples of the median (MoM). Mahalanobis distance (measuring MoM different from 1) was computed and the top 8% of distances selected for genetic testing (panel including LDLR , APOB , PCSK9 , LDLRAP1 , APOE , LIPA , ABCG5 , and ABCG8 ). Results: A total of 10,004 specimens had biochemical testing, with 768 specimens selected for genetic testing. In total 15 variants were identified, 11 pathogenic and 4 likely pathogenic (Table 1). Composite Mahalanobis distance from LDL-C and apoB identified the most variants, followed by apoB alone and then LDL-C alone. TC alone identified the fewest number of variants (Table 2). Conclusions: Testing newborn dried blood spots with biochemical and reflex genetic testing is feasible to detect FH. Genetic testing of about 8% of samples identified 1 in 667 newborns with FH, but more extensive genetic testing would likely detect more variants. Prospective studies are needed to correlate newborn results with LDL-C levels later in childhood.

One-step NGS molecular analysis of the CFTR gene on newborn dried blood spots gives a higher diagnostic sensitivity in affected and carrier subjects: A pilot study

BackgroundCystic fibrosis is the most common hereditary recessive disease with an incidence of about 1:2500/3000. It has long been known that the disease is caused by deleterious mutations in the CFTR gene. Conventionally, the disease is diagnosed in several phases. The analysis of all the possible disease-causing molecular alterations is time consuming and may not lead to a definitive diagnosis in several cases. Consequently, we propose, in this paper, a rapid sequencing method that, in a single procedural asset, reveals the presence of small mutations and also the copy number variants (CNVs) from the DNA extracted from the Guthrie Spot. Materials and MethodsWe first sequenced 30 blood spots, then we validated the method on 100 spots that underwent both traditional analyses and this complete NGS sequencing, and lastly, we tested the strategy on patients who normally do not reach the molecular sequencing step because of low level of Immune-Reactive Trypsinogen. ResultsUsing this procedure, we identified 97 variants in the CFTR gene of our samples and 6 CNVs. Notably, the significant data were obtained in the group of patients with borderline or negative IRT who routinely would not undergo molecular testing. We also identified 6 carriers of “disease-causing” variants. ConclusionThis method is very robust. Indeed, there was a 100% concordance with Sanger sequencing validation, and 6 mutation carriers were identified who normally escaped molecular testing with actual conventional procedure. There were also 3 duplications of almost the entire gene in heterozygosity, which were not seen with traditional methods. Being quick and easy to perform, we suggest that complete sequencing of the CFTR gene, as in this study be considered for all newborns.

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

PurposeCurrent and emerging treatments for Duchenne muscular dystrophy (DMD) position DMD as a candidate condition for newborn screening (NBS). In anticipation of the nomination of DMD for universal NBS, we conducted a prospective study under the Early Check voluntary NBS research program in North Carolina, United States. MethodsWe performed screening for creatine kinase-MM (CK-MM), a biomarker of muscle damage, on residual routine newborn dried blood spots (DBS) from participating newborns. Total creatine kinase testing and next generation sequencing of an 86-neuromuscular gene panel that included DMD were offered to parents of newborns who screened positive. Bivariate and multivariable analyses were performed to assess effects of biological and demographic predictors on CK-MM levels in DBS. ResultsWe screened 13,354 newborns and identified 2 males with DMD. The provisional 1626 ng/mL cutoff was raised to 2032 ng/mL to improve specificity, and additional cutoffs (900 and 360 ng/mL) were implemented to improve sensitivity for older and low-birthweight newborns. ConclusionPopulation-scale screening for elevated CK-MM in DBS is a feasible approach to identify newborns with DMD. Inclusion of birthweight- and age-specific cutoffs, repeat creatine kinase testing after 72 hours of age, and DMD sequencing improve sensitivity and specificity of screening.

Epigenomic signature of major congenital heart defects in newborns with Down syndrome

BackgroundCongenital heart defects (CHDs) affect approximately half of individuals with Down syndrome (DS), but the molecular reasons for incomplete penetrance are unknown. Previous studies have largely focused on identifying genetic risk factors associated with CHDs in individuals with DS, but comprehensive studies of the contribution of epigenetic marks are lacking. We aimed to identify and characterize DNA methylation differences from newborn dried blood spots (NDBS) of DS individuals with major CHDs compared to DS individuals without CHDs.MethodsWe used the Illumina EPIC array and whole-genome bisulfite sequencing (WGBS) to quantitate DNA methylation for 86 NDBS samples from the California Biobank Program: (1) 45 DS-CHD (27 female, 18 male) and (2) 41 DS non-CHD (27 female, 14 male). We analyzed global CpG methylation and identified differentially methylated regions (DMRs) in DS-CHD versus DS non-CHD comparisons (both sex-combined and sex-stratified) corrected for sex, age of blood collection, and cell-type proportions. CHD DMRs were analyzed for enrichment in CpG and genic contexts, chromatin states, and histone modifications by genomic coordinates and for gene ontology enrichment by gene mapping. DMRs were also tested in a replication dataset and compared to methylation levels in DS versus typical development (TD) WGBS NDBS samples.ResultsWe found global CpG hypomethylation in DS-CHD males compared to DS non-CHD males, which was attributable to elevated levels of nucleated red blood cells and not seen in females. At a regional level, we identified 58, 341, and 3938 CHD-associated DMRs in the Sex Combined, Females Only, and Males Only groups, respectively, and used machine learning algorithms to select 19 Males Only loci that could distinguish CHD from non-CHD. DMRs in all comparisons were enriched for gene exons, CpG islands, and bivalent chromatin and mapped to genes enriched for terms related to cardiac and immune functions. Lastly, a greater percentage of CHD-associated DMRs than background regions were differentially methylated in DS versus TD samples.ConclusionsA sex-specific signature of DNA methylation was detected in NDBS of DS-CHD compared to DS non-CHD individuals. This supports the hypothesis that epigenetics can reflect the variability of phenotypes in DS, particularly CHDs.

Gene-Environment Analyses Reveal Novel Genetic Candidates with Prenatal Tobacco Exposure in Relation to Risk for Childhood Acute Lymphoblastic Leukemia.

Associations between maternal tobacco exposure during pregnancy and childhood acute lymphoblastic leukemia (ALL) have yielded mixed results. This may be due to biases in self-reported smoking or other differences in individual-level risk factors. We utilized a biological marker of maternal tobacco exposure to evaluate the association between maternal tobacco exposure during pregnancy, genetics, and subsequent childhood ALL risk in two large population-based studies of childhood ALL in California. Maternal exposure to tobacco smoke was assessed with a validated methylation marker (cg05575921) of the aryl hydrocarbon receptor repressor (AHRR) gene in newborn dried blood spots. We adjusted for sex, birthweight, gestational age, mode of delivery, year of birth, AHRR quantitative trait locus (mQTL) rs77111113, and a polygenetic risk score for childhood ALL. We additionally adjusted for principal components in a gene-environment interaction testing method that incorporates gene-only and environment-only effects along with interactions. AHRR hypomethylation overall was not associated with childhood ALL. In gene-environment interaction testing, several genetic variants displayed significant interaction with AHRR hypomethylation and childhood ALL. Our results suggest that novel candidates in PTPRK and DPP6 may play a role in tobacco-related leukemogenesis. Further research is necessary to better understand the effects of tobacco and these variants on childhood ALL risk. Despite the lack of an overall "main effect," tobacco exposure during pregnancy affects childhood ALL risk depending on specific genetic variants.

B-263 Molecular Assay Evaluation to SMA and SCID Diagnosis in Newborn Dried Blood Spots (DBS)

Abstract Background Spinal muscular atrophy (SMA) is a neurodegenerative disease caused by insufficient levels of the survival motor neuron (SMN) protein. Almost 95% of SMA cases are caused by the homozygous deletion involving exon 7 of the SMN1 gene. Its incidence is estimated in 1:6000–11 800 live births and it is the most common genetic cause of death in infancy. Symptoms of SMA include several cognitive disabilities leading to death, due to loss of motor functions, rapid denervation, and progressive weakening. In addition, another very common syndrome among newborns is Severe Combined Immunodeficiency (SCID). SCID is a genetic disease that may compromise the Lymphocytes T, B, and/or Natural Killers cells functions causing repeated and persistent infections. Low levels of the recombination excision circles of T and B cells (TREC and KREC, respectively) are indicative of SCID or other lymphopenias. Due to the early onset and rapid progression of SMA and SCID, accurate diagnosis of these syndromes is of utmost importance to perform therapeutic intervention before the onset of symptoms. Therefore, this study aims to describe the analytical and clinical validation of a kit for the implementation of a multiplex SCID/SMA real-time diagnoses routine in dried blood spots (DBS). Methods Commercial quantified positive control and samples were used for the analytical and clinical validation, respectively. The Clinical validation included 67 samples with the SMN1 gene and 7 samples with gene deletion. For the SCID evaluation, 60 samples with normal levels of TREC and KREC and 11 samples with reduced levels were included. DNA isolation was performed with the DNA Extract All Reagents Kit (Thermo Fisher, Massachusetts, EUA) from a 3.2mm disc of newborn DBS. The qPCR assay was performed by the TaqMan SCID/SMA Plus Assay (Thermo Fisher, Massachusetts, EUA) to target TREC, KREC, and SMN1 according to the manufacturer's instructions. The analysis parameters included: (i) Determination of assay efficiency; (ii) Analytical sensitivity (Limit of detection); (iii) Intra-assay and inter-assay precision; and (iv) Clinical validation. All reactions included the endogenous control RNase P. Results The assay demonstrated reaction efficiency &amp;gt;98% and the limit of detection was 30 copies per reaction for TREC, KREC, and SMN1 targets with a 95% confidence interval. The regression equations demonstrated good amplification conditions with a coefficient of determination (r2) = 0.99. The precision experiments demonstrated optimal repeatability and reproducibility. The results obtained in the clinical validation showed 100% agreement with the expected results for the SMN1 target. To the TREC and KREC targets, the assay demonstrated 95% and 100% agreement for normal and reduced levels, respectively. Conclusion An accurate and rapid diagnosis is essential to guide the clinical management of SCID and SMA in newborns. Here, we evaluated and described the TaqMan SCID/SMA Plus Assay performance, a molecular test for detecting SCID and SMA by Quantitative Real-time PCR (qPCR). This assay was highly efficient due offer of a multiplex detection method, allowing the rapid release of results. The use of this tool can help clinicians in rapid newborn screening, providing agility in clinical conduct.

Does reduced placental villous packing density, a marker of decreased numbers of terminal villi, demonstrate effects on cyto- and chemo-kine levels in newborn dried blood spots?

Does reduced placental villous packing density, a marker of decreased numbers of terminal villi, demonstrate effects on cyto- and chemo-kine levels in newborn dried blood spots?

Per- and polyfluoroalkyl substances (PFAS) and thyroid hormone measurements in dried blood spots and neonatal characteristics: a pilot study

BackgroundPediatric thyroid diseases have been increasing in recent years. Environmental risk factors such as exposures to chemical contaminants may play a role but are largely unexplored. Archived neonatal dried blood spots (DBS) offer an innovative approach to investigate environmental exposures and effects.ObjectiveIn this pilot study, we applied a new method for quantifying per- and polyfluoroalkyl substances (PFAS) to 18 archived DBS from babies born in California from 1985–2018 and acquired thyroid hormone measurements from newborn screening tests. Leveraging these novel data, we evaluated (1) changes in the concentrations of eight PFAS over time and (2) the relationship between PFAS concentrations, thyroid hormone concentrations, and neonatal characteristics to inform future research.MethodsPFAS concentrations in DBS were measured using ultra-high-performance liquid chromatography-mass spectrometry. Summary statistics and non-parametric Wilcoxon rank-sum and Kruskal–Wallis tests were used to evaluate temporal changes in PFAS concentrations and relationships between PFAS concentrations, thyroid hormone concentrations, and neonatal characteristics.ResultsThe concentration and detection frequencies of several PFAS (PFOA, PFOS, and PFOSA) declined over the assessment period. We observed that the timing of specimen collection in hours after birth was related to thyroid hormone but not PFAS concentrations, and that thyroid hormones were related to some PFAS concentrations (PFOA and PFOS).Impact statementThis pilot study examines the relationship between concentrations of eight per- and polyfluoroalkyl substances (PFAS), thyroid hormone levels, and neonatal characteristics in newborn dried blood spots (DBS) collected over a period of 33 years. To our knowledge, 6 of the 22 PFAS we attempted to measure have not been quantified previously in neonatal DBS, and this is the first study to examine both PFAS and thyroid hormone concentrations using DBS. This research demonstrates the feasibility of using newborn DBS for quantifying PFAS exposures in population-based studies, highlights methodological considerations in the use of thyroid hormone data for future studies using newborn DBS, and indicates potential relationships between PFAS concentrations and thyroid hormones for follow-up in future research.