Lentiviral Gene Therapy for Artemis-Deficient SCID.

BACKGROUND: The DNA-repair enzyme Artemis is essential for rearrangement of T- and B-cell receptors. Mutations in DCLRE1C, which encodes Artemis, cause Artemis-deficient severe combined immunodeficiency (ART-SCID), which is poorly responsive to allogeneic hematopoietic-cell transplantation. METHODS: We carried out a phase 1-2 clinical study of the transfusion of autologous CD34+ cells, transfected with a lentiviral vector containing DCLRE1C, in 10 infants with newly diagnosed ART-SCID. We followed them for a median of 31.2 months. RESULTS: Marrow harvest, busulfan conditioning, and lentiviral-transduced CD34+ cell infusion produced the expected grade 3 or 4 adverse events. All the procedures met prespecified criteria for feasibility at 42 days after infusion. Gene-marked T cells were detected at 6 to 16 weeks after infusion in all the patients. Five of 6 patients who were followed for at least 24 months had T-cell immune reconstitution at a median of 12 months. The diversity of T-cell receptor ß chains normalized by 6 to 12 months. Four patients who were followed for at least 24 months had sufficient B-cell numbers, IgM concentration, or IgM isohemagglutinin titers to permit discontinuation of IgG infusions. Three of these 4 patients had normal immunization responses, and the fourth has started immunizations. Vector insertion sites showed no evidence of clonal expansion. One patient who presented with cytomegalovirus infection received a second infusion of gene-corrected cells to achieve T-cell immunity sufficient for viral clearance. Autoimmune hemolytic anemia developed in 4 patients 4 to 11 months after infusion; this condition resolved after reconstitution of T-cell immunity. All 10 patients were healthy at the time of this report. CONCLUSIONS: Infusion of lentiviral gene-corrected autologous CD34+ cells, preceded by pharmacologically targeted low-exposure busulfan, in infants with newly diagnosed ART-SCID resulted in genetically corrected and functional T and B cells. (Funded by the California Institute for Regenerative Medicine and the National Institute of Allergy and Infectious Diseases; ClinicalTrials.gov number, NCT03538899.).

Newborn screening for neurodevelopmental diseases: Are we there yet?

In the US, newborn screening (NBS) is a unique health program that supports health equity and screens virtually every baby after birth, and has brought timely treatments to babies since the 1960's. With the decreasing cost of sequencing and the improving methods to interpret genetic data, there is an opportunity to add DNA sequencing as a screening method to facilitate the identification of babies with treatable conditions that cannot be identified in any other scalable way, including highly penetrant genetic neurodevelopmental disorders (NDD). However, the lack of effective dietary or drug-based treatments has made it nearly impossible to consider NDDs in the current NBS framework, yet it is anticipated that any treatment will be maximally effective if started early. Hence there is a critical need for large scale pilot studies to assess if and how NDDs can be effectively screened at birth, if parents desire that information, and what impact early diagnosis may have. Here we attempt to provide an overview of the recent advances in NDD treatments, explore the possible framework of setting up a pilot study to genetically screen for NDDs, highlight key technical, practical, and ethical considerations and challenges, and examine the policy and health system implications.

SCID newborn screening: What we've learned.

Newborn screening for severe combined immunodeficiency, the most profound form of primary immune system defects, has long been recognized as a measure that would decrease morbidity and improve outcomes by helping patients avoid devastating infections and receive prompt immune-restoring therapy. The T-cell receptor excision circle test, developed in 2005, proved to be successful in pilot studies starting in the period 2008 to 2010, and by 2019 all states in the United States had adopted versions of it in their public health programs. Introduction of newborn screening for severe combined immunodeficiency, the first immune disorder accepted for population-based screening, has drastically changed the presentation of this disorder while providing important lessons for public health programs, immunologists, and transplanters.

NaCl aggregation in water at elevated temperatures and pressures: Comparison of classical force fields.

The properties of water vary dramatically with temperature and density. This can be exploited to control its effectiveness as a solvent. Thus, supercritical water is of keen interest as solvent in many extraction processes. The low solubility of salts in lower density supercritical water has even been suggested as a means of desalination. The high temperatures and pressures required to reach supercritical conditions can present experimental challenges during collection of required physical property and phase equilibria data, especially in salt-containing systems. Molecular simulations have the potential to be a valuable tool for examining the behavior of solvated ions at these high temperatures and pressures. However, the accuracy of classical force fields under these conditions is unclear. We have, therefore, undertaken a parametric study of NaCl in water, comparing several salt and water models at 200 bar-600 bar and 450 K-750 K for a range of salt concentrations. We report a comparison of structural properties including ion aggregation, hydrogen bonding, density, and static dielectric constants. All of the force fields qualitatively reproduce the trends in the liquid phase density. An increase in ion aggregation with decreasing density holds true for all of the force fields. The propensity to aggregate is primarily determined by the salt force field rather than the water force field. This coincides with a decrease in the water static dielectric constant and reduced charge screening. While a decrease in the static dielectric constant with increasing NaCl concentration is consistent across all model combinations, the salt force fields that exhibit more ionic aggregation yield a slightly smaller dielectric decrement.

Twin chorionicity and zygosity both vary with maternal age.

Objective: To determine the ratio of dichorionic (DC) to monochorionic (MC) twins by maternal age. Methods: We reviewed all twin pregnancies undergoing first trimester screening (FTS) with nuchal translucency from April 2009 to December 2012 with sonographic determination of chorionicity. Cases were linked to newborn screening (NBS) results and zygosity estimated based on rates of fetal sex discordance. The ratio of DC to MC placentation by maternal age was calculated. Results: We identified 11,351 twin pregnancies with FTS and documented chorionicity. Among these, 7,861 (64.2%) had linked data on FTS and NBS to allow estimation of zygosity based on neonatal sex. Of these, 1,464 (18.6%) were MC and 6,406 (81.4%) DC. The MC twin rate remained constant while the DC twin rate increased with maternal age until 40y. At < 20y, 55% of twin pregnancies were monozygotic (MZ), as compared to 29% at ≥ 40y. Of MZ twins, 38% were DC at < 20y, while 53% were DC at ≥ 40y. Conclusions: Our data suggest a relationship of both zygosity and chorionicity with maternal age. DZ twinning increased with maternal age, while among MZ twins, the proportion that were DC also increased with maternal age.

Thermodynamics, dynamics, and structure of supercritical water at extreme conditions.

Molecular dynamics (MD) simulations to understand the thermodynamic, dynamic, and structural changes in supercritical water across the Frenkel line and the melting line have been performed. The two-phase thermodynamic model [J. Phys. Chem. B, 2010, 114(24), 8191-8198] and the velocity autocorrelation functions are used to locate the Frenkel line and to calculate the thermodynamic and dynamic properties. The Frenkel lines obtained from the two-phase thermodynamic model and the velocity autocorrelation criterion do not agree with each other. Structural characteristics and the translational diffusion dynamics of water suggest that this inconsistency could arise from the two oscillatory modes in water, which are associated with the bending of hydrogen bonds and intermolecular collisions inside the first coordination shell. The overall results lead us to conclude that the universality of the Frenkel line as a dynamic crossover line from rigid to nonrigid fluids is preserved in water.

Reference intervals for lymphocyte subsets in preterm and term neonates without immune defects.

BACKGROUND: In 6.5 years of newborn screening for severe combined immunodeficiency in California, 3,252,156 infants had DNA from dried blood spots (DBSs) assayed for T-cell receptor excision circles. Infants with T-cell receptor excision circle values of less than a designated cutoff on a single DBS, 2 DBS samples with insufficient PCR amplification, or known genetic risk of immunodeficiency had peripheral blood complete blood counts and lymphocyte subsets assayed in a single flow cytometry laboratory. Cases in which immune defects were ruled out were available for analysis. OBJECTIVE: We sought to determine reference intervals for lymphocyte subsets in racially/ethnically diverse preterm and term newborns who proved to be unaffected by any T-lymphopenic immune disorder. METHODS: Effective gestational age (GA) was defined as GA at birth plus postnatal age at the time of sample collection. After determining exclusion criteria, we analyzed demographic and clinical information, complete and differential white blood cell counts, and lymphocyte subsets for 301 infants, with serial measurements for 33 infants. Lymphocyte subset measurements included total T cells, helper and cytotoxic T-cell subsets, naive and memory phenotype of each T-cell subset, B cells, and natural killer cells. RESULTS: Reference intervals were generated for absolute numbers and lymphocyte subsets from infants with effective GAs of 22 to 52 weeks. Sex and ethnicity were not significant determinants of lymphocyte subset counts in this population. Lymphocyte counts increased postnatally. CONCLUSION: This study provides a baseline for interpreting comprehensive lymphocyte data in preterm and term infants, aiding clinicians to determine which newborns require further evaluations for immunodeficiency.

Electrical conductivity, ion pairing, and ion self-diffusion in aqueous NaCl solutions at elevated temperatures and pressures.

We have performed classical molecular dynamics (MD) simulations of aqueous sodium chloride (NaCl) solutions from 298 to 674 K at 200 bars to understand the influence of ion pairing and ion self-diffusion on electrical conductivity in high-temperature/high-pressure salt solutions. Conductivity data obtained from the MD simulation highlight an apparent anomaly, namely, a conductivity maximum as temperature increases along an isobar, which has been also observed in experimental studies. By examining both velocity autocorrelation and cross-correlation terms of the Green-Kubo integral, we quantitatively demonstrate that the conductivity anomaly arises mainly from a competition between the single-ion self-diffusion and the contact ion pair formation. The velocity autocorrelation function in conjunction with structural analysis suggests that diffusive motion of ions is suppressed at high temperatures due to the persistence of an inner hydration shell. The contribution of velocity cross-correlation functions between oppositely charged ions becomes significant at the onset of the conductivity decrease. Structural analysis based on Voronoi tessellation and pair correlation functions indicates that the fraction of contact ion pairs increases as temperature increases. Spatial decomposition of the electrical conductivity also indicates that the formation of contact ion pairs significantly decreases the electrical conductivity compared to Nernst-Einstein conductivity, but the contribution of distant opposite charges cannot be ignored except at the highest temperature due to unscreened long-range interactions.

Whole exome and whole genome sequencing with dried blood spot DNA without whole genome amplification.

Newborn screening (NBS) for rare conditions is performed in all 50 states in the USA. We have partnered with the California Department of Public Health Genetic Disease Laboratory to determine whether sufficient DNA can be extracted from archived dried blood spots (DBS) for next-generation sequencing in the hopes that next-generation sequencing can play a role in NBS. We optimized the DNA extraction and sequencing library preparation protocols for residual infant DBS archived over 20 years ago and successfully obtained acceptable whole exome and whole genome sequencing data. This sequencing study using DBS DNA without whole genome amplification prior to sequencing library preparation provides evidence that properly stored residual newborn DBS are a satisfactory source of DNA for genetic studies.

Follow-up status during the first 5 years of life for metabolic disorders on the federal Recommended Uniform Screening Panel.

PURPOSE: To investigate the 5-year follow-up status for newborns diagnosed with metabolic disorders designated as "primary disorders" on the federal Recommended Uniform Screening Panel (RUSP). METHODS: Follow-up status and demographic characteristics are described for 426 newborns diagnosed with one of 20 primary metabolic disorders on the RUSP between 2005 and 2009. Newborn screening program data were linked to birth certificate data. Follow-up status is described for each year through age 5 and by disorder type. Maternal characteristics of those who stayed in active care were compared with those who did not. RESULTS: Of 426 diagnosed newborns, by the end of 5 years of follow-up 55.2% stayed in active care, 20.4% became lost to follow-up, 8.7% moved out of state, 6.3% were determined to require no further follow-up, 4.7% refused follow-up, and 4.7% died. Among the initial group of disorders with more than 10 diagnosed cases, phenylketonuria (90%) had the highest percentage of patients still in active care after 5 years. Patients in active care had similar characteristics to patients not in active care when maternal age, race/ethnicity, completed education years, and expected source of payment for delivery were compared. CONCLUSION: Staying in active care may associate with disorder type but not maternal characteristics.

Genomic sequencing in cystic fibrosis newborn screening: what works best, two-tier predefined CFTR mutation panels or second-tier CFTR panel followed by third-tier sequencing?

PurposeThe purpose of this study was to model the performance of several known two-tier, predefined mutation panels and three-tier algorithms for cystic fibrosis (CF) screening utilizing the ethnically diverse California population.MethodsThe cystic fibrosis transmembrane conductance regulator (CFTR) mutations identified among the 317 CF cases in California screened between 12 August 2008 and 18 December 2012 were used to compare the expected CF detection rates for several two- and three-tier screening approaches, including the current California approach, which consists of a population-specific 40-mutation panel followed by third-tier sequencing when indicated.ResultsThe data show that the strategy of using third-tier sequencing improves CF detection following an initial elevated immunoreactive trypsinogen and detection of only one mutation on a second-tier panel.ConclusionIn a diverse population, the use of a second-tier panel followed by third-tier CFTR gene sequencing provides a better detection rate for CF, compared with the use of a second-tier approach alone, and is an effective way to minimize the referrals of CF carriers for sweat testing. Restricting screening to a second-tier testing to predefined mutation panels, even broad ones, results in some missed CF cases and demonstrates the limited utility of this approach in states that have diverse multiethnic populations.

Newborn screening for hyperargininemia due to arginase 1 deficiency.

Hyperargininemia caused by Arginase 1 deficiency is a rare disorder of the urea cycle that can be diagnosed by elevation of arginine in newborn screening blood spots when analyzed by tandem mass spectrometry. Hyperargininemia is currently included as a secondary target on the U.S. Recommended Uniform Screening Panel, which directly influences state-based newborn screening. Because of the apparent low disease frequency and lack of case detection and treatment data, detailed attention has not been given to a model newborn screening algorithm including appropriate analytical cutoff values for disease indicators. In this paper we assess the frequency of hyperargininemia in the U.S. identified by newborn screening to date and document the current status and variability of hyperargininemia newborn screening across U.S. newborn screening programs. We also review other data that support improved screening efficacy by utilizing the arginine/ornithine ratio and other amino acid ratios as discriminators in the screening algorithm. Analysis of archived California screening data showed that an arginine cutoff of 50µM combined with an arginine/ornithine ratio of 1.4 would have resulted in a recall rate of 0.01%. Using an arginine cutoff of 60µM and an arginine/(phenylalanine x leucine) ratio of 1.4, reportedly used in one screening program, or the R4S Tool Runner, would have resulted in a recall rate of <0.005%. All 9 diagnosed patients would have been found for either protocol. Thus, use of appropriate ratios as part of the screening algorithm has the potential to increase both screening sensitivity and specificity. Improved newborn screening effectiveness should lead to better case detection and more rapid treatment to lower plasma arginine levels hence improving long term outcome of individuals with hyperargininemia.

Damaged goods?: an empirical cohort study of blood specimens collected 12 to 23 hours after birth in newborn screening in California.

PURPOSE: The current Clinical and Laboratory Standards Institute standard recommends blood collection from 24 to 48 hours after birth for newborn genetic disorder screening. We used California population-level data to determine whether early specimens (collected from 12 to 23 hours) would also be considered satisfactory based on screening performance. METHODS: Screening data from California Genetic Disease Screening Program were analyzed for false-negative and false-positive rates in four disease categories: metabolic disorders detectable by tandem mass spectrometry (MS/MS); congenital adrenal hyperplasia (CAH); congenital hypothyroidism (CH); and initial immune reactive trypsinogen (IRT) for cystic fibrosis (CF). We compared the rates between the early-collection group (12 to 23 hours) and the standard-collection group (24 to 48 hours). RESULTS: No significant difference of false-negative rate was detected between the two collection-timing groups. Early specimens had a significantly higher false-positive rate for CH (0.10 vs. 0.01%) and IRT (1.85 vs. 1.54%) but a lower false-positive rate for MSMS metabolic disorders (0.11 vs. 0.18%) and CAH (0.10 vs. 0.14%). CONCLUSION: Newborn specimens collected after 12 hours provided satisfactory screening performance. A policy allowing earlier collection could improve timeliness of reporting screening results.

Cell-free DNA vs sequential screening for the detection of fetal chromosomal abnormalities.

BACKGROUND: Sequential and cell-free DNA (cfDNA) screening are both tests for the common aneuploidies. Although cfDNA has a greater detection rate (DR) for trisomy 21, sequential screening also can identify risk for other aneuploidies. The comparative DR for all chromosomal abnormalities is unknown. OBJECTIVE: To compare sequential and cfDNA screening for detection of fetal chromosomal abnormalities in a general prenatal cohort. STUDY DESIGN: The performance of sequential screening for the detection of chromosome abnormalities in a cohort of patients screened through the California Prenatal Screening Program with estimated due dates between August 2009 and December 2012 was compared with the estimated DRs and false-positive rates (FPRs) of cfDNA screening if used as primary screening in this same cohort. DR and FPR for cfDNA screening were abstracted from the published literature, as were the rates of "no results" in euploid and aneuploid cases. Chromosome abnormalities in the entire cohort were categorized as detectable (trisomies 13, 18, and 21, and sex chromosome aneuploidy), or not detectable (other chromosome abnormalities) by cfDNA screening. DR and FPR were compared for individual and all chromosome abnormalities. DR and FPR for the cohort were compared if "no results" cases were considered "screen negative" or "screen positive" for aneuploidy. DR and FPR rates were compared by use of the Fisher exact test. RESULTS: Of 452,901 women who underwent sequential screening during the time period of the study, 2575 (0.57%) had a fetal chromosomal abnormality; 2101 were detected for a DR of 81.6%, and 19,929 euploid fetuses had positive sequential screening for an FPR rate of 4.5%. If no results cases were presumed normal, cfDNA screening would have detected 1820 chromosome abnormalities (70.7%) with an FPR of 0.7%. If no results cases were considered screen positive, 1985 (77.1%) cases would be detected at a total screen positive rate of 3.7%. In either case, the detection rate of sequential screening for all aneuploidies in the cohort was greater than cfDNA (P<.0001). CONCLUSION: For primary population screening, cfDNA provides lower DR than sequential screening if considering detection of all chromosomal abnormalities. Assuming that no results cfDNA cases are high-risk improves cfDNA detection but with a greater FPR. cfDNA should not be adopted as primary screening without further evaluation of the implications for detection of all chromosomal abnormalities and how to best evaluate no results cases.

Racial-ethnic differences in midtrimester maternal serum levels of angiogenic and antiangiogenic factors.

BACKGROUND: Little is known about racial-ethnic differences in the distribution of maternal serum levels of angiogenic and antiangiogenic factors and their associations with early-onset preeclampsia. OBJECTIVE: We sought to investigate the distribution of midtrimester maternal serum levels of placental growth factor, soluble endoglin, and soluble vascular endothelial growth factor receptor 1 and their associations with early-onset preeclampsia in whites, Hispanics, and blacks. STUDY DESIGN: A population-based nested case-control design was used to identify cases and controls of white, Hispanic, and black origin from a 2000 through 2007 live-birth cohort in 5 southern California counties. Cases included 197 women (90 whites, 67 Hispanics, and 40 blacks) with early-onset preeclampsia defined as hypertension and proteinuria with onset <32 weeks according to hospital records. Controls included a random sample of 2363 women without early-onset preeclampsia. Maternal serum specimens collected at 15-20 weeks' gestation as part of routine prenatal screening were tested for placental growth factor, soluble endoglin, and soluble vascular endothelial growth factor receptor 1. Serum levels of the 3 factors were log-normally distributed. Adjusted natural logarithmic means were compared between cases and controls and between racial-ethnic groups. Odds ratios and 95% confidence intervals derived from logistic regression models were calculated to measure the magnitude of the associations. RESULTS: Cases showed lower adjusted logarithmic means of placental growth factor but higher adjusted logarithmic means of soluble endoglin than controls across all 3 groups (P < .05). Cases also had higher adjusted means of soluble vascular endothelial growth factor receptor 1 than controls in whites (7.75 vs 7.52 log pg/mL, P < .05) and Hispanics (7.73 vs 7.40 log pg/mL, P < .05) but not in blacks (7.85 vs 7.69 log pg/mL, P = .47). Blacks were found to have higher levels of placental growth factor in both cases and controls when compared to whites and Hispanics (adjusted means: 4.69 and 5.20 log pg/mL in blacks, 4.08 and 4.78 log pg/mL in whites, and 3.89 and 4.70 log pg/mL in Hispanics, respectively, P < .05). Hispanic cases had the highest adjusted mean of soluble endoglin compared to white and black cases (9.24, 9.05, and 8.93 log pg/mL, respectively, P < .05). The weakest association of early-onset preeclampsia with placental growth factor and soluble endoglin was observed in blacks. The adjusted odds ratio per log pg/mL increase of the 2 analytes were 0.219 (95% confidence interval, 0.124-0.385) and 5.02 (95% confidence interval, 2.56-9.86) in blacks in comparison to 0.048 (95% confidence interval, 0.026-0.088) and 36.87 (95% confidence interval, 17.00-79.96) in whites (P < .05) and 0.028 (95% confidence interval, 0.013-0.060) and 86.68 (95% confidence interval, 31.46-238.81) in Hispanics (P < .05), respectively. As for soluble vascular endothelial growth factor receptor 1, the association was not significantly different among the racial-ethnic groups. CONCLUSION: Racial-ethnic differences were observed in the distribution of midtrimester maternal levels of placental growth factor and soluble endoglin and in the associations with early-onset preeclampsia. These differences should be considered in future studies to improve etiologic and prognostic understanding of early-onset preeclampsia.

Risk of critical congenital heart defects by nuchal translucency norms.

OBJECTIVE: The purpose of this study was to compare the performance of first-trimester nuchal translucency (NT) cutoff of ≥3.5 mm with NT percentiles that were calculated for crown-rump length to identify fetuses with critical congenital heart defects (CCHDs). STUDY DESIGN: This was a population-level study of singleton pregnancies in California with NT measurements performed between 11 and 14 weeks of gestation. Eligible cases were those that resulted in live births from 2009-2010 and had information about the presence or absence of CCHDs available in the hospital discharge records through age 1 year (n = 76,089). Logistic binomial regression methods were used to compare the rate of CCHDs by an NT percentile for crown-rump length and millimeter cutpoints. RESULTS: Compared with fetuses with an NT measurement of <90th percentile, fetuses with an NT of ≥99th percentile were >5 times as likely to have a CCHD (1.3% vs 0.2%; relative risk, 5.66; 95% confidence interval, 3.19-10.04) and fetuses with an NT measurement ≥3.5 mm were >12 times as likely to have a CCHD (2.8% vs 0.2%; relative risk, 12.28; 95% confidence interval, 5.11-29.51). NT ≥99th percentile had a sensitivity of 5.8% and a specificity of 98.9% for the detection of CCHDs compared with 2.6% and 99.8% for NT ≥3.5 mm. CONCLUSION: Results show that NT measurements of ≥99th percentile and ≥3.5 mm are not equivalent and that substantial risk for CCHD extends to the less restrictive ≥99th percentile cutpoint. Data suggest that the use of this cutpoint compared with the current standard could double the number of CCHDs that are identified based on NT risk.

Undiagnosed metabolic dysfunction and sudden infant death syndrome--a case-control study.

BACKGROUND: Decades of research has yielded few clues about causes of sudden infant death syndrome (SIDS). While some studies have shown a link to inborn errors of metabolism (IEMs), few have examined the link in a large population-based sample. This population-based case-control study assessed the association between undiagnosed IEMs and SIDS. METHODS: Children born in California during 2005-08 who died from SIDS were obtained from death records and linked to the newborn screening, birth certificate, and hospital discharge databases. Individuals with known chromosomal and neural tube defects, genetic disorders, and non-singleton births were excluded. Five controls were matched to each case on tandem mass spectrometry testing date and lab code. Rates of undiagnosed IEMs were compared between cases and controls using conditional logistic regression adjusting for known confounding factors. RESULTS: After adjusting for known confounding factors, SIDS cases had similar risk of having IEMs as controls (adjusted hazard ratio [HR] 1.3, 95% confidence interval [CI] 0.3, 5.5). Infants who were male, Black, and born preterm had higher risk of SIDS with the highest risk observed for those born preterm [adjusted HR = 1.7, 95% CI 1.3, 2.2]. Younger maternal age at delivery, mother being born in the US, parity after current birth >3, and delayed prenatal care were also significantly associated with higher risk of SIDS. CONCLUSIONS: While many maternal and infant factors are associated with an increased risk of SIDS, there is no evidence that undiagnosed IEMs are associated with increased risk.

The utility of nuchal translucency ultrasound in identifying rare chromosomal abnormalities not detectable by cell-free DNA screening.

OBJECTIVE: To evaluate the utility of nuchal translucency (NT) screening in the detection of rare chromosomal aneuploidies in the setting of cell-free DNA (cfDNA). METHODS: A retrospective cohort study of pregnancies screened through the California Prenatal Screening Program between March 2009 and December 2012. Karyotype analysis was the primary method of chromosomal evaluation during the study period and abnormal chromosomal karyotype results were classified by whether the abnormality would be detectable by cfDNA (nonmosaic trisomy 13, 18, 21 or sex-chromosomal aneuploidy [SCA]). For those rare aneuploidies detectable by karyotype but not cfDNA, the number of cases that had an increased NT and the detection rate and positive predictive value (PPV) of increased NT for rare aneuploidies were determined. RESULTS: A total of 452 901 pregnant women had screening. There were 2572 chromosomally abnormal fetuses, of which 1922 (74.7%) had a common aneuploidy detectable by cfDNA, leaving 450 979 without T13, 18, 21. Of these, 4181 (0.93%) had an NT ≥3.0 mm. There were 649 rare aneuploidies not detectable by cfDNA. Of these, 108 (16.6%) had an NT ≥3.0 mm. The PPV of an NT ≥3.0 mm for rare aneuploidies was 2.6%. In all, 4176 fetuses need to be screened with NT to detect a rare aneuploidy. CONCLUSIONS: The addition of NT to cfDNA screening would detect 16.6% of rare aneuploidies. Increased NT has a low PPV for rare aneuploidies and a large number of women would need NT screening to detect each affected fetus.

Early-onset severe preeclampsia by first trimester pregnancy-associated plasma protein A and total human chorionic gonadotropin.

OBJECTIVE: This study aims to evaluate the relationship between early-onset severe preeclampsia and first trimester serum levels of pregnancy-associated plasma protein A (PAPP-A) and total human chorionic gonadotropin (hCG). STUDY DESIGN: The association between early-onset severe preeclampsia and abnormal levels of first trimester PAPP-A and total hCG in maternal serum were measured in a sample of singleton pregnancies without chromosomal defects that had integrated prenatal serum screening in 2009 and 2010 (n = 129,488). Logistic binomial regression was used to estimate the relative risk (RR) of early-onset severe preeclampsia in pregnancies with abnormal levels of first trimester PAPP-A or total hCG as compared with controls. RESULTS: Regardless of parity, women with low first trimester PAPP-A or high total hCG were at increased risk for early-onset severe preeclampsia. Women with low PAPP-A (multiple of the median [MoM] ≤ the 10th percentile in nulliparous or ≤ the 5th percentile in multiparous) or high total hCG (MoM ≥ the 90th percentile in nulliparous or ≥ the 95th percentile in multiparous) were at more than a threefold increased risk for early-onset severe preeclampsia (RR, 4.2; 95% confidence interval [CI], 3.0-5.9 and RR, 3.3; 95% CI, 2.1-5.2, respectively). CONCLUSION: Routinely collected first trimester measurements of PAPP-A and total hCG provide unique risk information for early-onset severe preeclampsia.

Postanalytical tools improve performance of newborn screening by tandem mass spectrometry.

PURPOSE: The purpose of this study was to compare performance metrics of postanalytical interpretive tools of the Region 4 Stork collaborative project to the actual outcome based on cutoff values for amino acids and acylcarnitines selected by the California newborn screening program. METHODS: This study was a retrospective review of the outcome of 176,186 subjects born in California between 1 January and 30 June 2012. Raw data were uploaded to the Region 4 Stork Web portal as .csv files to calculate tool scores for 48 conditions simultaneously using a previously unpublished functionality, the tool runner. Scores for individual target conditions were deemed informative when equal or greater to the value representing the first percentile rank of known true-positive cases (17,099 cases in total). RESULTS: In the study period, the actual false-positive rate and positive predictive value were 0.26 and 10%, respectively. Utilization of the Region 4 Stork tools, simple interpretation rules, and second-tier tests could have achieved a false-positive rate as low as 0.02% and a positive predictive value >50% by replacing the cutoff system with Region 4 Stork tools as the primary method for postanalytical interpretation. CONCLUSION: Region 4 Stork interpretive tools, second-tier tests, and other evidence-based interpretation rules could have reduced false-positive cases by up to 90% in California.