PURPOSE: To explore long-term trajectories of children who received rapid genome sequencing (RGS) in intensive care settings. METHODS: We examined the electronic health records (EHR) of 67 critically ill pediatric patients who received RGS six to eight years ago with a collective initial diagnostic yield of 46%. RESULTS: The median length of follow up was 6.2 years (IQR 4.0-7.2 years). RGS-diagnosed patients had a longer average follow-up time compared to undiagnosed patients (5.9 years vs 4.8 years, p = 0.026) and more subspecialty appointments per follow-up year (9.4 vs 6.9, p = 0.036). Mortality during the follow-up period was 9%. Patients averaged 2.1 hospital readmissions per follow-up year and 28.1 hospitalized days per follow-up year. Forty-four patients (66%) had a documented new phenotype in the EHR during their follow-up period. Seven patients received clinician-driven re-analysis during the follow-up period, yielding one new diagnosis. Systematic reanalysis of RGS performed as part of this study identified four new candidate diagnoses. CONCLUSION: Pediatric patients who receive RGS during intensive care unit hospitalizations continue to be high healthcare utilizers in subsequent years, regardless of whether RGS identified a diagnosis. Additionally, two-thirds of this cohort had a documented phenotypic change over the follow-up period, indicating dynamic clinical evolution in the years following RGS.

Identifying critically ill newborns who will benefit from whole genome sequencing (WGS) is difficult and time-consuming due to complex eligibility criteria and evolving clinical features. The Mendelian Phenotype Search Engine (MPSE) automates the prioritization of neonatal intensive care unit (NICU) patients for WGS. Using clinical data from 2885 NICU patients, we evaluated the utility of different machine learning (ML) classifiers, clinical natural language processing (CNLP) tools, and types of Electronic Health Record (EHR) data to identify sick newborns with genetic diseases. Our results show that MPSE can identify children most likely to benefit from WGS within the first 48 h after NICU admission, a critical window for maximally impactful care. Moreover, MPSE provided stable, robust means to identify these children using many combinations of classifiers, CNLP tools, and input data types-meaning MPSE can be used by diverse health systems despite differences in EHR contents and IT support.

The use of genomic sequencing (GS) for prenatal diagnosis of fetuses with sonographic abnormalities has grown tremendously over the past decade. Fetal GS also offers an opportunity to identify incidental genomic variants that are unrelated to the fetal phenotype but may be relevant to fetal and newborn health. There are currently no guidelines for reporting incidental findings from fetal GS. In the United States, GS for adults and children is recommended to include a list of “secondary findings” genes (ACMG SF v.3.2) that are associated with disorders for which surveillance or treatment can reduce morbidity and mortality. The genes on ACMG SF v.3.2 predominantly cause adult-onset disorders. Importantly, many genetic disorders with fetal and infantile onset are treatable as well. A proposed solution is to create a “treatable fetal findings list,” which can be offered to pregnant individuals undergoing fetal GS or, eventually, as a standalone cell-free fetal DNA screening test. In this integrative review, we propose criteria for a treatable fetal findings list, then identify genetic disorders with clinically available or emerging fetal interventions and those for which clinical detection and intervention in the first week of life might lead to improved outcomes. Finally, we synthesize the potential benefits, limitations, and risks of a treatable fetal findings list.

Meningomyelocele (also known as spina bifida) is considered to be a genetically complex disease resulting from a failure of the neural tube to close. Individuals with meningomyelocele display neuromotor disability and frequent hydrocephalus, requiring ventricular shunting. A few genes have been proposed to contribute to disease susceptibility, but beyond that it remains unexplained1. We postulated that de novo mutations under purifying selection contribute to the risk of developing meningomyelocele2. Here we recruited a cohort of 851 meningomyelocele trios who required shunting at birth and 732 control trios, and found that de novo likely gene disruption or damaging missense mutations occurred in approximately 22.3% of subjects, with 28% of such variants estimated to contribute to disease risk. The 187 genes with damaging de novo mutations collectively define networks including actin cytoskeleton and microtubule-based processes, Netrin-1 signalling and chromatin-modifying enzymes. Gene validation demonstrated partial or complete loss of function, impaired signalling and defective closure of the neural tube in Xenopus embryos. Our results indicate that de novo mutations make key contributions to meningomyelocele risk, and highlight critical pathways required for neural tube closure in human embryogenesis.

Human GABAergic inhibitory neurons (INs) in the telencephalon play crucial roles in modulating neural circuits, generating cortical oscillations, and maintaining the balance between excitation and inhibition. The major IN subtypes are based on their gene expression profiles, morphological diversity and circuit-specific functions. Although previous foundational work has established that INs originate in the ganglionic eminence regions in mice, recent studies have questioned origins in humans and non-human primates. We review the origins of INs in mice and compare with recent findings from primary human prenatal brain tissue culture experiments and lineage analysis from somatic variants in neurotypical human cadavers and human brain organoids. Together, these studies suggest potential primate- or human-specific processes that may have been overlooked in mouse models and could have implications for brain disorders.

Meningomyelocele (MM) is considered a genetically complex disease resulting from failure of neural tube closure (NTD). Patients display neuromotor disability and frequent hydrocephalus requiring ventricular shunting. A few proposed genes contribute to disease susceptibility, but most risk remains unexplained. We postulated that de novo mutations (DNMs) under purifying selection contribute to MM risk. Here we recruited a cohort of 851 MM trios requiring shunting at birth, compared with 732 control trios, and found that de novo likely gene disrupting or damaging missense mutations occur in approximately 22.3% of subjects, 28% of which are estimated to contribute to disease risk. The 187 genes with damaging DNMs collectively define networks including actin cytoskeleton and microtubule-based processes, axon guidance, and histone modification. Gene validation demonstrates partial or complete loss of function, impaired signaling and defective neural tube closure in Xenopus embryos. Our results suggest DNMs make key contributions to MM risk, and highlight critical pathways required for neural tube closure in human embryogenesis.

In this issue of Neuron, Yang et al.1 reveal that primary cilia in mouse prefrontal cortex excitatory neurons regulate stress responses via cAMP/PKA signaling. Stress induces ciliary elongation, enhancing corticosterone-mediated neuronal inhibition. Cilia loss reduces stress sensitivity, highlighting their role in stress adaptation, with potential therapeutic relevance.

The Mendelian Phenotype Search Engine (MPSE), a clinical decision support tool using Natural Language Processing and Machine Learning, helped neonatologists expedite decisions to whole genome sequencing (WGS) to diagnose patients in the neonatal intensive care unit. After the MPSE was introduced, utilization of WGS increased, time to ordering WGS decreased, and WGS diagnostic yield increased.

Large prospective clinical trials are underway or planned that examine the clinical utility and cost effectiveness of genome-based newborn screening (gNBS). One gNBS platform, BeginNGS, currently screens 53,575 variants for 412 severe childhood genetic diseases with 1,603 efficacious therapies. Retrospective evaluation of BeginNGS in 618,290 subjects suggests adequate sensitivity and positive predictive value (PPV) to proceed to prospective studies. To inform pivotal clinical trial design, we undertook a pilot clinical trial. We enrolled 120 infants in a regional neonatal intensive care unit (NICU) who were not under consideration for rapid diagnostic genome sequencing (RDGS). Each enrollee received BeginNGS and two index tests (California state NBS and RDGS). California NBS identified 4 of 4 true positive (TP) findings (TP rate 3.6%, sensitivity 100%) and 11 false positive (FP) findings (PPV 27%). RDGS identified 41 diagnostic findings in 36 neonates (diagnostic rate 30%). BeginNGS identified 5 of 6 on-target TP disorders (TP rate 4.2%, 95% confidence interval 1%-8%, sensitivity 83%) and no FPs (PPV 100%). Changes in management were anticipated following the return of 27 RDGS results in 25 enrollees (clinical utility [CU] 21%), 3 of 4 NBS TPs (CU 2.7%), and all BeginNGS TPs (CU 4.2%). The incidence of actionable genetic diseases in NICU infants not being considered for RDGS suggests (1) performance of RDGS in ∼20% of admissions misses many genetic diagnoses, (2) NICU enrollment in gNBS trials will greatly increase power to test endpoints, and (3) NICUs may be attractive for early implementation of consented BeginNGS screening.

Genome-sequence-based newborn screening (gNBS) has substantial potential to improve outcomes in hundreds of severe childhood genetic disorders (SCGDs). However, a major impediment to gNBS is imprecision due to variants classified as pathogenic (P) or likely pathogenic (LP) that are not SCGD causal. gNBS with 53,855 P/LP variants, 342 genes, 412 SCGDs, and 1,603 therapies was positive in 74% of UK Biobank (UKB470K) adults, suggesting 97% false positives. We used the phenomenon of purifying hyperselection, which acts to decrease the frequency of SCGD causal diplotypes, to reduce false positives. Training of gene-disease-inheritance mode-diplotype tetrads in 618,290 control and affected subjects identified 293 variants or haplotypes and seven genes with variable inheritance contributing higher positive diplotype counts than consistent with purifying hyperselection and with little or no evidence of SCGD causality. With these changes, 2.0% of UKB470K adults were positive. In contrast, gNBS was positive in 7.2% of 3,118 critically ill children with suspected SCGDs and 7.9% of 705 infant deaths. When compared with rapid diagnostic genome sequencing (RDGS), gNBS had 99.1% recall. In eight true-positive children, gNBS was projected to decrease time to diagnosis by a median of 121 days and avoid life-threatening disease presentations in four children, organ damage in six children, ∼$1.25 million in healthcare cost, and ten (1.4%) infant deaths. Federated training predicated on purifying hyperselection provides a general framework to attain high precision in population screening. Federated training across many biobanks and clinical trials can provide a privacy-preserving mechanism for qualification of gNBS in diverse genetic ancestries.