Novel variants in TECRL leading to catecholaminergic polymorphic ventricular tachycardia.

Pathogenic and likely pathogenic variants in the TECRL gene are known to be associated with recessive catecholaminergic polymorphic ventricular tachycardia 3, which can include prolonged QT intervals (MIM#614021). We report a case of cardiac arrest in a previously healthy adolescent male in the community. The patient was found to have a novel maternally inherited likely pathogenic variant in TECRL (c.915T>G [p.Tyr305Ter]) and an additional 19-kb duplication encompassing multiple exons of TECRL (chr4:65165944-65185287, dup [4q13.1]) not identified in the mother. Genetic results were revealed via rapid whole-genome sequencing, which allowed appropriate treatment and prognostication.

Cell-type-resolved mosaicism reveals clonal dynamics of the human forebrain.

Debate remains around the anatomical origins of specific brain cell subtypes and lineage relationships within the human forebrain1-7. Thus, direct observation in the mature human brain is critical for a complete understanding of its structural organization and cellular origins. Here we utilize brain mosaic variation within specific cell types as distinct indicators for clonal dynamics, denoted as cell-type-specific mosaic variant barcode analysis. From four hemispheres and two different human neurotypical donors, we identified 287 and 780 mosaic variants, respectively, that were used to deconvolve clonal dynamics. Clonal spread and allele fractions within the brain reveal that local hippocampal excitatory neurons are more lineage-restricted than resident neocortical excitatory neurons or resident basal ganglia GABAergic inhibitory neurons. Furthermore, simultaneous genome transcriptome analysis at both a cell-type-specific and a single-cell level suggests a dorsal neocortical origin for a subgroup of DLX1+ inhibitory neurons that disperse radially from an origin shared with excitatory neurons. Finally, the distribution of mosaic variants across 17 locations within one parietal lobe reveals that restriction of clonal spread in the anterior-posterior axis precedes restriction in the dorsal-ventral axis for both excitatory and inhibitory neurons. Thus, cell-type-resolved somatic mosaicism can uncover lineage relationships governing the development of the human forebrain.

Rapid Whole-Genome Sequencing and Clinical Management in the PICU: A Multicenter Cohort, 2016-2023.

OBJECTIVES: Analysis of the clinical utility of rapid whole-genome sequencing (rWGS) outside of the neonatal period is lacking. We describe the use of rWGS in PICU and cardiovascular ICU (CICU) patients across four institutions. DESIGN: Ambidirectional multisite cohort study. SETTING: Four tertiary children's hospitals. PATIENTS: Children 0-18 years old in the PICU or CICU who underwent rWGS analysis, from May 2016 to June 2023. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: A total of 133 patients underwent clinical, phenotype-driven rWGS analysis, 36 prospectively. A molecular diagnosis was identified in 79 patients (59%). Median (interquartile range [IQR]) age was 6 months (IQR 1.2 mo-4.6 yr). Median time for return of preliminary results was 3 days (IQR 2-4). In 79 patients with a molecular diagnosis, there was a change in ICU management in 19 patients (24%); and some change in clinical management in 63 patients (80%). Nondiagnosis changed management in 5 of 54 patients (9%). The clinical specialty ordering rWGS did not affect diagnostic rate. Factors associated with greater odds ratio (OR [95% CI]; OR [95% CI]) of diagnosis included dysmorphic features (OR 10.9 [95% CI, 1.8-105]) and congenital heart disease (OR 4.2 [95% CI, 1.3-16.8]). Variables associated with greater odds of changes in management included obtaining a genetic diagnosis (OR 16.6 [95% CI, 5.5-62]) and a shorter time to genetic result (OR 0.8 [95% CI, 0.76-0.9]). Surveys of pediatric intensivists indicated that rWGS-enhanced clinical prognostication (p < 0.0001) and contributed to a decision to consult palliative care (p < 0.02). CONCLUSIONS: In this 2016-2023 multiple-PICU/CICU cohort, we have shown that timely genetic diagnosis is feasible across institutions. Application of rWGS had a 59% (95% CI, 51-67%) rate of diagnostic yield and was associated with changes in critical care management and long-term patient management.

Multi-center implementation of rapid whole genome sequencing provides additional evidence of its utility in the pediatric inpatient setting.

Objective: Multi-center implementation of rapid whole genome sequencing with assessment of the clinical utility of rapid whole genome sequencing (rWGS), including positive, negative and uncertain results, in admitted infants with a suspected genetic disease. Study design: rWGS tests were ordered at eight hospitals between November 2017 and April 2020. Investigators completed a survey of demographic data, Human Phenotype Ontology (HPO) terms, test results and impacts of results on clinical care. Results: A total of 188 patients, on general hospital floors and intensive care unit (ICU) settings, underwent rWGS testing. Racial and ethnic characteristics of the tested infants were broadly representative of births in the country at large. 35% of infants received a diagnostic result in a median of 6 days. The most common HPO terms for tested infants indicated an abnormality of the nervous system, followed by the cardiovascular system, the digestive system, the respiratory system and the head and neck. Providers indicated a major change in clinical management because of rWGS for 32% of infants tested overall and 70% of those with a diagnostic result. Also, 7% of infants with a negative rWGS result and 23% with a variant of unknown significance (VUS) had a major change in management due to testing. Conclusions: Our study demonstrates that the implementation of rWGS is feasible across diverse institutions, and provides additional evidence to support the clinical utility of rWGS in a demographically representative sample of admitted infants and includes assessment of the clinical impact of uncertain rWGS results in addition to both positive and negative results.

Rapid genomic sequencing for genetic disease diagnosis and therapy in intensive care units: a review.

Single locus (Mendelian) diseases are a leading cause of childhood hospitalization, intensive care unit (ICU) admission, mortality, and healthcare cost. Rapid genome sequencing (RGS), ultra-rapid genome sequencing (URGS), and rapid exome sequencing (RES) are diagnostic tests for genetic diseases for ICU patients. In 44 studies of children in ICUs with diseases of unknown etiology, 37% received a genetic diagnosis, 26% had consequent changes in management, and net healthcare costs were reduced by $14,265 per child tested by URGS, RGS, or RES. URGS outperformed RGS and RES with faster time to diagnosis, and higher rate of diagnosis and clinical utility. Diagnostic and clinical outcomes will improve as methods evolve, costs decrease, and testing is implemented within precision medicine delivery systems attuned to ICU needs. URGS, RGS, and RES are currently performed in <5% of the ~200,000 children likely to benefit annually due to lack of payor coverage, inadequate reimbursement, hospital policies, hospitalist unfamiliarity, under-recognition of possible genetic diseases, and current formatting as tests rather than as a rapid precision medicine delivery system. The gap between actual and optimal outcomes in children in ICUs is currently increasing since expanded use of URGS, RGS, and RES lags growth in those likely to benefit through new therapies. There is sufficient evidence to conclude that URGS, RGS, or RES should be considered in all children with diseases of uncertain etiology at ICU admission. Minimally, diagnostic URGS, RGS, or RES should be ordered early during admissions of critically ill infants and children with suspected genetic diseases.

The Plasma Lipidomic Landscape in Patients with Sepsis due to Community-acquired Pneumonia.

Rationale: The plasma lipidome has the potential to reflect many facets of the host status during severe infection. Previous work is limited to specific lipid groups or was focused on lipids as prognosticators.Objectives: To map the plasma lipidome during sepsis due to community-acquired pneumonia (CAP) and determine the disease specificity and associations with clinical features.Methods: We analyzed 1,833 lipid species across 33 classes in 169 patients admitted to the ICU with sepsis due to CAP, 51 noninfected ICU patients, and 48 outpatient controls. In a paired analysis, we reanalyzed patients still in the ICU 4 days after admission (n = 82).Measurements and Main Results: A total of 58% of plasma lipids were significantly lower in patients with CAP-attributable sepsis compared with outpatient controls (6% higher, 36% not different). We found strong lipid class-specific associations with disease severity, validated across two external cohorts, and inflammatory biomarkers, in which triacylglycerols, cholesterol esters, and lysophospholipids exhibited the strongest associations. A total of 36% of lipids increased over time, and stratification by survival revealed diverging lipid recovery, which was confirmed in an external cohort; specifically, a 10% increase in cholesterol ester levels was related to a lower odds ratio (0.84; P = 0.006) for 30-day mortality (absolute mortality, 18 of 82). Comparison with noninfected ICU patients delineated a substantial common illness response (57.5%) and a distinct lipidomic signal for patients with CAP-attributable sepsis (37%).Conclusions: Patients with sepsis due to CAP exhibit a time-dependent and partially disease-specific shift in their plasma lipidome that correlates with disease severity and systemic inflammation and is associated with higher mortality.

Genome sequencing detects a wide range of clinically relevant copy-number variants and other genomic alterations.

PURPOSE: Copy-number variants (CNVs) and other non-single nucleotide variant/indel variant types contribute an important proportion of diagnoses in individuals with suspected genetic disease. This study describes the range of such variants detected by genome sequencing (GS). METHODS: For a pediatric cohort of 1032 participants undergoing clinical GS, we characterize the CNVs and other non-single nucleotide variant/indel variant types that were reported, including aneuploidies, mobile element insertions, and uniparental disomies, and we describe the bioinformatic pipeline used to detect these variants. RESULTS: Together, these genetic alterations accounted for 15.8% of reported variants. Notably, 67.9% of these were deletions, 32.9% of which overlapped a single gene, and many deletions were reported together with a second variant in the same gene in cases of recessive disease. A retrospective medical record review in a subset of this cohort revealed that up to 6 additional genetic tests were ordered in 68% (26/38) of cases, some of which failed to report the CNVs/rare variants reported on GS. CONCLUSION: GS detected a broad range of reported variant types, including CNVs ranging in size from 1 Kb to 46 Mb.

NBSTRN Tools to Advance Newborn Screening Research and Support Newborn Screening Stakeholders.

Rapid advances in the screening, diagnosis, and treatment of genetic disorders have increased the number of conditions that can be detected through universal newborn screening (NBS). However, the addition of conditions to the Recommended Uniform Screening Panel (RUSP) and the implementation of nationwide screening has been a slow process taking several years to accomplish for individual conditions. Here, we describe web-based tools and resources developed and implemented by the newborn screening translational research network (NBSTRN) to advance newborn screening research and support NBS stakeholders worldwide. The NBSTRN's tools include the Longitudinal Pediatric Data Resource (LPDR), the NBS Condition Resource (NBS-CR), the NBS Virtual Repository (NBS-VR), and the Ethical, Legal, and Social Issues (ELSI) Advantage. Research programs, including the Inborn Errors of Metabolism Information System (IBEM-IS), BabySeq, EarlyCheck, and Family Narratives Use Cases, have utilized NBSTRN's tools and, in turn, contributed research data to further expand and refine these resources. Additionally, we discuss ongoing tool development to facilitate the expansion of genetic disease screening in increasingly diverse populations. In conclusion, NBSTRN's tools and resources provide a trusted platform to enable NBS stakeholders to advance NBS research and improve clinical care for patients and their families.

Rapid Whole-Genomic Sequencing and a Targeted Neonatal Gene Panel in Infants With a Suspected Genetic Disorder.

Importance: Genomic testing in infancy guides medical decisions and can improve health outcomes. However, it is unclear whether genomic sequencing or a targeted neonatal gene-sequencing test provides comparable molecular diagnostic yields and times to return of results. Objective: To compare outcomes of genomic sequencing with those of a targeted neonatal gene-sequencing test. Design, Setting, and Participants: The Genomic Medicine for Ill Neonates and Infants (GEMINI) study was a prospective, comparative, multicenter study of 400 hospitalized infants younger than 1 year of age (proband) and their parents, when available, suspected of having a genetic disorder. The study was conducted at 6 US hospitals from June 2019 to November 2021. Exposure: Enrolled participants underwent simultaneous testing with genomic sequencing and a targeted neonatal gene-sequencing test. Each laboratory performed an independent interpretation of variants guided by knowledge of the patient's phenotype and returned results to the clinical care team. Change in clinical management, therapies offered, and redirection of care was provided to families based on genetic findings from either platform. Main Outcomes and Measures: Primary end points were molecular diagnostic yield (participants with ≥1 pathogenic variant or variant of unknown significance), time to return of results, and clinical utility (changes in patient care). Results: A molecular diagnostic variant was identified in 51% of participants (n = 204; 297 variants identified with 134 being novel). Molecular diagnostic yield of genomic sequencing was 49% (95% CI, 44%-54%) vs 27% (95% CI, 23%-32%) with the targeted gene-sequencing test. Genomic sequencing did not report 19 variants found by the targeted neonatal gene-sequencing test; the targeted gene-sequencing test did not report 164 variants identified by genomic sequencing as diagnostic. Variants unidentified by the targeted genomic-sequencing test included structural variants longer than 1 kilobase (25.1%) and genes excluded from the test (24.6%) (McNemar odds ratio, 8.6 [95% CI, 5.4-14.7]). Variant interpretation by laboratories differed by 43%. Median time to return of results was 6.1 days for genomic sequencing and 4.2 days for the targeted genomic-sequencing test; for urgent cases (n = 107) the time was 3.3 days for genomic sequencing and 4.0 days for the targeted gene-sequencing test. Changes in clinical care affected 19% of participants, and 76% of clinicians viewed genomic testing as useful or very useful in clinical decision-making, irrespective of a diagnosis. Conclusions and Relevance: The molecular diagnostic yield for genomic sequencing was higher than a targeted neonatal gene-sequencing test, but the time to return of routine results was slower. Interlaboratory variant interpretation contributes to differences in molecular diagnostic yield and may have important consequences for clinical management.

Assessing Diversity in Newborn Genomic Sequencing Research Recruitment: Race/Ethnicity and Primary Spoken Language Variation in Eligibility, Enrollment, and Reasons for Declining.

PURPOSE: Diagnostic genomic research has the potential to directly benefit participants. This study sought to identify barriers to equitable enrollment of acutely ill newborns into a diagnostic genomic sequencing research study. METHODS: We reviewed the 16-month recruitment process of a diagnostic genomic research study enrolling newborns admitted to the neonatal intensive care unit at a regional pediatric hospital that primarily serves English- and Spanish-speaking families. Differences in eligibility, enrollment, and reasons for not enrolling were examined as functions of race/ethnicity and primary spoken language. FINDINGS: Of the 1248 newborns admitted to the neonatal intensive care unit, 46% (n = 580) were eligible, and 17% (n = 213) were enrolled. Of the 16 languages represented among the newborns' families, 4 (25%) had translated consent documents. Speaking a language other than English or Spanish increased a newborn's likelihood of being ineligible by 5.9 times (P < 0.001) after controlling for race/ethnicity. The main reason for ineligibility was documented as the clinical team declined having their patient recruited (41% [51 of 125]). This reason significantly affected families who spoke languages other than English or Spanish and was able to be remediated with training of the research staff. Stress (20% [18 of 90]) and the study intervention(s) (20% [18 of 90]) were the main reasons given for not enrolling. IMPLICATIONS: This analysis of eligibility, enrollment, and reasons for not enrolling in a diagnostic genomic research study found that recruitment generally did not differ as a function of a newborn's race/ethnicity. However, differences were observed depending on the parent's primary spoken language. Regular monitoring and training can improve equitable enrollment into diagnostic genomic research. There are also opportunities at the federal level to improve access to those with limited English proficiency and thus decrease disparities in representation in research participation.

Rapid Whole Genome Sequencing for Diagnosis of Single Locus Genetic Diseases in Critically Ill Children.

Upon admission to intensive care units (ICU), the differential diagnosis of almost all infants with diseases of unclear etiology includes single locus genetic diseases. Rapid whole genome sequencing (rWGS), including sample preparation, short-read sequencing-by-synthesis, informatics pipelining, and semiautomated interpretation, can now identify nucleotide and structural variants associated with most genetic diseases with robust analytic and diagnostic performance in as little as 13.5 h. Early diagnosis of genetic diseases transforms medical and surgical management of infants in ICUs, minimizing both the duration of empiric treatment and the delay to start of specific treatment. Both positive and negative rWGS tests have clinical utility and can improve outcomes. Since first described 10 years ago, rWGS has evolved considerably. Here we describe our current methods for routine diagnostic testing for genetic diseases by rWGS in as little as 18 h.

3D genome mapping identifies subgroup-specific chromosome conformations and tumor-dependency genes in ependymoma.

Ependymoma is a tumor of the brain or spinal cord. The two most common and aggressive molecular groups of ependymoma are the supratentorial ZFTA-fusion associated and the posterior fossa ependymoma group A. In both groups, tumors occur mainly in young children and frequently recur after treatment. Although molecular mechanisms underlying these diseases have recently been uncovered, they remain difficult to target and innovative therapeutic approaches are urgently needed. Here, we use genome-wide chromosome conformation capture (Hi-C), complemented with CTCF and H3K27ac ChIP-seq, as well as gene expression and DNA methylation analysis in primary and relapsed ependymoma tumors, to identify chromosomal conformations and regulatory mechanisms associated with aberrant gene expression. In particular, we observe the formation of new topologically associating domains ('neo-TADs') caused by structural variants, group-specific 3D chromatin loops, and the replacement of CTCF insulators by DNA hyper-methylation. Through inhibition experiments, we validate that genes implicated by these 3D genome conformations are essential for the survival of patient-derived ependymoma models in a group-specific manner. Thus, this study extends our ability to reveal tumor-dependency genes by 3D genome conformations even in tumors that lack targetable genetic alterations.

Isolated Absent Aortic Valves: A Unique Fetal Case With Echocardiographic, Pathologic, and Genetic Correlation.

We present a 22-week fetus with isolated absent aortic valve and inverse circular shunt. The pregnancy was interrupted. Here, echocardiography and pathology images demonstrate this rare entity. Whole genome sequencing revealed a potentially disease-causing variant in the APC gene. Whole genome sequencing should be considered in severe and rare fetal diseases. (Level of Difficulty: Advanced.).

Genomic sequencing has a high diagnostic yield in children with congenital anomalies of the heart and urinary system.

Background: Congenital heart defects (CHD) and congenital anomalies of the kidney and urinary tract (CAKUT) account for significant morbidity and mortality in childhood. Dozens of monogenic causes of anomalies in each organ system have been identified. However, even though 30% of CHD patients also have a CAKUT and both organs arise from the lateral mesoderm, there is sparse overlap of the genes implicated in the congenital anomalies for these organ systems. We sought to determine whether patients with both CAKUT and CHD have a monogenic etiology, with the long-term goal of guiding future diagnostic work up and improving outcomes. Methods: Retrospective review of electronic medical records (EMR), identifying patients admitted to Rady Children's Hospital between January 2015 and July 2020 with both CAKUT and CHD who underwent either whole exome sequencing (WES) or whole genome sequencing (WGS). Data collected included demographics, presenting phenotype, genetic results, and mother's pregnancy history. WGS data was reanalyzed with a specific focus on the CAKUT and CHD phenotype. Genetic results were reviewed to identify causative, candidate, and novel genes for the CAKUT and CHD phenotype. Associated additional structural malformations were identified and categorized. Results: Thirty-two patients were identified. Eight patients had causative variants for the CAKUT/CHD phenotype, three patients had candidate variants, and three patients had potential novel variants. Five patients had variants in genes not associated with the CAKUT/CHD phenotype, and 13 patients had no variant identified. Of these, eight patients were identified as having possible alternative causes for their CHD/CAKUT phenotype. Eighty-eight percent of all CAKUT/CHD patients had at least one additional organ system with a structural malformation. Conclusions: Overall, our study demonstrated a high rate of monogenic etiologies in hospitalized patients with both CHD and CAKUT, with a diagnostic rate of 44%. Thus, physicians should have a high suspicion for genetic disease in this population. Together, these data provide valuable information on how to approach acutely ill patients with CAKUT and CHD, including guiding diagnostic work up for associated phenotypes, as well as novel insights into the genetics of CAKUT and CHD overlap syndromes in hospitalized children.

Automated prioritization of sick newborns for whole genome sequencing using clinical natural language processing and machine learning.

BACKGROUND: Rapidly and efficiently identifying critically ill infants for whole genome sequencing (WGS) is a costly and challenging task currently performed by scarce, highly trained experts and is a major bottleneck for application of WGS in the NICU. There is a dire need for automated means to prioritize patients for WGS. METHODS: Institutional databases of electronic health records (EHRs) are logical starting points for identifying patients with undiagnosed Mendelian diseases. We have developed automated means to prioritize patients for rapid and whole genome sequencing (rWGS and WGS) directly from clinical notes. Our approach combines a clinical natural language processing (CNLP) workflow with a machine learning-based prioritization tool named Mendelian Phenotype Search Engine (MPSE). RESULTS: MPSE accurately and robustly identified NICU patients selected for WGS by clinical experts from Rady Children's Hospital in San Diego (AUC 0.86) and the University of Utah (AUC 0.85). In addition to effectively identifying patients for WGS, MPSE scores also strongly prioritize diagnostic cases over non-diagnostic cases, with projected diagnostic yields exceeding 50% throughout the first and second quartiles of score-ranked patients. CONCLUSIONS: Our results indicate that an automated pipeline for selecting acutely ill infants in neonatal intensive care units (NICU) for WGS can meet or exceed diagnostic yields obtained through current selection procedures, which require time-consuming manual review of clinical notes and histories by specialized personnel.

Scalable, high quality, whole genome sequencing from archived, newborn, dried blood spots.

Universal newborn screening (NBS) is a highly successful public health intervention. Archived dried bloodspots (DBS) collected for NBS represent a rich resource for population genomic studies. To fully harness this resource in such studies, DBS must yield high-quality genomic DNA (gDNA) for whole genome sequencing (WGS). In this pilot study, we hypothesized that gDNA of sufficient quality and quantity for WGS could be extracted from archived DBS up to 20 years old without PCR (Polymerase Chain Reaction) amplification. We describe simple methods for gDNA extraction and WGS library preparation from several types of DBS. We tested these methods in DBS from 25 individuals who had previously undergone diagnostic, clinical WGS and 29 randomly selected DBS cards collected for NBS from the California State Biobank. While gDNA from DBS had significantly less yield than from EDTA blood from the same individuals, it was of sufficient quality and quantity for WGS without PCR. All samples DBS yielded WGS that met quality control metrics for high-confidence variant calling. Twenty-eight variants of various types that had been reported clinically in 19 samples were recapitulated in WGS from DBS. There were no significant effects of age or paper type on WGS quality. Archived DBS appear to be a suitable sample type for WGS in population genomic studies.

Reclassification of the Etiology of Infant Mortality With Whole-Genome Sequencing.

Importance: Understanding the causes of infant mortality shapes public health, surveillance, and research investments. However, the association of single-locus (mendelian) genetic diseases with infant mortality is poorly understood. Objective: To determine the association of genetic diseases with infant mortality. Design, Setting, and Participants: This cohort study was conducted at a large pediatric hospital system in San Diego County (California) and included 546 infants (112 infant deaths [20.5%] and 434 infants [79.5%] with acute illness who survived; age, 0 to 1 year) who underwent diagnostic whole-genome sequencing (WGS) between January 2015 and December 2020. Data analysis was conducted between 2015 and 2022. Exposure: Infants underwent WGS either premortem or postmortem with semiautomated phenotyping and diagnostic interpretation. Main Outcomes and Measures: Proportion of infant deaths associated with single-locus genetic diseases. Results: Among 112 infant deaths (54 girls [48.2%]; 8 [7.1%] African American or Black, 1 [0.9%] American Indian or Alaska Native, 8 [7.1%] Asian, 48 [42.9%] Hispanic, 1 [0.9%] Native Hawaiian or Pacific Islander, and 34 [30.4%] White infants) in San Diego County between 2015 and 2020, single-locus genetic diseases were the most common identifiable cause of infant mortality, with 47 genetic diseases identified in 46 infants (41%). Thirty-nine (83%) of these diseases had been previously reported to be associated with childhood mortality. Twenty-eight death certificates (62%) for 45 of the 46 infants did not mention a genetic etiology. Treatments that can improve outcomes were available for 14 (30%) of the genetic diseases. In 5 of 7 infants in whom genetic diseases were identified postmortem, death might have been avoided had rapid, diagnostic WGS been performed at time of symptom onset or regional intensive care unit admission. Conclusions and Relevance: In this cohort study of 112 infant deaths, the association of genetic diseases with infant mortality was higher than previously recognized. Strategies to increase neonatal diagnosis of genetic diseases and immediately implement treatment may decrease infant mortality. Additional study is required to explore the generalizability of these findings and measure reduction in infant mortality.

Insights into the perinatal phenotype of Kabuki syndrome in infants identified by genome-wide sequencing.

Increasing use of unbiased genomic sequencing in critically ill infants can expand understanding of rare diseases such as Kabuki syndrome (KS). Infants diagnosed with KS through genome-wide sequencing performed during the initial hospitalization underwent retrospective review of medical records. Human phenotype ontology terms used in genomic analysis were aggregated and analyzed. Clinicians were surveyed regarding changes in management and other care changes. Fifteen infants met inclusion criteria. KS was not suspected prior to genomic sequencing. Variants were classified as Pathogenic (n = 10) or Likely Pathogenic (n = 5) by American College of Medical Genetics and Genomics Guidelines. Fourteen variants were de novo (KMT2D, n = 12, KDM6A, n = 2). One infant inherited a likely pathogenic variant in KMT2D from an affected father. Frequent findings involved cardiovascular (14/15) and renal (7/15) systems, with palatal defects also identified (6/15). Three infants had non-immune hydrops. No minor anomalies were universally documented; ear anomalies, micrognathia, redundant nuchal skin, and hypoplastic nails were common. Changes in management were reported in 14 infants. Early use of unbiased genome-wide sequencing enabled a molecular diagnosis prior to clinical recognition including infants with atypical or rarely reported features of KS while also expanding the phenotypic spectrum of this rare disorder.