Vinod K. Misra

LRP1 encodes the low‐density lipoprotein (LDL) receptor‐related protein 1 (LRP1), a transmembrane protein involved in endocytosis and activation of multiple signaling pathways. LRP1 variants have been implicated in the pathogenesis of congenital heart defects (CHD), Alzheimer's disease, and neurodevelopmental disorders (NDD). Biallelic LRP1 variants have also been reported in two siblings with CHD, hypotonia, dysmorphology, corneal clouding, and ascites. However, conclusive evidence supporting the role of LRP1 in human disease is still lacking. Individuals with heterozygous variants in LRP1 (NM_002332.3) were identified through genetic testing. GeneMatcher facilitated identification of participants and international collaboration. Comprehensive clinical and genotypic data were collected. Fifteen participants with heterozygous predicted loss‐of‐function (pLOF) or missense variants in LRP1 were identified. The most common phenotypes include NDD, CHD, musculoskeletal and gastrointestinal issues, and dysmorphic features. CHD was more common in participants with pLOF variants. Our findings suggest that LRP1 haploinsufficiency is associated with a syndromic NDD. Phenotypic differences in cardiac and neurologic involvement between participants with pLOF and missense variants suggest the possibility of alternate disease mechanisms.

Background/Objectives: Large-for-gestational-age (LGA) birth is associated with adverse perinatal outcomes and increased risk of metabolic disease later in life. Despite these risks, epigenetic studies of LGA remain limited, particularly those using umbilical cord blood DNA methylation (DNAm) as the tissue of interest. Methods: We conducted an epigenome-wide association study of cord blood DNAm in a nested case–control sample from the Gestational Regulators of Weight (GROW) cohort. The analysis included 28 term LGA infants and 63 term appropriate-for-gestational-age (AGA) controls. DNAm was measured using the Illumina HumanMethylation450 BeadChip. Epigenome-wide association analyses were performed with adjustment for residual principal components and estimated cord blood cell-type proportions. Results: No CpG sites reached statistical significance after false discovery rate correction. Twenty-four CpGs showed nominal associations with LGA status at p-value < 1.00 × 10⁻⁴, including five CpGs with absolute methylation differences greater than 0.05. Among annotated loci, the strongest interpretable signals included cg06750897 in PBX1 (Δβ = 0.110, p-value = 1.70 × 10⁻⁵) and two nearby CpGs in SMAD3, cg23731272 (Δβ = 0.111, p-value = 4.31 × 10⁻⁵) and cg02486855 (Δβ = 0.109, p-value = 9.45 × 10⁻⁵). These two SMAD3 CpGs showed concordant hypermethylation in LGA infants and formed a candidate regional methylation signal in exploratory targeted regional analysis. Conclusions: In this pilot study, LGA was associated with modest cord blood DNAm differences, although no CpG sites reached genome-wide significance. The strongest interpretable signals involved PBX1 and SMAD3, suggesting candidate loci for further evaluation in larger studies of fetal overgrowth.

Pathogenic variants in MPDZ are typically associated with congenital hydrocephalus. We report on siblings who present with more complex central nervous system malformations and defects in cardiovascular, ocular, and respiratory systems. Phenotyping of the proband revealed aortic coarctation, bicuspid aortic valve, partial anomalous pulmonary venous return, ventricular septal defect, Dandy-Walker malformation, along with subependymal gray matter heterotopia, megalocornea, and chorioretinal punctate lesions. Prenatal phenotyping of the proband's now deceased brother noted left-sided diaphragmatic hernia, a single cardiac ventricle of right ventricular morphology, aortic and mitral valve hypoplasia with aortic coarctation, ventriculomegaly, and mega cisterna magna. Whole genome sequencing identified a homozygous likely pathogenic canonical splice site variant in MPDZ , c.2650-1G>A in both siblings. These siblings present with features suggesting that MPDZ pathogenicity may be associated with a more complex syndromic neurodevelopmental phenotype with both central nervous system and non–central nervous system features. We speculate that MPDZ influences common morphogenetic pathways underlying these relationships.

Pre-mRNA splicing is a highly coordinated process. While its dysregulation has been linked to neurological deficits, our understanding of the underlying molecular and cellular mechanisms remains limited. We implicated pathogenic variants in U2AF2 and PRPF19, encoding spliceosome subunits in neurodevelopmental disorders (NDDs), by identifying 46 unrelated individuals with 23 de novo U2AF2 missense variants (including 7 recurrent variants in 30 individuals) and 6 individuals with de novo PRPF19 variants. Eight U2AF2 variants dysregulated splicing of a model substrate. Neuritogenesis was reduced in human neurons differentiated from human pluripotent stem cells carrying two U2AF2 hyper-recurrent variants. Neural loss of function (LoF) of the Drosophila orthologs U2af50 and Prp19 led to lethality, abnormal mushroom body (MB) patterning, and social deficits, which were differentially rescued by wild-type and mutant U2AF2 or PRPF19. Transcriptome profiling revealed splicing substrates or effectors (including Rbfox1, a third splicing factor), which rescued MB defects in U2af50-deficient flies. Upon reanalysis of negative clinical exomes followed by data sharing, we further identified 6 patients with NDD who carried RBFOX1 missense variants which, by in vitro testing, showed LoF. Our study implicates 3 splicing factors as NDD-causative genes and establishes a genetic network with hierarchy underlying human brain development and function.

The integration of precision medicine in the care of hospitalized children is ever evolving. However, access to new genomic diagnostics such as rapid whole genome sequencing (rWGS) is hindered by barriers in implementation. Michigan’s Project Baby Deer (PBD) is a multi-center collaborative effort that sought to break down barriers to access by offering rWGS to critically ill neonatal and pediatric inpatients in Michigan. The clinical champion team used a standardized approach with inclusion and exclusion criteria, shared learning, and quality improvement evaluation of the project’s impact on the clinical outcomes and economics of inpatient rWGS. Hospitals, including those without on-site geneticists or genetic counselors, noted positive clinical impacts, accelerating time to definitive treatment for project patients. Between 95–214 hospital days were avoided, net savings of $4155 per patient, and family experience of care was improved. The project spurred policy advancement when Michigan became the first state in the United States to have a Medicaid policy with carve-out payment to hospitals for rWGS testing. This state project demonstrates how front-line clinician champions can directly improve access to new technology for pediatric patients and serves as a roadmap for expanding clinical implementation of evidence-based precision medicine technologies.

Preterm delivery (PTD) may be characterized by altered interrelationships among angiogenic factors and measures of placental function. We analyzed the longitudinal relationship between maternal serum concentrations of soluble fms-like tyrosine kinase 1 (sFlt1), an important antiangiogenic factor, and uterine artery resistance in pregnancies resulting in preterm and term deliveries. Data were collected in a longitudinal cohort study involving 278 women monitored at 6 to 10, 10 to 14, 16 to 20, 22 to 26, and 32 to 36 weeks of gestation. Concentrations of maternal serum sFlt1 were determined using solid-phase enzyme-linked immunosorbent assay, and uterine artery resistance indices (RI) were measured by Doppler velocimetry at each interval. Preterm delivery was defined as birth before 37-weeks completed gestation. Data analyses used multivariable repeated measures regression models. Uterine artery RI decreased across gestation. As pregnancy progressed, RI trajectories diverged for term and preterm deliveries; the mean RI was significantly higher in third trimester for pregnancies resulting in PTD (P = .08). sFlt1 was stable through 21 3/7 weeks of gestation and then increased rapidly; women who delivered preterm had significantly higher sFlt1 levels in the third trimester (P = .04). The relationship between uterine artery RI and sFlt1 from the prior visit was significantly different between the groups (P < .0001). For term deliveries, higher sFlt1 concentrations were associated with a smaller RI at the subsequent visit (β = −.08, 95% confidence interval [CI]: −0.14 to −0.02). For PTD, higher sFlt1 concentrations were associated with a larger uterine artery RI (β = .14, 95% CI: 0.06 to 0.22). PTD is characterized by altered relationships between angiogenic factors and placental vascular blood flow starting in early pregnancy.

X-linked adrenoleukodystrophy (XALD) typically presents as a childhood cerebral demyelinating form, as an adult-onset adrenomyeloneuropathy or as adrenocortical insufficiency. Cerebral demyelination presenting in adolescence is unusual. We present an 17-year-old boy with adolescent-onset XALD initially manifesting with slowly progressive psychiatric symptoms. He was initially diagnosed with attention-deficit hyperactivity disorder and an acute psychosis. However, he was ultimately diagnosed with XALD based on his clinical course, neuroimaging findings and biochemical abnormalities. This case reiterates the atypical presentations of adolescent-onset cerebral XALD that may go unrecognised and misdiagnosed as a neurodevelopmental or psychiatric disease. Treatments for cerebral ALD are potentially life-saving, particularly when given early in the disease course.