Rare earth elements are a group of seventeen chemically similar metals, including neodymium, cerium, and ytterbium, that have become indispensable to modern technology. They appear in magnets, batteries, catalysts, and electronic displays, and as mining and manufacturing have intensified worldwide, these elements have quietly accumulated in soil, water, and air. People are exposed through food, drinking water, and dust, and pregnant women pass them across the placenta to their developing babies. While previous research had hinted that prenatal exposure to these metals could impair childhood neurodevelopment, the biological mechanisms remained murky.

To probe those mechanisms, researchers turned to the Wuhan Healthy Baby Cohort, a long-running birth cohort study in central China. The team, led by Ya Xie and Wei Xia of Wuhan Children’s Hospital and Huazhong University of Science and Technology, measured concentrations of thirteen rare earth elements in urine samples collected from mothers during the first trimester of pregnancy. They then performed metabolomic profiling on cord blood, the blood remaining in the placenta after birth, capturing a snapshot of each newborn’s metabolic state. Two years later, trained assessors evaluated each child’s cognitive and motor skills using the Bayley Scales of Infant Development, a widely used standardized test.

The results were striking. After adjusting for a range of covariates, the researchers found that higher first-trimester maternal levels of seven rare earth elements were each significantly associated with increased odds of cognitive developmental delay. The elements neodymium, samarium, gadolinium, holmium, erbium, thulium, and ytterbium each carried elevated risk, with adjusted odds ratios ranging from 1.13 to 1.25 for every one-unit increase in natural log-transformed urinary concentration. In practical terms, a modest rise in maternal exposure translated into a measurable increase in the likelihood that a toddler would score below developmental benchmarks on cognitive testing.

Because people are exposed to mixtures of rare earth elements rather than single metals in isolation, the team also used two statistical approaches designed for environmental mixtures: quantile g-computation and weighted quantile sum regression. Both methods confirmed a positive overall mixture effect, meaning the combined burden of rare earth elements raised the risk of both cognitive and psychomotor developmental delays. Intriguingly, the two methods identified different dominant contributors. Ytterbium emerged as the primary driver of cognitive developmental delay, while cerium played the leading role in psychomotor delay, hinting that individual rare earth elements may exert distinct biological effects even within a chemically similar family.

The study’s most innovative move came next. Rather than treating metabolites as isolated signals, the researchers applied weighted gene co-expression network analysis, a technique originally developed for genomics, to the cord blood metabolomic data. Using a soft-thresholding power of 5, which produced a network with strong scale-free topology, the team clustered thousands of metabolites into thirteen color-coded modules representing coordinated metabolic networks. This approach allowed them to ask which entire biological pathways, rather than individual molecules, were perturbed by prenatal rare earth exposure.

Two modules stood out. Prenatal rare earth element exposure was consistently associated with perturbations in metabolic modules enriched in lysophospholipids and phosphatidylethanolamines, two classes of phospholipids that are fundamental building blocks of cell membranes. These molecules are especially important in the developing brain, where membranes are being rapidly assembled and remodeled as neurons grow and form connections. The finding suggests that rare earth elements may interfere with fetal neurodevelopment by scrambling the lipid architecture on which brain construction depends.

Crucially, the association was more than correlational. Mediation analyses demonstrated that the lysophospholipid and phosphatidylethanolamine modules partially mediated the link between prenatal exposure and increased risk of neurodevelopmental delay. In other words, part of the statistical pathway from rare earth exposure to developmental impairment runs through these disrupted lipid networks. The identification of a plausible biological mechanism elevates the findings from an observational association toward a more causal interpretation, though the researchers note that mediation captures only a portion of the overall effect and other pathways likely remain to be discovered.

The implications ripple outward in several directions. For public health officials, the study strengthens the case for including rare earth elements in routine risk assessments during pregnancy, a step that has lagged far behind their growing environmental presence. As global demand for these metals surges with the green energy transition and the proliferation of electronic devices, exposure levels in ordinary populations may continue to climb. The study also points toward potential interventions: if phospholipid disruption is a key mechanism, researchers could eventually explore whether nutritional or pharmacological strategies that support healthy lipid metabolism during pregnancy might buffer developing brains against environmental insult.

For the families in Wuhan whose participation made the study possible, the research offers no easy answers, since rare earth exposure is diffuse and difficult for individuals to avoid. But it adds an urgent data point to a larger conversation about the hidden costs of the technologies that define modern life. The metals that power our digital world are now demonstrably reaching the next generation before they take their first breath, and the developing brain appears to register their presence in ways we are only beginning to measure. As the authors conclude, the findings highlight the need for health risk assessment of rare earth element exposure during pregnancy, and they provide early clues to intervention targets that could protect children before the damage is done.

Subject of Research: Prenatal rare earth element exposure and its association with neurodevelopmental delay and phospholipid metabolic disruption in children

Article Title: Cord blood metabolic network profiles link prenatal rare earth element exposure to neurodevelopmental delay in 2-year-old children

Article References: Xie, Y., Qiu, L., Fang, X., Cao, Z., Li, S., Gong, H., Tan, T., Wang, J., Li, Y., Xu, S., Xiao, H., Zhou, A., & Xia, W. (2026). Cord blood metabolic network profiles link prenatal rare earth element exposure to neurodevelopmental delay in 2-year-old children. BMC Medicine. https://doi.org/10.1186/s12916-026-05306-9

Image Credits: AI Generated

DOI: 10.1186/s12916-026-05306-9

Keywords: rare earth elements, prenatal exposure, neurodevelopmental delay, metabolomics, cord blood, phospholipid metabolism, WGCNA, Bayley Scales, birth cohort, cognitive development, psychomotor development, environmental health

The study, published in BMC Infectious Diseases, analyzed clinical records from infants admitted to the hospital’s neonatal intensive care unit between May 2023 and February 2025. All of the patients were preterm, and the median age at which sepsis first appeared was just sixteen days, though the range stretched remarkably wide, from seven days to 223 days after birth. That timing matters. Late-onset sepsis, meaning infection that develops after the first seventy-two hours of life, is a leading cause of illness and death in preterm infants, and the usual suspects are well-known organisms such as coagulase-negative staphylococci. Bacillus cereus rarely tops the list of clinical suspicions, and that is precisely the problem the researchers set out to illuminate.

The clinical picture that emerged from the nineteen cases was strikingly non-specific, which helps explain why the organism is so easy to overlook. Every single infant, one hundred percent of the cohort, presented with poor responsiveness, a vague sign that overlaps with countless other conditions in fragile newborns. Fever was present in fourteen patients, or 73.9 percent, and apnea, the temporary cessation of breathing, occurred in twelve infants, accounting for 63.2 percent. None of these findings would immediately point a clinician toward Bacillus cereus. In fact, the study’s authors note that positive blood cultures for this organism are frequently dismissed as contamination, since Bacillus species are common environmental organisms that can inadvertently seed a culture bottle during sampling. Distinguishing true invasive infection from a stray contaminant requires clinical judgment, and the stakes of getting that call wrong are now considerably clearer.

One of the most consequential findings of the study concerned breathing. Among the sixteen infants who had not been receiving invasive mechanical ventilation before the onset of sepsis, ten, or 62.5 percent, required escalation to a higher level of respiratory support once the infection took hold. The researchers report this figure with a 95 percent confidence interval of 35.4 percent to 84.8 percent, a wide range that reflects the modest sample size but still signals a consistent pattern. In practical terms, a sudden deterioration in respiratory status in a preterm infant, manifesting as new or worsening apnea and increased oxygen requirements, may be one of the earliest and most reliable signals that sepsis is developing. For neonatal clinicians, the message is that a step up in respiratory support should trigger a careful search for infection, including blood cultures, rather than being attributed to the infant’s underlying prematurity alone.

The microbiology added its own sobering lessons. Every strain isolated in the cohort was resistant to penicillin and ampicillin, the beta-lactam antibiotics that form the backbone of empiric therapy for many neonatal infections. This resistance is a hallmark of Bacillus cereus, which produces beta-lactamase enzymes that dismantle penicillin-class drugs. The good news is that all strains remained susceptible to meropenem, vancomycin, and linezolid, giving clinicians effective options once the organism is identified. But the resistance pattern underscores a diagnostic trap: if Bacillus cereus is not considered and the infant is treated with ampicillin alone, the infection may continue to progress even as treatment appears to be under way. Timely identification of the organism and rational adjustment of the antimicrobial regimen are therefore not optional refinements but essential steps in managing these patients.

The most alarming dimension of the study concerns the central nervous system. Two of the nineteen infants, or 10.5 percent, developed purulent meningitis, the bacterial infection of the membranes surrounding the brain, and one of those cases progressed to a brain abscess, a localized collection of pus within brain tissue itself. The researchers provided a detailed account of this abscess case and then cast a wider net, searching the published literature for other reported cases of neonatal Bacillus cereus brain abscess. Combining their own patient with the literature yielded fifteen cases in total. Among those fifteen infants, five deaths were reported, a mortality rate of 33.3 percent. And the toll did not end with survival: some of the children who lived were left with neurological sequelae, lasting damage to brain function that can shape development for a lifetime.

The outcome of the Quanzhou abscess case illustrates both the gravity of the complication and the possibility of rescue through aggressive intervention. The infant survived after undergoing surgical drainage of the abscess combined with long-term antimicrobial therapy, a regimen that must be sustained for weeks to eradicate bacteria sequestered within an abscess cavity, where antibiotic penetration is poor and the blood-brain barrier complicates drug delivery. Yet survival came with a caveat. At twenty months of age, the child exhibited mild neuromotor developmental delay, a reminder that even successfully treated central nervous system infection in a preterm infant can leave subtle but meaningful traces on the developing brain. The developing nervous system of a premature infant is uniquely vulnerable, and inflammatory injury during critical windows of brain maturation can disrupt processes that unfold over months and years.

Overall mortality in the cohort was 5.3 percent, meaning one of the nineteen infants died, with a 95 percent confidence interval of 0.1 percent to 26.0 percent. That figure, while far lower than the mortality seen in the brain abscess literature, still represents a death toll from an organism that many clinicians would regard as a nuisance contaminant. The authors argue that their findings justify a more proactive diagnostic pathway. In their view, any preterm infant with a positive blood culture for Bacillus cereus should undergo lumbar puncture to examine the cerebrospinal fluid and cranial imaging as soon as possible, rather than waiting for neurological signs to appear. By the time seizures, bulging fontanelles, or other overt signs of central nervous system involvement emerge, an abscess may already be forming. Serial neuroimaging and long-term neurodevelopmental follow-up round out the recommended approach, ensuring that survivors are monitored for delays that may only become apparent as they grow.

Where does the bacterium come from in the first place? The study points to potential sources that are uncomfortably close to the infant’s bedside: contaminated environmental surfaces, medical equipment, and nutritional products, including breast milk and formula. Bacillus cereus is a spore-forming organism, and its spores are notoriously resistant to heat, drying, and disinfectants, allowing it to persist on surfaces and in equipment long after cleaning. This resilience is what makes the bacterium such a formidable opportunist in hospital settings. The authors emphasize that prevention rests on disciplined fundamentals: strict hand hygiene among staff and caregivers, regular and thorough disinfection of the environment and medical devices, and careful handling of breast milk and formula to prevent bacterial growth. These measures are neither glamorous nor technologically novel, but they target the routes by which spores travel from the environment into the bloodstream of an infant whose immune defenses are still under construction.

The significance of this study lies less in any single statistic than in the cumulative picture it paints. Bacillus cereus sepsis in preterm infants is rare enough that most evidence has previously been limited to isolated case reports or small series, leaving clinicians without a clear sense of the typical presentation, the likely course, or the full range of complications. By assembling nineteen cases from a single center and pairing them with a systematic review of the brain abscess literature, the Quanzhou team has transformed a scattered collection of anecdotes into a coherent clinical profile: a non-specific onset marked by poor responsiveness, fever, apnea, and escalating respiratory support; universal beta-lactam resistance demanding prompt antimicrobial adjustment; and a real, quantifiable risk of meningitis and brain abscess with lasting developmental consequences. For the neonatologists and infection-control teams who staff the world’s intensive care nurseries, the study is a call to take this soil-dwelling organism seriously, to investigate positive cultures rather than dismissing them, and to look beyond the bloodstream toward the brain before it is too late.

Subject of Research: Invasive Bacillus cereus sepsis and neurological complications in hospitalized preterm infants

Article Title: Invasive Bacillus cereus infection in hospitalized preterm infants: clinical characteristics, outcomes, and neurological complications from a single-center retrospective case series

Article References: Xue’e, Z., Zhiyong, L., Xialin, Y., Jiangbin, C., Jingyang, Z., Tianfeng, C., Ruiquan, W., Lianqiang, W., Weifeng, Z., Jinglin, X., Dongmei, C., & Hongyuan, Y. (2026). Invasive Bacillus cereus infection in hospitalized preterm infants: clinical characteristics, outcomes, and neurological complications from a single-center retrospective case series. BMC Infectious Diseases. https://doi.org/10.1186/s12879-026-14504-y

Image Credits: AI Generated

DOI: 10.1186/s12879-026-14504-y

Keywords: Bacillus cereus, preterm infants, neonatal sepsis, brain abscess, meningitis, neonatal intensive care, antimicrobial resistance, meropenem, vancomycin, neurodevelopmental delay, healthcare-associated infection, infection control

To appreciate why this matters, it helps to understand what EED actually does. The gene encodes a core subunit of the Polycomb Repressive Complex 2, or PRC2, one of the most important epigenetic machines in human cells. Alongside its partners EZH2, SUZ12, and the retinoblastoma binding proteins RBBP4 and RBBP7, EED helps silence genes by recognizing and propagating a chemical mark on histones, the protein spools around which DNA is wound. Specifically, the complex deposits and maintains tri-methylation of histone H3 at lysine 27, a modification that compacts chromatin and shuts down transcription. EED plays the crucial role of reading this mark and extending it along the chromosome, a mechanism essential for regulating developmental genes and preserving cellular identity. When one copy of EED is disabled, the fine-tuning of gene expression during growth and brain development goes awry, producing the overgrowth syndromes that have fascinated geneticists for the past decade.

The clinical family of PRC2-related overgrowth disorders is small but distinctive. Heterozygous germline variants in EZH2 cause Weaver syndrome, marked by tall stature, macrocephaly, advanced bone age, and characteristic facial features. Variants in EED produce Cohen–Gibson syndrome, while alterations in SUZ12 underlie Imagawa–Matsumoto syndrome. All three overlap substantially with one another and with Sotos syndrome, featuring prenatal and postnatal overgrowth, hypotonia, and intellectual disability of variable severity. The facial gestalt of EED-related cases can usually be distinguished from Weaver syndrome, particularly in older children, by features such as telecanthus, narrow palpebral fissures, ptosis, downslanted upper eyelids, and eversion of the lower lateral eyelid margins. Some individuals also present with congenital heart defects, genitourinary anomalies, structural brain abnormalities, and epilepsy, reflecting the variable expressivity of these epigenetic disorders.

The girl at the center of the new report was born at 36 weeks and three days of gestation by cesarean section, prompted by maternal edema and hypertension. From the very first moments of life, the signs of overgrowth were unmistakable: she weighed 4500 grams, more than three and three-quarter standard deviations above the mean, measured 55 centimeters in length, and had a head circumference of 38 centimeters. Postnatal hypotonia was noted immediately. Developmental milestones arrived late, with unsupported walking at around 24 months and first words at about 30 months. Today she attends a school for children with intellectual disabilities and receives a broad program of physiotherapy, occupational therapy, and speech therapy. At age 12, her height measured 173.5 centimeters, nearly three standard deviations above average, and facial examination revealed hypertelorism, narrow palpebral fissures, periorbital fullness, and large, posteriorly rotated ears, alongside genu valgum, thin calves, and slender fingers with short first and fifth metacarpals.

Notably, her bone age at 10 years and 4 months matched her chronological age, but projected adult height, calculated by the Bayley and Pinneau method, reached an estimated 192 centimeters, dramatically exceeding the mid-parental target height of 163 centimeters. Endocrinological workup was unremarkable, chromosomal analysis showed a normal 46,XX karyotype, and the family history across three generations was entirely uneventful, with no other affected individuals. Intriguingly, two artificial intelligence tools designed to recognize rare disease from facial photographs, GestaltMatcher and Face2Gene, both flagged Cohen–Gibson syndrome among their top suggestions, with Face2Gene assigning it to the ultra-rare category at 76 percent gestalt similarity. That computational nudge helped steer the diagnostic team toward the right corner of the genome.

Whole-exome sequencing of blood-derived DNA then delivered the decisive clue: a missense variant in exon 10 of EED, designated c.1091G>T, which substitutes leucine for the conserved tryptophan at position 364 of the protein. Crucially, the variant was present at a variant allele fraction of only about 28 percent, far below the 50 percent expected for a heterozygous germline change. Targeted deep sequencing confirmed a fraction of 31 percent in blood, 30 percent in saliva, and between 11 and 17 percent in two independently collected buccal mucosa samples. Neither parent carried the variant above the assay’s validated detection threshold of roughly 1 percent, and the trace reads observed in their samples were consistent with sequencing artifacts. The tissue distribution, spanning both mesoderm-derived blood and ectoderm-derived buccal mucosa, pointed to a postzygotic mutation arising early in embryogenesis, after fertilization but before the embryo’s cells had fully committed to their developmental fates.

The molecular properties of the variant strengthen the case for its pathogenicity. The altered tryptophan sits within the WD40 repeat domain of EED and forms part of the aromatic cage that binds trimethylated H3K27, the very interaction that allosterically activates PRC2 and allows the complex to propagate its repressive marks. A single nucleotide change at this residue is extraordinarily rare: population databases record it exactly once among nearly 1.6 million alleles, and it appears in neither ClinVar nor the Human Gene Mutation Database. A battery of computational predictors, including AlphaMissense, CADD, PolyPhen, REVEL, PhyloP, PrimateAI-3D, and SIFT, uniformly predicted a deleterious effect. Under American College of Medical Genetics and Genomics guidelines, the variant was classified as likely pathogenic on the strength of its confirmed de novo status, its extreme rarity, the computational evidence, and the highly specific match between the patient’s phenotype and known EED-related disease.

Perhaps the most elegant piece of evidence came not from DNA sequencing at all but from the epigenome. Genome-wide DNA methylation profiling on the Illumina EPIC BeadChip platform, analyzed with the EpiSign METRIC software, revealed a methylation pattern that matched the established episignature of PRC2 complex disorders, which encompasses both EED-associated syndrome and EZH2-associated Weaver syndrome. In hierarchical clustering heatmaps, multidimensional scaling plots, and t-distributed stochastic neighbor embedding visualizations, the patient’s sample clustered tightly with the PRC2 reference cohort and separated cleanly from controls. In other words, the mutation is not merely present; it is functionally active, leaving a measurable genome-wide fingerprint of dysregulated gene silencing. This convergence of sequencing, structural biology, and epigenetic profiling illustrates how modern molecular diagnostics can triangulate a diagnosis from multiple independent lines of evidence.

The discovery also reshapes thinking about mosaicism in overgrowth syndromes more broadly. Postzygotic mosaicism is a well-established mechanism in disorders driven by somatic activating variants in genes such as PIK3CA and AKT1, which cause conditions like CLOVES syndrome and Proteus syndrome. But for PRC2-related overgrowth, mosaicism had never been observed, and variant databases list only germline alterations. The new case shows that intermediate-level mosaicism, with variant allele fractions between 11 and 31 percent across tissues, is sufficient to produce a multisystemic phenotype of moderate severity, including cardiac valvular insufficiency, musculoskeletal anomalies, and increased patellar reflexes. It also carries a practical lesson: had the diagnostic workup relied on blood alone, or on a single tissue, the variant might have been missed or its significance underestimated. Multi-tissue sequencing, the authors argue, should be considered whenever clinical suspicion remains high despite negative or ambiguous initial testing.

Limitations remain, as the researchers themselves acknowledge. This is a single-case observation, and no functional assays were performed to directly demonstrate how the variant perturbs PRC2 activity in cells. Whether the degree of mosaicism correlates with phenotypic severity is still an open question, and systematic studies in larger cohorts will be needed to establish standardized approaches for assessing the clinical relevance of mosaic PRC2 variants. Nevertheless, the message for clinicians is clear: mosaicism deserves a routine place in the differential diagnosis of PRC2-related syndromes, particularly in patients with unexplained or atypical overgrowth and developmental delay. For the families of children who have endured years of inconclusive genetic testing, the recognition that a postzygotic mutation can masquerade as, or produce, Cohen–Gibson syndrome offers a new and potentially decisive avenue toward the answer they have been searching for.

Subject of Research: Mosaic EED variant causing Cohen–Gibson syndrome, a PRC2-related overgrowth and neurodevelopmental disorder

Article Title: Mosaicism for Cohen–Gibson Syndrome in a Female Individual With Overgrowth and Neurodevelopmental Delay

Article References: Song, F., Michels, M., Betz, B., Vorhoff, W., Neuhann, T., Senninger, L., & Wieczorek, D. (2026). Mosaicism for Cohen–Gibson Syndrome in a Female Individual With Overgrowth and Neurodevelopmental Delay. Molecular Genetics & Genomic Medicine, 14(10), Article e70286. https://doi.org/10.1002/mgg3.70286

Image Credits: AI Generated

DOI: 10.1002/mgg3.70286

Keywords: Cohen-Gibson syndrome, EED, PRC2, mosaicism, overgrowth syndrome, Weaver syndrome, epigenetics, DNA methylation, episignature, whole-exome sequencing, neurodevelopmental delay, rare disease