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A One Health approach to Antimicrobial Resistance: Concepts, challenges, and advances in omics.

Antimicrobial resistance (AMR) is a global threat driven by the interplay between microbial evolution and human activity. Antimicrobial use in human and veterinary medicine, as well as in agriculture, accelerates the selection and dissemination of resistant bacteria and genes across interconnected human, animal, and environmental reservoirs. These dynamic exchanges render single-sector interventions ineffective. A One Health approach integrating human, animal, and environmental health is therefore essential to understand and mitigate the emergence and spread of AMR. This chapter focuses on bacterial antimicrobial resistance, addressing key concepts, major challenges, and emerging technologies within a One Health framework. Advances in next-generation sequencing and omics technologies have transformed our capacity to resolve AMR at unprecedented scale and resolution. These tools enable the tracking of resistance genes and high-risk clones across ecosystems, uncover transmission pathways, and identify key drivers of dissemination. Such insights support real-time epidemiological surveillance, outbreak detection, and targeted interventions. However, translating these advances into routine practice remains a major challenge, requiring harmonized methodologies, data integration, and cross-sector coordination. Addressing AMR demands sustained collaboration across disciplines and stakeholders, including clinicians, veterinarians, farmers, researchers, policymakers, industry, and the public. And framing AMR as a shared ecological and societal responsibility underscores the urgency of coordinated global action. We call for the urgent integration of One Health principles into surveillance, policy, and innovation to preserve antimicrobial effectiveness and safeguard future health.

Humans↗

Measuring double-strand break repair events in mammalian cells with multi-target CRISPR.

A mechanistic understanding of the different pathways involved in the repair of DSBs is a timely, yet challenging task. CRISPR-Cas9 is a powerful tool to induce DNA double-strand breaks (DSB) at defined genomic locations to study the ensuing repair response, but Cas9 studies are typically limited by i) low-throughput induction of DSB, by targeting only one or a few genomic sites, or ii) the use of genetically integrated reporter systems, which do not always reflect endogenous phenotypes. To address these limitations, we developed multi-target CRISPR, a Cas9-based tool to controllably induce DSBs in high-throughput at endogenous sites, by leveraging repetitive genomic regions. In this Chapter, we describe how to design and execute a multi-target CRISPR experiment. We also detail how to analyze next-generation sequencing data for characterization of DSB repair events at multiple cut sites. We envision that multi-target CRISPR will become a valuable tool for the study of mammalian DSB repair mechanisms.

DNA Breaks, Double-Stranded↗

A quick guide to evaluating prime editing efficiency in mammalian cells.

According to the Clinvar database, modeling the diseases associated with pathogenic mutations requires the installation of base substitutions, small insertions or deletions. Prime editor (PE) was recently developed to precisely install any base substitutions and/or small insertions/deletions (indels) in mammalian cells and animals without requiring DSBs or donor DNA templates. PE also offers greater editing and targeting flexibility compared to other precision CRISPR editing methods because the versatile editing information is encoded in the reverse-transcription template of its prime editing guide RNA. However, optimal PE system selection and experimental design can be complex, and there are various factors that can affect PE efficiency. This chapter serves as a rapid entry-level guideline for the application of PE, providing an experimental framework for using PE at a specific genomic locus. RUNX1 was selected as a representative target site to illustrate the detailed methodology for constructing PE plasmids and the process of transfecting these plasmids into 293FT cells. We further examined the efficiency of PE-mediated genome editing in mammalian cells by using next-generation sequencing.

Gene Editing↗

Polygenic risk score for early identification of coronary artery disease in a real-world clinical setting within the Latvian patient population.

STUDY OBJECTIVE: Polygenic risk scores (PRS) are increasingly recognized for their potential to improve coronary artery disease (CAD) prediction beyond traditional clinical models. This study evaluated the utility of genome-wide association study (GWAS) - derived PRS and pathway-specific PRS (PS-PRS) in the Latvian population, aiming to assess their association with CAD and compare their predictive performance with conventional risk factors. DESIGN PARTICIPANTS AND MAIN OUTCOME MEASURES: The study included 90 early-onset CAD patients and 43 controls with no evidence of atherosclerotic lesions on coronary angiography, with next-generation sequencing performed. PRS was calculated using 192 single nucleotide variants identified from the CARDIoGRAMplusC4D GWAS meta-analysis. The predictive accuracy of PRS, PS-PRS, clinical risk factors, and their combinations was analyzed via ROC curves. RESULTS: The average age was 48.7&#xa0;years in CAD patients and 49.8 in controls. CAD patients showed significantly higher PRS (mean 0.31) compared to controls (mean&#xa0;-&#xa0;0.65; p&#xa0;<&#xa0;0.0001). PRS alone had moderate discriminatory power (AUC&#xa0;=&#xa0;0.773), slightly lower than LDL cholesterol (AUC&#xa0;=&#xa0;0.775) and total cholesterol (AUC&#xa0;=&#xa0;0.821). Combining clinical risk factors improved prediction (AUC&#xa0;=&#xa0;0.872), with the highest accuracy when PRS was integrated with all clinical factors (AUC&#xa0;=&#xa0;0.933). The PRS distributions were significantly elevated in early-onset CAD patients across the angiogenesis/tissue repair pathway (p&#xa0;=&#xa0;0.00038), inflammation pathway (p&#xa0;=&#xa0;0.043), vascular remodelling pathway (p&#xa0;=&#xa0;0.0116), and pathway of genes with unknown function in atherosclerosis (p&#xa0;=&#xa0;0.0035), but overall PRS demonstrated superior discrimination compared to pathway-specific PRS. CONCLUSIONS: Incorporating PRS enhances early-onset CAD risk prediction. Pathway specific PRS had lower discriminative ability than the overall PRS.

Atherosclerosis↗

Barcoded oligonucleotide system (BOLT) for targeted organ delivery.

The therapeutic potential of oligonucleotides (oligos) is limited by insufficient delivery to extrahepatic tissues. In vitro assays often fail to accurately predict in vivo behavior, while testing each oligo candidate in animals remains inherently low throughput. Here, we conceive a barcoded oligonucleotide system (BOLT), a platform that enables high-throughput in vivo evaluations of small-molecule ligands and identifies tissue-specific oligo delivery. BOLT integrates rational design of oligo barcodes, modular conjugation chemistry, and next-generation sequencing (NGS)-based quantification, allowing simultaneous evaluation of many chemically diverse ligand-oligo conjugates within a single animal. Notably, this platform is applicable in both mice and nonhuman primates (NHPs). Using BOLT, we discovered ligands with tropism for tissues such as the brain, lung, and muscle. Collectively, these results indicate that the BOLT platform can accelerate the discovery of tissue-targeting ligands for broad oligo therapeutics.

Journal Article↗

Molecular and immune profiling of HER2-low, HER2 ultra-low, and HER2-null male breast cancer.

BACKGROUND: HER2 expression is described along a biological continuum from null to positive and serves as a critical biomarker for therapeutic guidance in breast cancer (BC). While HER2-low and ultra-low categories have emerged as actionable targets for antibody-drug conjugates (ADCs) in female BC, their molecular and immune characteristics remain largely unexplored in male breast cancer. METHODS: We profiled 214 male breast tumors using next-generation sequencing and whole-transcriptome sequencing to assess mutational, transcriptomic, and immune landscapes. Tumor mutational burden (TMB) was defined as high if&#x202f;>&#x202f;10 mutations/Mb. Immune cell fractions were inferred using Quantiseq deconvolution. RESULTS: Among 214 samples, 66 (30.8%) were HER2-null, 53 (24.8%) HER2 ultra-low, 80 (37.4%) HER2-low, and 15 (7.0%) HER2-positive. HER2 ultra-low tumors exhibited a higher prevalence of PIK3CA mutations (39.2% vs 22.6%, p&#x202f;&#x2264;&#x202f;0.05) compared to HER2-null. No significant differences were observed in TMB-high frequency or PD-L1 expression across subgroups. Immune composition differed primarily between HER2-null and HER2-expressing subgroups: HER2-ultra-low tumors showed higher B-cell infiltration, whereas HER2-null tumors were enriched in neutrophils. Transcriptomic analysis revealed upregulation of selected stemness-associated genes (NANOG, KLF4, POU5F1) and CEACAM1 in HER2-null tumors, while HER2-low and HER2-ultra-low tumors were largely similar across most molecular and immune readouts in this cohort. CONCLUSIONS: HER2-null male breast cancer appears to represent the most biologically divergent subgroup within the HER2-negative spectrum, whereas HER2-low and HER2-ultra-low tumors were largely similar in this cohort. These findings support further investigation of HER2-null disease as a distinct biological state and provide hypothesis-generating data for biomarker development in this rare population.

Male↗

Identification of transcriptome SNPs between Xiphophorus lines and species for assessing allele specific gene expression within F&#x2081; interspecies hybrids.

Variations in gene expression are essential for the evolution of novel phenotypes and for speciation. Studying allelic specific gene expression (ASGE) within interspecies hybrids provides a unique opportunity to reveal underlying mechanisms of genetic variation. Using Xiphophorus interspecies hybrid fishes and high-throughput next generation sequencing technology, we were able to assess variations between two closely related vertebrate species, Xiphophorus maculatus and Xiphophorus couchianus, and their F(1) interspecies hybrids. We constructed transcriptome-wide SNP polymorphism sets between two highly inbred X. maculatus lines (JP 163 A and B), and between X. maculatus and a second species, X. couchianus. The X. maculatus JP 163 A and B parental lines have been separated in the laboratory for &#x2248;70 years and we were able to identify SNPs at a resolution of 1 SNP per 49 kb of transcriptome. In contrast, SNP polymorphisms between X. couchianus and X. maculatus species, which diverged &#x2248;5-10 million years ago, were identified about every 700 bp. Using 6524 transcripts with identified SNPs between the two parental species (X. maculatus and X. couchianus), we mapped RNA-seq reads to determine ASGE within F(1) interspecies hybrids. We developed an in silico X. couchianus transcriptome by replacing 90,788 SNP bases for X. maculatus transcriptome with the consensus X. couchianus SNP bases and provide evidence that this procedure overcomes read mapping biases. Employment of the in silico reference transcriptome and tolerating 5 mismatches during read mapping allow direct assessment of ASGE in the F(1) interspecies hybrids. Overall, these results show that Xiphophorus is a tractable vertebrate experimental model to investigate how genetic variations that occur during speciation may affect gene interactions and the regulation of gene expression.

Alleles↗

Exploiting the weak link: Ataxia-Telangiectasia Mutated dysfunction in oesophagogastric tumours.

ATM (ataxia-telangiectasia mutated) is a central regulator of the DNA damage response, coordinating double-strand break repair, checkpoint control, and cell fate decisions. Its disruption drives genomic instability and has been implicated across multiple tumour types. In oesophagogastric cancers, ATM alterations occur in a clinically relevant subset of cases, encompassing both somatic and germline events, and are associated with distinct molecular features including reduced co-occurrence with TP53 mutations and elevated homologous recombination deficiency scores. This narrative review synthesises published literature and publicly available genomic databases to examine ATM biology, the spectrum of ATM alterations across oesophageal adenocarcinoma, oesophageal squamous cell carcinoma, and gastric cancer subtypes, and the challenges of defining true ATM deficiency. The therapeutic implications of ATM dysfunction are evaluated across radiotherapy, platinum-based chemotherapy, ATR inhibition, and PARP inhibition. ATM alterations are detected in approximately 6% of tumours pan-cancer and in up to 10% of oesophagogastric cases. Defining ATM deficiency remains challenging, as immunohistochemistry, next-generation sequencing, and functional assays each carry distinct limitations. ATR inhibition emerges as the most consistently supported therapeutic strategy, with converging preclinical and early clinical evidence across oesophagogastric models. By contrast, available data do not support treating ATM deficiency as equivalent to BRCA-like homologous recombination deficiency, and PARP inhibitor monotherapy has not demonstrated consistent benefit. Prospective validation of functional ATM assays, histology-stratified trial design, and integration of genomic, protein-level, and functional evidence represent key priorities for translating ATM-guided strategies into oesophagogastric cancer practice.

Humans↗

Genomic profiling by circulating tumor DNA in patients with hormone receptor-positive/HER2-negative advanced breast cancer: Prevalence of actionable mutations across treatment lines.

INTRODUCTION: Plasma next-generation sequencing (NGS) is endorsed by ESMO as an alternative to tissue testing in advanced hormone receptor-positive, HER2-negative metastatic breast cancer (HR+/HER2- mBC), particularly after progression on endocrine therapy plus CDK4/6 inhibitors. However, prospective real-world data across distinct therapeutic contexts remain limited. PATIENTS AND METHODS: In this prospective observational study conducted within a nationwide cancer network in Brazil, centralized plasma NGS, and tissue NGS when available, was performed in two independent cohorts: prior to initiation of first-line endocrine therapy in the metastatic setting (Cohort 1) and at progression on endocrine therapy plus a CDK4/6 inhibitor (Cohort 2). The primary objective was to evaluate plasma-detected ESR1 mutation prevalence across these therapeutic contexts, and secondarily to assess other actionable drivers detected by plasma or tissue NGS. RESULTS: Among 86 collected plasma samples, 72 (84%) had evaluable NGS results (Cohort 1, n = 37; Cohort 2, n = 35). ESR1 mutations were identified in 18.9% of patients in Cohort 1 and 40.0% in Cohort 2, mostly at low variant allele fractions (<0.5%), corresponding to an absolute prevalence difference of 21.1 percentage points (95% CI, -0.2 to 40.3; P value=0.07). When considering any actionable alteration detected by plasma, including ESR1, PIK3CA, AKT1, PTEN, BRCA1, BRCA2, and ERBB2, prevalences were 43.2% and 68.6%, respectively (P value=0.04). Only four patients had ESR1 mutations identified in tissue, three in metastatic samples. Plasma-tissue concordance was higher for PIK3CA mutations (85.1%). CONCLUSION: Plasma NGS identified clinically meaningful ESR1 mutation rates across both contexts, supporting guideline-endorsed plasma-based genomic profiling in HR+/HER2- mBC.

CDK4/6 inhibitors↗

Primary Mitochondrial-Disorders-Associated Nephropathy in Adulthood.

Oxidative phosphorylation (OXPHOS) is the main source of cellular adenosine triphosphate (ATP) production and depends on proteins encoded by both mitochondrial and nuclear DNA (nDNA). Pathogenic variants affecting this dual genetic control cause primary mitochondrial disorders (MIDs), which follow either maternal inheritance when they affect mitochondrial DNA (mtDNA) or autosomal inheritance when they affect nuclear-encoded mitochondrial proteins. Once considered predominantly pediatric conditions, these disorders are increasingly recognized in adults where their clinical presentation is heterogeneous and frequently underdiagnosed, requiring the involvement of various medical specialties.Because of their high energy requirements, kidneys are particularly vulnerable to primary MIDs. Tubular epithelial cells rely on OXPHOS for solute transport, whereas podocytes require sustained ATP production to preserve the glomerular filtration barrier. Although kidney involvement in adult primary MIDs has long been regarded as rare, emerging data indicate that primary MIDs-associated nephropathy (MIDAN) is more common than previously appreciated, yet remains under-recognized, as a cause of adult kidney disease. Renal manifestations include a broad spectrum of glomerular disorders-predominantly focal segmental glomerulosclerosis (FSGS), often associated with diabetes mellitus and sensorineural hearing impairment-as well as tubulo-interstitial nephritis (TIN), which may present as an isolated renal phenotype or as part of a multisystemic disorder.Advances in next-generation sequencing, including mitochondrial genome sequencing and exome or whole-genome sequencing, are transforming the diagnostic approach to MIDAN. Improved recognition of mitochondrial etiologies in adults with unexplained glomerular or tubulo-interstitial kidney disease is essential to optimize diagnosis, management, and genetic counseling.

adult↗

Challenges of Using Circulating Tumour DNA: Insights from Advanced Prostate Cancer.

Precision oncology relies on integrating tumour fraction, variant allele frequency, clonal haematopoiesis of indeterminate potential assessment, pathogenicity, and clinical context into next-generation sequencing interpretation, enabling biologically informed and clinically meaningful treatment decisions while reducing the risk of overinterpreting nontumour or nonactionable genomic alterations.

Editorial↗

Paired Exome-Based Comprehensive Genomic Profiling and Germline Genetic Testing for Unselected Patients With Colorectal Cancer in a Multicenter Prospective Study.

BACKGROUND AND AIMS: Comprehensive genomic profiling (CGP) for tumors and germline genetic testing (GGT) inform precision therapy and clinical management of patients with colorectal cancer (CRC), and evidence is growing in support of universal paired CGP-GGT patient testing. However, the utility of combining CGP and GGT for early-stage CRC (ESC) and early-onset CRC (EOC) is unclear. METHODS: We performed a prospective, multisite study featuring GGT using an 80+ gene next-generation sequencing platform and exome-based CGP among CRC patients (unselected for age, stage, family history) receiving care at Mayo Clinic Cancer Centers between April 1, 2018, and March 31, 2020. RESULTS: A total of 150 CRC patients had GGT and exome-based CGP performed. ESC patients had an enrichment of high microsatellite instability and high tumor mutation burden. High microsatellite instability was also enriched in those with smoking history, and in tumors with mutated BRAF, homologous recombination deficiency, or at least 1 variant in the rat sarcoma virus pathway. Moreover, patients with smoking history were enriched in BRAF and other Tier 1 or 2 variants overall. Sixteen percent of patients harbored a pathogenic germline variant, most frequent being in Lynch syndrome genes. Paired GGT and CGP testing had high rates of clinically significant findings (&#x2248;70%) with the most frequent being high tumor mutation burden status. Pathway and mutational signature analysis revealed frequent CGP mutations in DNA repair and cell cycle pathways. CONCLUSION: These data suggest that universal, combined GGT-CGP increases clinical utility for EOC and ESC patients. This is key for EOC patients who tend to experience poorer outcomes. CGP-GGT expedites germline resolution for tumor mutations in hereditary cancer genes, reducing delays and facilitating identification of relevant therapies, clinical trials, and management recommendations.

Colorectal Cancer↗

First complete mitochondrial genome of Uzelothrips scabrosus (Thysanoptera: Uzelothripidae) provides insights into gene rearrangements and phylogenetic position within Terebrantia.

The family Uzelothripidae is represented by a single genus Uzelothrips and can be distinguished from others by the presence of whip-like antennae, a circular ventral sensorium on antennal segment III, a well-developed tentorium, and a membranous ovipositor. Here, we generated the first complete mitochondrial genome of Uzelothrips scabrosus (15,674&#xa0;bp) using next-generation sequencing to explore the gene rearrangements and phylogenetic relationships. It consists of 13 protein-coding genes, 22 transfer RNAs, two ribosomal RNAs, and two putative control regions. The genome exhibits strong AT bias (71.35%) with negative AT and GC skew. Codon usage analyses indicate a strong bias towards A/U-ending codons and influenced by both natural selection and mutation pressure. All PCGs were under purifying selection, with cox1 being the most conserved and nad4L the most variable. The gene order of the family Uzelothripidae is highly rearranged compared to the ancestral insect gene order. Comparative analysis revealed that gene block B was the most widely conserved, whereas the remaining gene blocks exhibited family or lineage-specific conservation patterns, reflecting extensive mitochondrial gene rearrangements during the evolution of the Thysanoptera. Moreover, 228 synapomorphic and 68 autapomorphic gene boundaries were identified across thysanopteran mitogenomes. Phylogenies indicated that the family Uzelothripidae is in a sister relationship with Stenurothripidae, and the Uzelothripidae&#xa0;+&#xa0;Stenurothripidae clade is sister to Thripidae. This study provides the first mitogenomic insights into Uzelothripidae and highlights the need for broader taxon sampling and nuclear genomic data to resolve deep evolutionary relationships within Thysanoptera.

Comparative analysis↗

Clinical and genetic analysis of a family with 16p11.2 microduplication syndrome and variable multisystem manifestations.

16p11.2 microduplication syndrome (OMIM #614671) is a pathogenic recurrent copy-number gain at the 16p11.2 locus and is associated with variable expressivity across neurodevelopmental, growth, and medical phenotypes. Gastrointestinal symptoms have been reported in carrier cohorts, but detailed documentation of gastrointestinal motility and neuromuscular findings remains limited. We performed clinical and genetic analyses in a multigenerational family in which the proband (III1) presented with limb muscle pain, exercise intolerance, and chronic gastrointestinal symptoms. Next-generation sequencing (NGS), low-pass whole-genome sequencing (lpWGS)-based CNV analysis, Sanger sequencing, and qPCR validation identified a 0.8&#xa0;Mb microduplication at 16p11.2 (BP4-BP5), involving 44 genes including TBX6, inherited from the mother (II2). The proband's clinical manifestations included developmental delay, pointed chin, low body mass index, gastrointestinal dysfunction (chronic abdominal pain, diarrhea, esophageal motility disorder, and rectal prolapse), forward-leaning gait, mild scoliosis, and limb muscle atrophy with inflammatory muscle involvement. Four family members (II2, III1, III2, and III4) carried the microduplication, but their available clinical features varied in severity and system involvement. The proband's twin brother (III2) had left ear deafness and epilepsy, individual II2 had blindness from cone-rod dystrophy, and III4 showed more pronounced scoliosis. This family provides a detailed clinical and genetic description of 16p11.2 microduplication carriers with prominent gastrointestinal motility and neuromuscular manifestations, thereby enriching the clinical characterization of this recurrent CNV and supporting substantial intrafamilial phenotypic heterogeneity.

16p11.2 microduplication syndrome↗

Further description of the phenotypic spectrum of neuronal ceroid lipofuscinosis type 11.

PURPOSE: Ceroid lipofuscinosis type 11 (CLN11) is a very rare disease, being reported in only 13 unrelated families so far. Further reports are necessary to comprehend the clinical phenotype of this condition. This article aims to report 9 additional cases of CLN11 from 9 unrelated Latin American families presenting with relatively slow disease progression. METHODS: This was a retrospective observational study including patients with CLN11. Patients were identified through an active search for granulin precursor gene (GRN) pathogenic variants across the entire database of next-generation sequencing of a commercial laboratory and by contacting attending physicians to check for clinical and radiologic findings compatible with a neuronal ceroid lipofuscinosis phenotype. RESULTS: Nine CLN11 patients from unrelated families were evaluated. Age of onset varied between 3 to 17 years. The most common findings were visual impairment, cerebellar ataxia, seizures, myoclonus, and cognitive decline. One patient had a previously unreported finding of cervical, perioral, and tongue myoclonus. Most of the patients were able to walk unassisted after an average of 14.2 years (SD 4.76 y) from disease onset. CONCLUSION: We describe 9 new cases of a very rare type of neuronal ceroid lipofuscinosis (CLN11) from Latin America with a recurrent p.(Gln257ProfsTer27) and a novel p.(Cys83Ter) nonsense variant. Our findings suggest that a slowly progressive neuronal ceroid lipofuscinosis might be a clue for the diagnosis of CLN11.

Humans↗

Clinical and genetic variant re-analysis among pediatric probands undergoing genetic testing for arrhythmia syndromes.

BACKGROUND: Despite increases in genetic testing, longitudinal data regarding changes in diagnostic yield and variant reclassification for inherited arrhythmia syndromes are limited. OBJECTIVE: Determine longitudinal changes in diagnostic yield and variant classification. METHODS: Single-center retrospective study of probands <18 years undergoing genetic testing for suspected inherited cardiac conditions associated with arrhythmias, 2007 to 2018. Variants were classified as diagnostic (pathogenic/likely pathogenic), non-diagnostic (benign/likely benign [B/LB]), or variants of uncertain significance (VUS). Variant reclassification was performed in October 2023 using VarSome and American College of Medical Genetics criteria. We evaluated results by era (early 2007-2013 vs. later 2014-2018, coinciding with Sanger and next-generation sequencing, respectively) and by likelihood of disease based on clinical evaluation. RESULTS: Of 306 probands, initial testing was 23.2% diagnostic, 55.6% non-diagnostic (33.7% no variant, 21.9% B/LB), and 21.2% VUS. When comparing eras, diagnostic yield decreased (34.1%-15.3%), VUS increased (9.3%-29.9%), and non-diagnostic remained similar (55% to 57%). Variants for 22.7% (46/203) of probands with &#x2265;1 variant changed: 9.9% of diagnostic variants (7/71) downgraded to VUS or non-diagnostic, and 60.0% of VUS changed (23.1% upgraded, 36.9% downgraded). B/LB variants did not change. Probands with higher disease likelihood had 6-times the odds of diagnostic results compared to lower disease likelihood, regardless of era (odds ratio 6.3, 95% confidence interval 3.2-12.4, P < .0001). CONCLUSION: Variant reclassification led to changes in 23% of probands, both downgrading and upgrading status, even among probands initially thought to be pathogenic. When comparing later to earlier eras, VUS variants increased while diagnostic yield decreased. Findings support the need for variant re-interpretation and periodic reclassification over time.

Humans↗

Genomic evidence of active circulation of Orthobunyavirus in Ecuador.

BACKGROUND: Between 2023 and 2025, the largest Oropouche fever epidemic recorded in history unfolded across Brazil seeding cases throughout Latin America. In 2024, three cases of Oropouche fever were reported in Ecuador. METHODS: An Oropouche fever case detected in Bol&#xed;var Province in June 2024 was preliminarily diagnosed as Oropouche virus (OROV) through RT-qPCR and was further processed using next-generation sequencing. RESULTS: Segments L and S of this virus forms a monophyly with another sequence circulating in Ecuador in April 2024 (i.e. PQ863772.1 isolate Ecuador traveler), with an uncertain province origin. Both sequences differ from previous OROV Ecuadorian sequences detected in 2016 and from the OROV strain driving the 2023-2025 epidemic in Brazil. CONCLUSIONS: Orthobunyavirus oropoucheense has an endemic circulation in Ecuador. Genomic surveillance of Orthobunyavirus in Ecuador and other regions should be actively pursued-independent of epidemics-to anticipate potential zoonotic outbreaks.

Adult↗

Severe hypercholesterolemia in a pediatric cohort: Familial homozygous and autosomal recessive hypercholesterolemia.

BACKGROUND: Familial hypercholesterolemia (FH) is a genetic disorder characterized by impaired clearance of low-density lipoprotein cholesterol (LDL-C), leading to severe hypercholesterolemia and increased risk of premature cardiovascular disease (CVD). Our study aims to describe and compare the clinical, biochemical, and genetic profiles of pediatric patients diagnosed with FH based on LDL-C levels exceeding 400 mg/dL (10.4 mmol/L) and confirmed by biallelic pathogenic variants in low-density lipoprotein receptor (LDLR) or low-density lipoprotein receptor adapter protein-1 (LDLRAP1) genes. METHODS: This retrospective cohort study included 39 pediatric patients diagnosed with FH at a tertiary care center. Clinical data were analyzed, including age at diagnosis, family history, lipid profile, presence of xanthomas, and cardiovascular complications. Molecular analysis was conducted using next-generation sequencing (NGS) and Sanger sequencing to confirm pathogenic variants. Statistical comparisons were performed between the LDLR and LDLRAP1 variant groups regarding lipid profiles, treatment response, and cardiovascular outcomes. RESULTS: Among 39 patients, 32 and 7 had pathogenic variants in LDLR and LDLRAP1 genes, respectively. Genetic analysis identified 27 unique pathogenic variants in LDLR (including 5 novel mutations) and 4 in LDLRAP1 causal for autosomal recessive hypercholesterolemia (ARH), highlighting the molecular diversity of FH. Compared to the LDLR variant group, LDLRAP1 variant patients had significantly lower untreated LDL-C levels (640.0 &#xb1; 155.6 mg/dL [16.6 &#xb1; 4.0 mmol/L] vs 506.9 &#xb1; 130.1 mg/dL [13.1 &#xb1; 3.4 mmol/L], P = .026] and showed a superior response to lipid-lowering therapy (LLT), with a greater percentage (70.6% &#xb1; 12.0%) reduction in LDL-C levels (P = .015). While xanthomas were present in 62.5% of LDLR variant patients, they were less frequent (42.9%) in the LDLRAP1 group (P = .107). Cardiovascular complications were observed exclusively in LDLR variant patients. Fourteen patients required lipoprotein apheresis (LA), and one underwent liver transplantation due to severe aortic stenosis. CONCLUSION: This study highlights the importance of genetic testing in differentiating classical semidominant homozygous FH from ARH, given their phenotypic overlap but distinct treatment responses. LDLRAP1 variant patients with ARH exhibit better LDL-C reductions with conventional LLT, suggesting a milder phenotype. Early diagnosis, aggressive LLT, and novel treatments are essential to mitigate cardiovascular risk. Future studies with larger cohorts and long-term follow-ups are needed to refine treatment strategies for pediatric FH.

Humans↗