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Background: Precision nutrition and nutrigenomics have emerged as promising strategies to personalize dietary interventions according to individual genetic, metabolic, and molecular characteristics. However, the potential of nutrigenomic-guided nutraceutical interventions to modulate biological aging pathways remains poorly characterized. Objective: This study aimed to map and synthesize the available evidence from human studies evaluating personalized nutraceutical interventions based on nutrigenomic approaches and their effects on biomarkers associated with biological aging. Methods: A scoping review was conducted following the Joanna Briggs Institute methodology and PRISMA-ScR guidelines. PubMed/MEDLINE, Embase, Scopus, and Web of Science were searched for studies published between 2021 and 2026. Eligible studies included adults aged ≥18 years receiving personalized nutraceutical interventions informed by genetic, genomic, metabolomic, or other molecular data. Outcomes included biomarkers of cellular aging, inflammation, oxidative stress, immunometabolism, and related pathways. Results: Twenty-one studies were included. Interventions involved omega-3 fatty acids, polyphenols, Nigella sativa, vitamin D, methyl-donor micronutrients, fermented papaya preparation, and other nutraceutical preparations and functional food-based interventions. Four major themes emerged: multi-omic stratification approaches, biological aging biomarkers, redox-inflammatory modulation, and applications in metabolic disorders. Most studies demonstrated favorable effects on intermediate molecular biomarkers, including inflammatory cytokines, oxidative stress markers, lipid metabolism, endothelial function, and DNA methylation signatures. However, evidence directly demonstrating slowing of biological aging through validated biomarkers such as epigenetic clocks or telomere dynamics remains limited. Conclusions: Personalized nutraceutical interventions exhibit biological plausibility for modulating pathways associated with healthy aging. Nevertheless, robust longitudinal studies incorporating validated biomarkers of biological aging and clinically meaningful outcomes are needed before their widespread implementation in precision medicine. Full article

Familial hypercholesterolemia (FH) has been associated with an increased risk of major depressive disorder (MDD), but their shared molecular signatures remain unclear. This study aimed to identify candidate genes associated with FH-MDD co-occurrence through integrative transcriptomic analysis, machine learning, summary-data-based Mendelian randomization (SMR), and clinical validation. Transcriptomic datasets from the Gene Expression Omnibus were analyzed, including GSE6054 and GSE13985 for FH and GSE98793 for MDD. Differential expression analysis and weighted gene co-expression network analysis were used to identify shared candidate genes. Candidate biomarkers were screened using least absolute shrinkage and selection operator regression and Random Forest algorithms, followed by the construction of an exploratory nomogram. SMR analysis was performed to assess genetically supported associations between candidate-gene expression and MDD risk. Selected genes were validated by PBMC RT-qPCR in an independent four-group clinical cohort comprising healthy controls and participants with FH, MDD, or co-occurring FH and MDD. Flow cytometry was subsequently used to characterize the peripheral CD4+ T-cell profile. A total of 54 shared candidate genes were identified. CD4, MRPS21, and CRTC2 were selected by machine learning and incorporated into the nomogram, which showed good discrimination in the training set and moderate performance in external validation. Immune infiltration and enrichment analyses highlighted monocyte alterations, reduced T-cell-related signals, and enrichment of T-cell receptor and TNF-mediated pathways. SMR analysis indicated that genetically predicted higher CD4 expression was inversely associated with MDD risk, whereas RT-qPCR showed higher CD4 expression in patients with FH-MDD. Flow-cytometric analysis showed that FH-MDD participants had a higher circulating CD3+CD4+ T-cell proportion, an increased effector-memory CD4+ T-cell proportion, and a higher proportion of HLA-DR+ CD4+ T cells than participants in the comparison groups. These findings suggest that CD4 may represent a promising immune-related candidate signature associated with the co-occurrence of FH and MDD, warranting further functional validation. Full article

Background: Inherited metabolic disorders (IMDs) are a heterogeneous group of genetic diseases, some of which require lifelong disease-specific dietary management. Children with phenylketonuria (PKU), organic acidemias (OAs), and glycogen storage diseases (GSDs) are particularly susceptible to nutritional imbalances and metabolic disturbances that may adversely affect bone metabolism and skeletal health. However, data regarding bone turnover markers and bone health in these pediatric IMD populations remain limited. Objective: This study aimed to evaluate bone metabolism by assessing biochemical parameters, bone turnover markers, and bone mineral density in children with PKU, OA, and GSD receiving long-term dietary treatment. Methods: This cross-sectional study included 95 children, comprising 25 patients with PKU, 20 patients with organic acidemias, 20 patients with glycogen storage diseases, and 30 healthy age-matched controls. Demographic characteristics, anthropometric measurements, and dietary intake were recorded. Biochemical evaluation included serum calcium, phosphorus, alkaline phosphatase (ALP), parathyroid hormone (PTH), and 25-hydroxyvitamin D levels. Bone turnover was assessed using C-terminal telopeptide of type I collagen (CTX), procollagen type I N-terminal propeptide (P1NP), and osteocalcin (OC) levels. Bone mineral density was evaluated by dual-energy X-ray absorptiometry (DXA). Results: Age and sex distributions were similar among the groups. Height was lower in OA than in controls and PKU, and in GSD than in PKU; weight and BMI were lower in both OA and GSD than in controls and PKU (p < 0.05). Significant differences were observed in dietary energy and macronutrient intake according to disease-specific nutritional regimens. Serum calcium, phosphorus, and 25-hydroxyvitamin D levels were significantly lower in all IMD groups compared with healthy controls (p < 0.001). ALP and PTH levels were significantly higher in PKU, OA, and GSD patients than in controls (p < 0.001). Among bone turnover markers, P1NP and osteocalcin levels significantly differed among groups, with the highest values observed in PKU patients (p = 0.006 and p = 0.028, respectively). CTX levels did not significantly differ among the groups (p = 0.183). DXA Z-scores were significantly lower in all IMD groups than in controls, with the lowest mean Z-scores observed in GSD patients. Conclusions: Children with PKU, OA, and GSD receiving long-term dietary treatment exhibited significant alterations in bone metabolism, characterized by lower vitamin D, calcium, and phosphorus levels, higher ALP and PTH concentrations, differences in bone formation markers, and lower DXA Z-scores compared with controls. Significant differences were observed in the bone formation markers P1NP and osteocalcin, whereas CTX levels remained comparable among the study groups. These findings underscore the importance of regular assessment of bone health and optimization of nutritional management in children under dietary treatment, while acknowledging that disease-specific mechanisms of skeletal involvement may differ among these conditions. Full article

Background: Brain MRI in patients with autism spectrum disorder (ASD) is generally considered when additional neurologic, developmental, or syndromic concerns warrant structural evaluation. In the study practice, ASD alone was not used as the reason to obtain MRI. We examined documented MRI use and broad result coding while explicitly separating selection for imaging from abnormal-result status. Methods: This retrospective specialty-practice cohort included 1884 patients with ASD. The primary outcome was the proportion of documented MRI examinations coded abnormal. Secondary analyses examined associations of age, sex, seizure history, EEG status, and genetic test status with abnormal versus normal MRI coding and with documented MRI utilization. MRI categories and the pediatric restriction were exploratory and sensitivity analyses. Results: An MRI result was recorded for 704 patients (37.4%; 95% CI 35.2–39.6); 322 were coded abnormal (45.7%; 95% CI 42.0–49.5). The abnormal-result models had low in-sample discrimination (AUC 0.528 and 0.553), and adjusted confidence intervals for all measured variables included 1.00; these results do not demonstrate equivalence between clinical groups. Seizure history was associated with documented imaging in the full cohort (aOR 2.47, 95% CI 1.94–3.14), and abnormal EEG was associated in the exploratory complete-case utilization model (aOR 2.83, 95% CI 1.93–4.14). Conclusions: Broad MRI abnormalities were frequent among patients selected for imaging because of additional clinical concerns, but a broad abnormal code is not equivalent to clinically actionable yield. The routinely captured variables available in this dataset were insufficient to distinguish abnormal from normal MRI coding. These findings favor individualized MRI decisions based on the clinical question prompting imaging and motivate future studies with richer neurologic and developmental phenotyping. Full article

Background/Objectives: Wilson disease (WD) is an autosomal recessive disorder of copper metabolism caused by pathogenic variants in the ATP7B gene. Early diagnosis and appropriate treatment are essential for preventing irreversible complications. This study demonstrated the clinical utility of integrated high-throughput genomic analysis for molecular diagnosis and genetic counseling in a large Thai family affected by WD. Methods: A 32-year-old woman with clinical features suggestive of WD underwent clinical, biochemical, and molecular genetic evaluations, including sequencing of the entire ATP7B gene and SNP microarray. Fluorescent PCR followed by capillary electrophoresis was used for segregation analysis in available family members. SNP microarray analysis and whole-exome sequencing were performed on the proband’s husband to identify pathogenic variants in the ATP7B gene and other disease-associated genes for reproductive risk assessment. Results: The proband presented with hepatic dysfunction, Kayser–Fleischer rings, low serum ceruloplasmin, and a family history of fatal liver disease. She also developed progressive weakness, with nerve conduction findings consistent with axonal sensorimotor polyneuropathy predominantly affecting the lower limbs. Sequencing identified a novel homozygous 28-bp splice-junction deletion, c.4022-24_4025del, which disrupted the canonical splice acceptor site at the intron 19/exon 20 boundary and was classified as pathogenic variant. Segregation analysis confirmed carrier status in the proband’s father and identified heterozygous carrier or homozygous wild-type status among her living siblings. SNP microarray analysis revealed a 46.7 Mb copy-neutral long contiguous stretch of homozygosity (CN-LCSH) encompassing ATP7B, with CN-LCSH regions accounting for 2.046% of the total autosomal genome. These findings potentially reflected segmental uniparental isodisomy or identity by descent, while the overall homozygosity pattern did not support recent consanguinity. Combined genomic analyses of the proband’s husband revealed no pathogenic or likely pathogenic ATP7B variants. Based on the available testing, all offspring are expected to be heterozygous carriers, and the risk of an affected child is considered very low. Conclusions: This study highlights the value of integrated genomic analysis for molecular diagnosis, cascade testing, and reproductive risk counseling. Further functional studies should be conducted to validate their pathogenicity. Full article

Developmental disorders often arise from complex interactions between genetic variation and environmental factors, yet the molecular mechanisms underlying gene-gene (G × G) and gene-environment (G × E) interactions remain poorly understood. Mouse embryonic eyelid closure provides a genetically tractable in vivo model for investigating these mechanisms. Eyelid closure requires coordinated epithelial migration and cytoskeletal remodeling orchestrated by interconnected signaling pathways. Among these pathways, MAP3K1 functions as a critical signaling hub that integrates inputs from S1PR-RHOA-ROCK and other upstream regulators to activate JNK and promote eyelid closure. Genetic studies show that multiple components within the GPCR-RHOA-ROCK-MAP3K1-JNK network cooperate to maintain developmental robustness. Reducing the activity of pathway components dose-dependently impairs eyelid closure and produces the characteristic eye-open-at-birth (EOB) phenotype. Environmental factors also converge on this network. Although exposure to dioxin does not impair eyelid closure in wild-type embryos, it induces EOB in embryos harboring otherwise phenotypically silent mutations in the MAP3K1 network, such as Map3k1^+/−, Jnk1^−/− and S1pr2^−/−. These findings identify the MAP3K1 pathway as a point of convergence of genetic and environmental signals and establish embryonic eyelid closure as a powerful model for elucidating molecular mechanisms underlying developmental robustness, susceptibility and resilience. Full article

PHARC (polyneuropathy, hearing loss, ataxia, retinitis pigmentosa and cataracts) syndrome is a rare neurodegenerative inherited disorder characterized by a spectrum of these clinical phenotypes. Due to the considerable heterogeneity in the age of onset of the different clinical features and the similarities with other conditions, it is often misdiagnosed. Variants in the ABHD12 gene have been identified as a genetic cause of PHARC syndrome and are predicted to result in loss-of-function or severely reduced protein synthesis. ABHD12 (α/β-hydrolase domain-containing protein 12) is responsible for the breakdown of very-long-chain lysophosphatidylserines (VLC-lyso-PS). When ABHD12 is dysfunctional, VLC-lyso-PS accumulates in the brain, producing inflammation. In this study, the clinical phenotypes of five patients with molecularly confirmed ABHD12 pathogenic variants from Moorfields Eye Hospital together with those of 64 patients reported in the literature were analyzed to investigate genotype–phenotype correlations. We report a novel variant c.985del p.(His329Thrfs*57) associated with PHARC syndrome. Moreover, patients with two null variants in ABHD12 manifest more of the clinical features of PHARC syndrome than those with at least one missense variant. Our study shows the importance of a complete clinical and genetic diagnosis to enable accurate diagnosis and genetic counselling for affected individuals. Full article

Autism spectrum disorder (ASD) is a neurodevelopmental disorder characterized by impaired social interactions, communication deficits, and excessive repetitive behaviors. While ASD has a strong genetic basis, growing evidence suggests that epileptic seizures may serve as environmental risk factors for ASD development. The high comorbidity between epilepsy and ASD (20–30%) suggests potential shared neurobiological mechanisms, yet the causal relationship remains poorly understood. To investigate the causal role of seizures in the development of ASD-like pathology, we exposed adolescent mice (3 weeks old) to electroconvulsive seizures (ECS) for 10 consecutive days. This repeated ECS exposure led to the emergence of autistic-like behaviors including significantly decreased sociability, increased repetitive self-grooming, enhanced marble burying behavior, and anxiety-like behaviors, without affecting general locomotor activity. Additionally, repeated exposure to ECS induced significant changes in glutamatergic neurotransmission in the mice’s prefrontal cortex and hippocampus, brain regions critically involved in social cognition and behavioral regulation. Interestingly, these changes occurred without alterations in other excitatory/inhibitory neuronal markers, suggesting a specific impact on glutamate receptor expression rather than a general disruption of excitatory/inhibitory balance. These findings suggest that repeated seizures may contribute to ASD-like symptoms by specifically affecting key glutamatergic neurotransmitter systems, providing insights into the neurobiological mechanisms underlying the comorbidity between epilepsy and autism. In addition, repeated ECS differentially regulated histone deacetylase (HDAC) transcripts in a region-specific manner and produced seizure-intensity-dependent transcriptomic signatures. Full article

Nicotinamide adenine dinucleotide (NAD⁺) is a fundamental metabolic cofactor and signaling molecule that supports redox reactions, DNA repair, chromatin regulation, stress adaptation, inflammation, and neuronal maintenance. Age-associated NAD⁺ decline has been implicated in brain aging and neurodegenerative disorders, but the causal node and limiting compartment differ across tissues and disease states. Nicotinamide mononucleotide adenylyltransferase 1 (NMNAT-1) catalyzes the final step in NAD⁺ biosynthesis and represents the major nuclear isoform of the mammalian NMNAT family. Direct human genetic evidence establishes NMNAT-1 as a causal gene in inherited retinal degeneration, whereas evidence linking endogenous NMNAT-1 to broader brain aging or sporadic neurodegeneration is mainly convergent preclinical, preliminary, or indirect. Beyond NAD⁺ synthesis, biochemical and Drosophila studies suggest possible chaperone-like and proteostasis-supporting functions, but a separable NAD⁺-independent function of endogenous mammalian NMNAT-1 has not yet been established in vivo. Here, we review the molecular structure, localization, and regulation of NMNAT-1, emphasizing calibrated distinctions among catalytic nuclear NAD⁺ supply, engineered axonal protection, pathway-adjacent NAD⁺ interventions, and putative non-catalytic protection. We further discuss how NMNAT-1 dysfunction may contribute to aging-associated genomic instability, neuroinflammation, synaptic impairment, retinal degeneration, selected neurodegenerative models, and glioma biology. Finally, we evaluate therapeutic strategies targeting NMNAT-1 and NAD⁺ pathways, noting that no human trial has yet established efficacy for an NMNAT-1-directed neurological therapy. A compartment-aware and evidence-stratified view is therefore essential for translating NMNAT-1 biology into interventions for age-related neural disease. Full article

Persistent Müllerian duct syndrome (PMDS) is a rare disorder of sex development characterized by the persistence of Müllerian duct derivatives in genetically and phenotypically male animals. This report describes the clinical presentation, diagnostic work-up, surgical management, histopathological findings, and cytogenetic characterization of a 9-year-old intact male Schnauzer dog presented with a 3-day history of progressively worsening vomiting, diarrhea, unilateral testicular enlargement, oliguria, and dysuria. Diagnostic evaluation included abdominal radiography, ultrasonography, exploratory laparotomy, histopathology, and cytogenetic analysis using R-replicative banding after bromodeoxyuridine incorporation. Imaging and surgical exploration revealed cryptorchidism, persistent Müllerian duct derivatives, including uterine horn-like structures, and an abnormal gonadal structure. Histopathological examination confirmed severe seminiferous tubular atrophy, persistence of Müllerian-derived tissues, and a unilateral Sertoli cell tumor. Cytogenetic analysis demonstrated a normal male karyotype (78,XY) without evidence of chromosomal mosaicism or structural abnormalities, supporting the diagnosis of a 78,XY disorder of sex development and excluding major chromosomal defects. This case highlights the importance of integrating clinical evaluation, diagnostic imaging, histopathology, and cytogenetic analysis to identify findings compatible with PMDS and emphasizes that this condition should be considered in the differential diagnosis of cryptorchid male dogs presenting with reproductive tract abnormalities or associated testicular neoplasia. Full article

Background/Objectives: Achondroplasia is the most common genetic skeletal dysplasia associated with disproportionate short stature and is primarily caused by gain-of-function variants in the fibroblast growth factor receptor 3 (FGFR3) gene. Constitutive FGFR3 activation disrupts growth plate homeostasis and endochondral ossification through complex alterations in chondrocyte proliferation, differentiation, hypertrophy, extracellular matrix organization, and intracellular signaling. The increasing understanding of these mechanisms has enabled the transition from exclusively supportive management toward disease-modifying and precision-based therapeutic strategies. This narrative review aimed to critically synthesize current evidence on the genetic basis, molecular pathogenesis, growth plate abnormalities, and current and emerging targeted therapies in achondroplasia. Methods: A narrative literature review was conducted using PubMed/MEDLINE, Scopus, and Web of Science Core Collection, with Google Scholar used as a supplementary source, together with manual screening of the reference lists of relevant original studies, clinical trials, reviews, consensus documents, and clinical guidelines. The principal literature search covered publications from January 2010 to March 2026, while selected seminal primary studies published before 2010 were included when necessary to document the original identification of pathogenic FGFR3 variants and foundational mechanisms of FGFR3-mediated growth plate regulation. Particular emphasis was placed on FGFR3 variants, receptor activation mechanisms, growth plate dysfunction, intracellular signaling pathways, vosoritide, C-type natriuretic peptide-based therapies, FGFR3 inhibitors, ligand–receptor blockade, drug repurposing, Wnt/β-catenin modulation, and gene-based therapeutic approaches. Results: Achondroplasia is characterized by marked molecular homogeneity, with the recurrent p.Gly380Arg substitution accounting for most cases. Mutant FGFR3 displays sustained activity through partial ligand independence, enhanced receptor dimerization and kinase activation, increased receptor stability, and reduced degradation. Excessive signaling through MAPK/ERK, STAT, PI3K/AKT, IHH/PTHrP, and related pathways impairs chondrocyte proliferation and hypertrophic differentiation, alters extracellular matrix turnover, disrupts primary cilium function, and reduces longitudinal bone growth. Vosoritide provides clinical proof that pharmacological modulation of FGFR3-related signaling can improve growth velocity. Additional therapeutic strategies under clinical or preclinical investigation include long-acting CNP analogues, selective FGFR inhibitors, decoy receptors, RNA aptamers, repurposed drugs, Wnt/DKK1 pathway modulation, and gene- or enhancer-targeted interventions. Conclusions: Achondroplasia is increasingly understood as a disorder of dysregulated growth plate signaling rather than solely a condition of reduced stature. Although vosoritide has established the feasibility of disease-modifying treatment, substantial uncertainty remains regarding final adult height, skeletal proportionality, cranio-spinal development, orthopedic outcomes, and long-term safety. Future progress will depend on mechanistically informed therapeutic combinations, improved biomarkers, advanced cellular and animal models, and long-term clinical and real-world evidence. Full article

Microphthalmia, anophthalmia and ocular coloboma (MAC) are rare developmental eye disorders. Although over 100 causative genes have been identified, the molecular spectrum and genotype–phenotype correlations remain incompletely understood, particularly in genetically diverse populations. We set out to molecularly characterize MAC in the Israeli population. Forty-seven MAC-affected individuals from 43 unrelated families were enrolled. DNA of all probands was subjected to whole exome sequencing. The most common phenotype was microphthalmia (64% of patients). Definite or possible molecular diagnoses were achieved in 13/43 probands (30%) and involved 10 different genes (MFRP, SMO, GJA8, SOX2, RARB, TSPAN12, SHH, PTPN11, BEST1, and TP63). An in vitro splicing assay was used to explore the pathogenicity of a variant in the SMO gene. Following stringent filtering of exome data, 226 rare possibly pathogenic variants were identified in 218 genes not previously associated with MAC. The rate of molecular diagnosis achieved in this Israeli MAC cohort is similar to the reported range in other studies. The results further demonstrate the genetic heterogeneity of MAC, while supporting the involvement of complex inheritance and/or environmental factors in many of the cases. Further studies are required to reveal these underlying etiological factors, and to support the novel genotype–phenotype associations suggested here. Full article

Because human infertility can arise from genetic, molecular, cellular, anatomical, and endocrine abnormalities, in vitro gametogenesis has become an important area of reproductive research. New developing technology involving the generation of human primordial germ cell-like cells (hPGCLCs) from induced pluripotent stem cells (hIPSCs) might assist with understanding early germ cell development (specification, migration, gametogenesis, and epigenetic reconstitution), as well as provide a solution for infertility and hereditary disorders. Given that human primordial germ cells (PGCs) are still not well characterized at a molecular level, we present a practical workflow to robustly and efficiently induce hPGCLCs from human pluripotent stem cells (hPSCs) XX and XY cell lines. This protocol describes the hPGCLC specification of hPSCs through sequential induction with Activin A for 2 days and BMP4 for 6 days in 2D and 3D culture systems. Induction of hPSCs into hPGCLCs demonstrated expression of early primordial germ cell markers, including PRDM1, NANOS3, DAZL, STELLA, SOX17, SSEA1, and cKIT, on the 8th day of hPGCLC generation. We described the protocol for generating early hPGCLCs, which provides an opportunity for further investigations into maturation into late germ cells and a chance to overcome a meiotic block to obtain haploid gametes in vitro. Full article

Major airway diseases, including chronic obstructive pulmonary disease (COPD), asthma, bronchiectasis and chronic rhinosinusitis without nasal polyps (CRSsNP), frequently coexist and share inflammatory, epithelial and remodeling features. However, whether these clinically distinct airway disorders are driven by a unified genetic liability and how this shared liability maps to disease-relevant tissues, genes and immune-regulatory programs remain incompletely understood. We integrated GWAS summary statistics for COPD, asthma, bronchiectasis and CRSsNP using linkage disequilibrium score regression, local genetic correlation analysis and Genomic structural equation modeling. A latent shared airway disease factor, termed gAirwayDisease, was constructed to capture common genetic liability across the four conditions. We then applied an integrative functional genomics framework, including gsMap spatial enrichment, PoPS gene prioritization, MAGMA gene-set enrichment, GTEx v8 lung MTWAS, OneK1K and DICE immune-cell MTWAS, scMORE regulon analysis and phenome-wide Mendelian randomization. All six airway disease pairs showed positive genetic correlations, with estimates ranging from 0.508 to 0.685. Genomic SEM supported a single shared factor, with positive standardized loadings for COPD, asthma, bronchiectasis and CRSsNP and excellent model fit. Spatial mapping localized gAirwayDisease-associated signals to airway- and epithelial-associated anatomical domains. PoPS prioritized immune and airway-relevant genes, including SMAD3, GATA3, IL1R1, RUNX3 and STAT6, while MAGMA enrichment highlighted B-cell activation, T-cell activation and transcriptional regulatory pathways. Lung MTWAS identified SLC9A2 and ORMDL3 as top genetically regulated expression signals. OneK1K immune-cell MTWAS highlighted recurrent IL18R1 associations across CD4 and CD8 T-cell subsets. scMORE further identified 36 significant regulon–cell type pairs across dendritic cells, B cells, monocytes, T cells and NK cells, including BCL11A, TCF4, KLF4, RUNX1 and STAT4 regulons. MR-PheWAS linked genetically predicted gAirwayDisease to respiratory, allergic, lung function and immune-related traits. This study defines gAirwayDisease as a genetically informed latent factor capturing shared liability across major airway diseases. Integrated functional genomic analyses highlight airway epithelial and immune regulatory programs associated with shared disease susceptibility and prioritize candidate genes and regulons for future experimental validation. Full article

Background/Objectives: Malignant hyperthermia (MH) is a life-threatening pharmacogenetic disorder of skeletal muscle primarily associated with pathogenic variants in RYR1; however, a substantial proportion of MH-susceptible individuals lack identifiable variants in known genes. This study aimed to identify novel genetic contributors in Ca²⁺-induced Ca²⁺ release (CICR)-positive patients without RYR1 variants and to evaluate their functional relevance. Methods: Among 29 CICR-positive individuals without pathogenic variants identified by gene panel testing, five patients underwent whole-exome sequencing (WES). In one family, heterozygous variants in ANO5 (p.Arg547Gln) and ORAI3 (p.Arg287Cys) were identified. To evaluate their functional significance, intracellular Ca²⁺ dynamics were analyzed in primary myotubes derived from Case 165, an affected individual carrying both variants, and compared with those from CICR-negative controls and CICR-positive patients harboring RYR1 variants. Results: Myotubes derived from Case 165 demonstrated enhanced sensitivity to caffeine and 4-chloro-m-cresol, elevated resting intracellular Ca²⁺ levels, and greater Ca²⁺ reduction under Ca²⁺-free conditions compared with CICR-negative controls, resembling the phenotype observed in the RYR1 variant group. In contrast, dantrolene-induced Ca²⁺ reduction was significantly greater only in the RYR1 variant group. Conclusions: These findings suggest that ANO5 and ORAI3 variants may contribute to abnormal Ca²⁺ regulation in MH-susceptible individuals without RYR1 mutations and highlight the importance of combining genomic analysis with functional validation to identify novel genetic contributors to MH susceptibility. Full article