Search Results (91)

Background: Retinal and optic nerve disorders are a leading cause of irreversible visual impairment worldwide. Advances in molecular genetics—including next-generation sequencing, genome-wide association studies, and gene-based therapeutic technologies—have reshaped understanding of both inherited and complex retinal diseases. However, translating genetic discovery into sustained clinical benefit remains biologically and practically constrained. Methods: A structured literature search was conducted using PubMed and Scopus to identify relevant studies published between 2015 and 2025. The search focused on molecular genetics, epigenetic modulation, mitochondrial biology, and translational applications in inherited retinal dystrophies and selected complex retinal diseases, prioritizing high-impact original research and systematic reviews addressing diagnostic innovation and therapeutic development. Results: Inherited retinal dystrophies represent the most advanced model of precision ophthalmology, with diagnostic yields approaching 70–80% in well-characterized cohorts. Gene augmentation and genome-editing strategies have demonstrated proof-of-concept efficacy, yet clinical benefit depends on residual cellular viability, delivery efficiency, and durability of expression. Emerging platforms include AAV-mediated gene transfer, in vivo CRISPR-based editing, RNA-directed splice modulation, and mitochondrial-targeted approaches. Persistent barriers include unresolved non-coding and structural variants, variant interpretation uncertainty, and endpoint selection in clinical trials. In contrast, complex retinal diseases such as glaucoma, age-related macular degeneration, and pathological myopia reflect polygenic susceptibility interacting with environmental and aging-related factors. Although polygenic risk scores refine probabilistic prediction, their utility is limited by ancestry bias and incomplete predictive performance. Epigenetic and mitochondrial mechanisms further modulate disease expression but remain largely non-actionable in routine practice. Conclusions: Retinal genetics has progressed from gene discovery to early therapeutic implementation. Future advances will depend on improved variant detection, functional validation, biomarker-guided staging, and integration of genomics with imaging and longitudinal modeling to achieve durable and equitable precision ophthalmology. Full article

Sudden cardiac death (SCD) is a major global health issue, defined as sudden natural death presumed to be of cardiac cause. While in the elderly SCD is commonly associated with coronary artery disease, in the younger population it is linked to inherited cardiomyopathies or channelopathies, even though SCD can remain unexplained even after a comprehensive autopsy in a substantial proportion of cases. In this context, genetic testing has gained importance, supported by the widespread availability of techniques such as next-generation and whole-exome/genome sequencing and their reduced costs. This state-of-the-art review summarizes the genetic bases of sudden cardiac death among cardiomyopathies, channelopathies and in sudden unexplained death presumed to be of arrhythmic cause. Among the structural causes, inherited cardiomyopathies such as hypertrophic, dilated, non-dilated left ventricular, arrhythmogenic right ventricular and restrictive ones represent major substrates for malignant ventricular arrhythmias mostly arising from variants in sarcomeric or desmosomal genes. Channelopathies (long or short QT syndrome, Brugada syndrome and catecholaminergic polymorphic ventricular tachycardia) are caused by variants in genes encoding cardiac ion channels and/or regulatory proteins, which equally predispose to high risk of life-threatening ventricular arrhythmias. In sudden arrhythmic death syndrome, with a structurally normal heart, post-mortem genetic testing (molecular autopsy) can uncover an underlying inherited condition. However, variants of uncertain significance are detected in more than half of the cases, underscoring the need for a multidisciplinary approach. Genetic testing also plays a key role in cascade screening of first-degree relatives. While monogenic variants drive risk in inherited cardiac disorders, emerging evidence suggests that polygenic contributions may modulate SCD susceptibility, highlighting future roles for polygenic risk scores in risk stratification. Full article

Hypertrophic cardiomyopathy (HCM), the most common inherited cardiomyopathy, represents a paradigmatic condition for precision cardiovascular medicine. Once regarded as a monogenic autosomal dominant disorder driven by rare sarcomeric variants, HCM is now recognized as a genetically complex disease characterized by incomplete penetrance, variable expressivity, and heterogeneous clinical trajectories. This review summarizes current evidence on the evolving genetic architecture of HCM, emphasizing the predominant role of definitively validated sarcomeric genes, particularly MYBPC3 and MYH7, and the clinical value of gene panel expansion. Phenotypic variability reflects interactions among variant classes, gene-specific mechanisms, and modifying factors. Differences between missense and truncating variants, haploinsufficiency and poison-peptide effects, allelic imbalance, and age-dependent penetrance contribute to diverse disease expression. Emerging data further support oligogenic inheritance and polygenic modulation, with genome-wide association studies and polygenic risk scores elucidating their contribution to disease susceptibility and variability, especially in genotype-negative patients and carriers of rare variants. We also address genes with emerging evidence and underrecognized pathogenic mechanisms, including deep intronic and splice-altering variants that may explain part of the missing heritability. The importance of distinguishing phenocopies is highlighted, advocating for phenotype-anchored diagnostic pathways integrating clinical assessment, multimodality imaging, and targeted genetic testing. Overall, contemporary data support a targeted, gene-validity-driven approach to genetic testing, where molecular findings primarily inform diagnosis and cascade screening, while risk stratification remains phenotype-led and longitudinal. Future progress will depend on integrative models combining rare variants, polygenic background, imaging, and biomarkers to translate genetic complexity into actionable precision care. Full article

Sudden Infant Death Syndrome (SIDS) continues to be one of the most challenging and tragic causes of infant mortality in developed countries. While public health interventions have reduced its prevalence, the underlying mechanisms contributing to SIDS remain largely unclear. The biological basis of SIDS is widely believed to be multifactorial in nature, involving inherited genetic vulnerabilities, including mutations in cardiac ion channels and genes associated with brainstem serotonin function, metabolic enzymes, and inflammatory mediators. This review presents a comprehensive analysis of genetic studies relating to SIDS, incorporating recent findings from molecular autopsies, genome-wide association studies and functional assays. It also explores how gene–environment interactions, polygenic risk scores, and multi-omic strategies are reshaping our understanding of this complex condition. The review aims to integrate recent insights from molecular autopsy, genomic profiling, and gene–environment interactions to offer a framework for better risk assessment and the stratification of vulnerable infants who could benefit from targeted clinical and public health interventions. Full article

Background/Objectives: There is a lack of cohesion in integrating current knowledge on the genetic and environmental etiology of dental impaction. The primary aim of this article is to review the current literature to identify candidate genes involved in the pathogenesis of dental impaction. Methods: A scoping review was conducted following PRISMA-ScR guidelines to identify and organize the available body of evidence. Relevant literature was searched in MEDLINE (via PubMed), Scopus, and Web of Science, with the final search conducted on 03 January 2026. Eligibility criteria included case–control, cohort, cross-sectional observational, and case report studies in humans. Selected studies focused on syndromic and non-syndromic variants, inheritance patterns, and genetic analyses. Risk of bias was assessed using the Joanna Briggs Institute (JBI) Critical Appraisal Checklists and AMSTAR 2. Results: Only 18 studies met the eligibility criteria. Most articles were case reports and retrospective observational studies, revealing a multifaceted genetic landscape underlying dental impaction, with mutations affecting transcription factors and signaling pathways critical for odontogenesis, particularly RUNX2, FGFR1, MSX1, PAX9, and AXIN2. Overall, the included studies showed moderate methodological quality. Conclusions: Current evidence does not clearly support specific genes as causal factors in dental impaction, but instead suggests a complex, likely polygenic susceptibility that modulates the anatomical threshold for tooth eruption. This review highlights RUNX2, FGFR1, MSX1, PAX9, and AXIN2, as well as emerging candidates involved in eruption and bone remodeling pathways. Future progress depends on standardized phenotyping, large replicated cohorts, and functional studies linking genetic variation to dental follicle-mediated eruptive remodeling. Full article

Myopia is a prevalent ocular condition with marked heterogeneity in onset and progression. Although diagnosis is straightforward, predicting disease trajectories and identifying risks of high or pathologic myopia remain main clinical challenges. Advances in human genetics have substantially reshaped current understanding of myopia, revealing a complex architecture involving common polygenic susceptibility, rare high-impact variants, and cumulative genetic risk burden. Large-scale genome-wide association studies demonstrate that myopia-related variants are enriched in regulatory and signaling pathways that modulate retinal neuronal and glial responses to visual and metabolic stimuli, while exome sequencing studies highlight overlap between early-onset high myopia and inherited retinal or syndromic disorders. Polygenic risk scores further translate common-variant burden into quantitative measures of genetic susceptibility, enabling population-level risk stratification and early risk assessment, albeit with performance differences across ancestries and clinical outcomes. Together, these findings delineate a multilayered genetic framework for myopia and support the role of genetic information as a complementary component of prognostic assessment. Integration of genetic data with longitudinal clinical and environmental information may further improve the prediction of myopia trajectories and facilitate more individualized management strategies. Full article

Background: Diabetes mellitus is characterized by elevated blood sugar due to absolute or relative insulin deficiency. Diabetes is classified as type 1 (T1D) or type 2 diabetes (T2D), gestational diabetes, and other types, such as monogenic diabetes, exocrine pancreatic disorders, and medication-induced diabetes. Objectives: This review article provides an overview of diabetes genetics, covering polygenic, monogenic, and syndromic forms of the disorder with emphasis on aspects to help clinicians in diagnosis, management, and counseling, but also to foster valuable knowledge for diabetic researchers in identifying phenotypes that will help inform gene discovery. Key Findings: Most cases of T1D and T2D are polygenic with environmental triggers. T1D results from autoimmune destruction of pancreatic beta cells leading to absolute insulin deficiency. Genetic studies of T1D have focused on the identification of loci associated with increased susceptibility to T1D. Early studies showed a linkage between T1D and several human leukocyte antigen (HLA) susceptibility loci on chromosome 6. Genome-wide association studies (GWAS) have identified more than 100 HLA- and non-HLA loci that increase susceptibility to T1D. It has been well established that a substantial portion of the genetic risk for T1D is encoded in the HLA locus. The non-HLA loci INS, CTLA4, IL2RA, IFIH1, and PTPN22 make moderate contributions to T1D risk. Many other non-HLA loci have small effects to the phenotype and are relevant to autoimmunity, but they are yet to be identified. T2D, on the other hand, is associated with obesity and insulin resistance with relative insulin deficiency. Thousands of gene variants that are common and contribute small effects have also been identified through GWAS to contribute to T2D risk, but the rarer variants may confer significant risk to an individual’s risk. Common variants in the TCF7L2 locus consistently carry one of the largest risks associated with T2D with a reported 1.7-fold disease odds for homozygous carriers. The usefulness of individual variants for genetic counseling in the common forms of diabetes has been limited in clinical settings in the past. The development of polygenic risk scores (PRS) and partitioned polygenic risk scores (PPRS), statistics derived from GWAS, are being used to predict and classify diabetes. The performance of PRS and PPRS varies by ancestry and type of diabetes. The PRS performs better with T1D, with an area under the curve and receiver operating characteristics (AUC-ROC) ranging from 0.87 to 0.93, compared to 0.72–0.75 for T2D. The genetic architecture of T2D is markedly more polygenic than T1D, and the PPRS has been useful in assessing risk in that setting. Monogenic diabetes comprises several dysglycemic disorders that include neonatal diabetes, maturity-onset diabetes of the young (MODY), and other genetic syndromes that have diabetes either as an associated finding and/or as a complication. Some of the monogenic diabetes gene variants have incomplete penetrance and variable expressivity leading to different ages of onset and variable presentation even within the same family. Hence some patients with these conditions have been previously diagnosed as having T1D or T2D. Many monogenic disorders follow Mendelian inheritance patterns, so genetic counseling is relatively straightforward if pathogenic variants are found to be inherited from a parent. Counseling for forms of diabetes due to maternally inherited mitochondrial cytopathies, such as MELAS and Kearns–Sayres syndrome, is not straightforward due to the occurrence of two or more populations of genetically distinct mitochondrial DNAs in the cells (heteroplasmy); the higher the percent of pathogenic variants in a cell or tissue, the greater the chance for affectation of disorder. Implications: Early stages of diabetes may be asymptomatic, and improvement in methodologies to identify individuals at high risk is important so prevention strategies can be targeted to susceptible individuals to slow or obviate the onset of disease and to minimize complications. Conclusions: Diabetes is a heterogeneous disorder, and accurate definition of phenotypes in the setting of non-syndromic and syndromic forms, development of powerful statistical methodologies, use of next-generation sequencing applications to interrogate the genome, incorporation of epigenetic mechanisms in statistical modeling and accurate curation of gene variants, will help us to realize application of genomic medicine and to inform diabetes care. Full article

Androgenetic alopecia (AGA) is the most common cause of progressive hair thinning in adults and has traditionally been viewed as an androgen-driven inherited condition. Genomic research now demonstrates that AGA is a complex polygenic disorder involving multiple biological pathways, including androgen signaling, hair follicle development, cell survival, and extracellular matrix remodeling. Genome-wide association studies have identified numerous susceptibility loci, revealing that follicle miniaturization arises from interacting molecular mechanisms rather than a single pathogenic process. Genetic risk and predictive value vary across populations, with many loci identified in European cohorts showing limited transferability to other ancestries, highlighting the need for more diverse genetic studies. In women, genetic studies remain underpowered, and emerging data suggest partially distinct risk architecture compared with male AGA. Pharmacogenetic findings indicate that genetic variation may influence response to commonly used therapies, although no markers are currently validated for routine clinical use. Advances in single-cell and multi-omic approaches are improving understanding of how genetic risk translates into follicular dysfunction, supporting the development of more personalized and mechanism-based treatment strategies. Full article

Background: Iron-refractory iron deficiency anemia (IRIDA) is a rare hereditary disorder caused by pathogenic variants in TMPRSS6, characterized by microcytic anemia, low circulating iron levels, and inappropriately high hepcidin levels. Although IRIDA is typically an autosomal recessive disorder, some individuals with a monoallelic pathogenic exonic TMPRSS6 variant exhibit the phenotype, suggesting additional contributing factors. The mechanisms underlying monoallelic IRIDA remain unclear, complicating diagnosis. This study aimed to investigate the potential role of non-coding TMPRSS6 variants and polygenic inheritance in monoallelic IRIDA. Methods: We performed full-gene sequencing of TMPRSS6 in a cohort of 27 subjects, including 6 families (7 symptomatic monoallelic, 7 asymptomatic monoallelic, and 4 wild-type subjects) and 9 isolated symptomatic monoallelic subjects. Whole-exome sequencing of other iron-regulating genes was conducted to evaluate polygenic inheritance. Non-coding variants were assessed for inheritance patterns using family segregation analysis, when available, and for pathogenic potential using in silico prediction tools. Results: Sequencing identified 219 non-coding variants, of which 31 (14 trans-inherited and 17 with unknown inheritance) were exclusive to symptomatic subjects. Two trans-inherited variants (rs80140288 (c.229+945C>T) and rs146953827 (c.230-938_230-937del)) were predicted to affect splicing, while two additional variants (rs78987624 (c.-7001G>A) and rs117575523 (c.*503C>G)) were located in regulatory regions (with unknown inheritance). Whole-exome sequencing did not support polygenic involving other iron-regulating genes. Conclusions: This study highlights four candidate non-coding variants that may contribute to IRIDA expression in monoallelic subjects, offering new insights into its genetic basis. Functional validation is required to confirm their role in disease pathogenesis, refine genotype-phenotype correlations, and improve diagnostic accuracy in monoallelic IRIDA. Full article

Background: Keratoconus (KC) is a progressive corneal ectasia and a leading cause of corneal transplantation in young adults. Once regarded as a biomechanical disorder, KC is now recognized as a complex disease driven by genetic predisposition, epigenetic modulation, and environmental triggers. Advances in genomics and transcriptomics have begun to elucidate the molecular mechanisms underlying corneal thinning and ectasia. Objectives: This review synthesizes two decades of evidence on the genetic and epigenetic architecture of keratoconus, highlights key molecular pathways implicated by these findings, and discusses translational implications for early diagnosis, risk prediction, and novel therapeutic strategies. Methods: A narrative review was conducted of peer-reviewed human, animal, and in vitro studies published from 2000 to 2025, with emphasis on genome-wide association studies (GWAS), sequencing data, methylation profiling, and non-coding RNA analyses. Findings were integrated with functional studies linking genetic variation to molecular and biomechanical phenotypes. Results: Genetic studies consistently implicate loci such as ZNF469, COL5A1, LOX, HGF, FOXO1, and WNT10A, alongside rare variants in Mendelian syndromes (e.g., brittle cornea syndrome, Ehlers–Danlos spectrum). Epigenetic research demonstrates altered DNA methylation, dysregulated microRNAs (e.g., MIR184, miR-143, miR-182), and aberrant lncRNA networks influencing extracellular matrix remodeling, collagen cross-linking, oxidative stress, and inflammatory signaling. Gene–environment interactions, particularly with eye rubbing and atopy, further shape disease expression. Translational progress includes polygenic risk scores, tear-based biomarkers, and early preclinical studies using RNA-based approaches (including siRNA and antisense oligonucleotides targeting matrix-degrading and profibrotic pathways) and proof-of-concept gene-editing strategies demonstrated in corneal cell and ex vivo models. Conclusions: Keratoconus arises from the convergence of inherited genomic risk, epigenetic dysregulation, and environmental stressors. Integrating multi-omic insights into clinical practice holds promise for earlier detection, precision risk stratification, and development of targeted therapies that move beyond biomechanical stabilization to disease modification. Full article

Inherited arrhythmias and cardiomyopathies are a group of potentially lethal genetic cardiac disorders which are often passed down through generations and pose risks to several family members. While individually rare, these conditions are collectively common and pose significant challenges for clinical management given their variable severity, age of onset, and response to treatments. Earlier genetic analyses revealed crucial insights into the main genetic culprits of these disorders, such as SCN5A for Brugada syndrome, and MYH7 and MYBPC3 for hypertrophic cardiomyopathy, which have revolutionized diagnosis, risk stratification, and medical management. Nonetheless, issues such as variable expressivity and penetrance, low yield of genetic testing, and relative lack of disease-modifying therapies remain significant hurdles for clinical management. The revolution of genome-wide association studies GWASs has transformed our understanding of inherited arrhythmias and cardiomyopathies, shifting the view of these disorders from a monogenic Mendelian inheritance towards a more complex, often polygenic inheritance with nuanced interplay between genetics and environment. Moreover, GWASs have enabled the quantification of polygenic predisposition to disease using polygenic risk scores, which are often complementary to and independent of monogenic risk. In this review, we highlight how GWASs have transformed the field of inherited arrhythmias and cardiomyopathies, with a particular focus on the polygenic risk scores developed and their clinical utility for the four disorders which have been impacted by GWASs—hypertrophic cardiomyopathy, dilated cardiomyopathy, Brugada syndrome, and long QT syndrome. Full article

Myxomatous mitral valve disease (MMVD) is the most prevalent cardiac disorder in small and toy breed dogs, with the Cavalier King Charles Spaniel (CKCS) showing exceptionally high predisposition and early onset of the disease. MMVD is characterized by progressive mitral valve degeneration, volume overload, and eventual development of congestive heart failure (CHF). Given the strong hereditary component in CKCS, considerable research has focused on elucidating the genetic basis of MMVD in this breed. This review article summarizes the current state of knowledge on the phenotypic features, inheritance, and candidate loci potentially responsible for early onset and severe course of the disease. The pathogenesis of the disease, its classification, and the effects of breeding programs aimed at reducing the occurrence of MMVD have been described. Key findings include associations between MMVD severity and polymorphisms in genes such as NEBL, ACE, CDK6, HEPACAM2, COL5A1, and FAH, as well as evidence implicating dysregulated TGF-β signaling, serotonin signaling, and extracellular matrix remodeling pathways. The current state of knowledge on the role of miRNA in the pathogenesis of MMVD was also summarized. Despite these findings, no specific high-penetrating mutation has been identified. MMVD is a complex, polygenic condition shaped by regulatory variants and breed-specific genetic bottlenecks. Comparative studies underscore the translational relevance of canine MMVD to human mitral valve disease, while genomic insights may be basis for the future selective breeding strategies and therapeutic approaches. Further large-scale, integrative studies combining genomics, transcriptomics, and functional validation are needed to clarify disease mechanisms and support targeted treatment in CKCS as well as the development of new breeding strategies and programs. Full article

Plumage coloration in ducks (Anas platyrhynchos) represents a complex polygenic trait of significant economic and biological importance in commercial poultry production. This comprehensive review synthesizes current knowledge on the genetic mechanisms underlying feather coloration in domestic ducks, with particular emphasis on melanin biosynthesis pathways and their regulatory networks. We systematically analyzed recent advances including genome-wide association studies, RNA sequencing, whole-genome resequencing, and population genetics approaches that have identified key candidate genes controlling duck pigmentation patterns. The melanogenesis pathway emerges as the central regulatory network, with nine core genes (MITF, MC1R, TYR, TYRP1, DCT, SOX10, KIT, EDNRB2, and MLANA) consistently associated with plumage coloration across multiple duck populations. The MITF functions as the master regulator, coordinating expression of the enzymatic triad (TYR, TYRP1, DCT) responsible for melanin synthesis, while MC1R serves as the primary receptor controlling eumelanin versus pheomelanin production ratios. Epistatic interactions between MITF and MC1R demonstrate the complexity of color inheritance, with MITF exhibiting dominant effects over MC1R in determining white versus black plumage phenotypes. Functional enrichment analyses confirm these genes’ central roles in melanin biosynthetic processes and tyrosine metabolism pathways. Additionally, recent studies have revealed the importance of regulatory mechanisms, including epigenetic modifications and tissue-specific expression patterns, in modulating final coloration phenotypes. Understanding these genetic determinants provides valuable insights for selective breeding programs aimed at optimizing esthetic and economic traits in duck production. This review establishes a foundation for future research in avian pigmentation genetics and offers practical applications for improving breeding efficiency and product quality in the global duck industry. Full article

Understanding the genetic architecture of complex traits is crucial for crop improvement and molecular breeding. We developed a mutagenized soybean population using carbon ion beam irradiation and conducted genome-wide association studies (GWAS) to identify variants controlling key agronomic traits. Whole-genome resequencing of 199 M4 lines revealed 1.48 million SNPs, predominantly C→T transitions, with population structure analysis identifying three distinct genetic groups. GWAS across five traits revealed striking differences in genetic architecture: the podding habit showed extreme polygenic control with 87,029 significant associations of small effect, while pubescence color exhibited oligogenic inheritance with only 122 variants. Hundred-seed weight displayed moderate complexity (4637 associations) with the largest effect sizes (−3.74 to 5.03) and major QTLs on chromosomes 4, 7, and 15–20. Growth habit involved 12,136 SNPs, including a strong chromosome 3 association (−log₁₀(p-value) > 50). Flower color showed 2662 associations clustered on chromosome 15. Functional analysis of 18,542 candidate genes revealed trait-specific pathway enrichments: flavonoid biosynthesis for flower color, phloem transport for seed weight, auxin signaling for growth habit, and amino acid transport for podding habit. This study demonstrates how mutagenesis-induced variation, combined with association mapping, reveals evolutionary constraints that shape genetic architectures, providing insights for genetics-assisted breeding strategies. Full article

Background: Autism spectrum disorder (ASD) is a common condition with substantial personal and financial burdens of lifelong implication. Multiple twin studies have confirmed a genetic or inherited component at ~80%, higher than any other common condition. However, ASD’s rapidly accelerating prevalence, now at 1 in 31 in the USA, appears to defy a predominantly genetic basis and implicate our rapidly changing environment. A potential explanation for this paradox is a recent increase in de novo variants (DNVs), which are “new” mutations present in the patient yet absent in both parents. The present authors recently reported using trio whole-genome sequencing (trio-WGS) that DNVs highly likely to be highly disease-associated (“Principal Diagnostic Variants”, PDVs), mostly missense variants, were present in (25/50) 50% of the ASD patients clinically evaluated by our team. Methods: The current study was designed to support this observation with trio-WGS in 100 additional unrelated ASD patients. Results: De novo PDVs were identified in 47/100 (47%) of cases, in close approximation to our previous work. Using non-transcribed (up and downstream) variants for all genes as a control group, these DNV-PDVs were far more likely (p < 0.0001, OR 5.8, 95% C.I. 2.9–11) to be in SFARI-listed genes associated with ASD. Consistent with the emerging polygenic model, using the same analyses, inherited missense variants were also associated with ASD (p < 0.0001). Highly unexpectedly, silent variants, both inherited (p < 0.0001) and de novo (p < 0.007), were also statistically associated with ASD, and, among inherited variants, silent variants were more associated with ASD than were missense variants (p < 0.0001). Adding silent DNVs as PDVs increases the proportion of our subjects with at least one DNV-PDV to 55% of the subjects. Conclusions: Our proposed model for ASD, with prominent DNVs in most that are genetic yet not inherited, predicts the known predominant genetic pathogenesis and the accelerating prevalence of ASD, possibly from environmental factors, including insufficient nutrients and toxicant exposures, and/or the disrupted folate metabolism known to be associated with ASD. Limitations to this study include predominant inclusion of severely affected individuals and the lack of an unaffected control group and functional validation of variant pathogenicity. Full article