Search Results (234)

Neurodevelopmental disorders (NDDs) represent a heterogeneous group of diseases with a variety of clinical presentations related to different genetic, epigenetic, and environmental etiologies. Numerous pathogenic variants have been identified by comprehensive genetic approaches such as next-generation sequencing and chromosomal microarray analyses. This study included eleven pediatric patients with NDDs who were referred to our Molecular Medicine (MM) unit for further diagnostic workup. Whole exome sequencing (WES) was performed, and data were analyzed as part of a contracted service with the National Genomic Center and iBioScience LTD. Likely pathogenic single nucleotide variants in genes DDX3X c.869C>A, p.S290* and CNOT1 c.920delG, p.G307Afs*32 in two patients, and pathogenic copy number variants in the 16p11.2 (16:29,690,418-30,200,285)x3 and 16p12.1-p11.2 (16:27,078,317-29,001,333)x3 regions in a third patient with NDDs were identified. In a fourth patient, the c.6839A>G, p.Gln2280Arg variant of uncertain significance was found in the NIPBL gene. Altogether, our study has revealed four novel variants in genes previously linked to NDDs. Identification of genetic causes of NDDs not only promotes establishing a more precise diagnosis and improves our understanding of disease pathogenesis but may also provide better means for developing preventive measures for the recurrence of this serious condition. Full article

Background: Dominantly acting variants in TUBB2B have primarily been associated with cortical dysplasia complex with other brain malformations 7 (CDCBM7), a disorder in which cortical brain abnormalities are typically linked to developmental delay/intellectual disability (DD/ID) and seizures. While the majority of TUBB2B pathogenic variants have been linked to isolated CDCBM7, only one family with CDCBM7 and congenital fibrosis of the extraocular muscles (CFEOM) has been reported so far. We describe a second individual with a severe phenotype of CFEOM combined with CDCBM7 carrying a pathogenic TUBB2B missense variant previously reported in two individuals with isolated CDCBM7. Methods: A trio-based WGS analysis was performed. The structural impact of the identified substitution was assessed by using the UCSF Chimera (v.1.17.3) software and PyMOL docking plugin DockingPie tool. Results: WGS analysis identified a de novo missense TUBB2B variant (p.Ile202Thr, NM_178012.5), previously associated with isolated CDCBM7. Structural analysis and docking simulations revealed that Ile202 contributes to establishing a proper hydrophobic environment required to stabilize GTP/GDP in the β-tubulin pocket. p.Ile202Thr was predicted to disrupt these interactions. Conclusions: Our findings broaden the mutational spectrum of TUBB2B-related CFEOM, targeting a different functional domain of the protein, and further document the occurrence of phenotypic heterogeneity. We also highlight the limitations of exome sequencing in accurately mapping TUBB2B coding exons due to its high sequence homology with TUBB2A and suggest targeted or genome analyses when clinical suspicion is strong. Full article

Mitochondrial network dynamics, encompassing processes like fission, fusion, and mitophagy, are crucial for mitochondrial function and overall cellular health. Dysregulation of these processes has been linked to various human diseases. Particularly, pathogenic variants in the gene DNM1L can lead to a broad range of clinical phenotypes, ranging from isolated optic atrophy to severe neurological conditions. DNM1L encodes DRP1 (dynamin-1-like protein), which is a key player in mitochondrial and peroxisomal fission. This study describes two twin sisters with a de novo heterozygous variant in DNM1L, due to possible paternal germline mosaicism identified through clinical exome sequencing. The two twins showed a variable clinical presentation, including paraparesis and optic neuropathy. Functional studies of patient-derived fibroblasts revealed altered mitochondrial and peroxisomal morphology, along with dysregulated DNM1L transcript levels, indicating the deleterious effect of the variant. These findings allowed us to reclassify the identified variant from a variant of uncertain significance to a likely pathogenic variant. Our report provides insight into the phenotypic spectrum of DNM1L-related disorders and highlights the need to combine genetic and functional analyses to accurately diagnose rare mitochondrial diseases. Full article

Osteoporosis is a common disease characterized by a reduction in bone mineral density (BMD), leading to an increased risk of pathological fractures and even mortality. Although menopause is a major risk factor, osteoporosis can also occur in premenopausal women. The aim of this study was to identify genetic variants associated with the development of osteoporosis in Korean premenopausal women. Subjects were recruited from the Anseong and Ansan cohorts of the Korean Genome and Epidemiology Study (KoGES). Clinical and epidemiological characteristics were assessed, and participants were classified based on BMD values measured at the distal radius and mid-shaft tibia. Individuals with confounding risk factors such as low body weight, smoking, high alcohol consumption, steroid/hormone therapy, or relevant medical history were excluded. A total of 247 healthy controls and 57 osteoporosis patients were included. Genotyping was performed using the Illumina Infinium HumanExome BeadChip and the Affymetrix Axiom Exome Array. Data were analyzed using the SNP and Variation Suite and PLINK, with quality control thresholds set at MAF ≥ 0.05 and HWE p ≥ 0.01. Functional annotation and protein structure predictions were performed using PolyPhen-2, SIFT, and PROVEAN. Genome-wide association analyses identified 113 single-nucleotide polymorphisms (SNPs) in 69 genes significantly associated with osteoporosis (p < 0.05) in both platforms, with 18 SNPs showing high cross-platform consistency (p < 0.01). Several of these genes were implicated in bone metabolism (e.g., ESRRG, PECAM1, COL6A5), vitamin D metabolism (e.g., NADSYN1, EFTUD1), skeletal muscle function (e.g., PACSIN2, ESRRG), and reproductive processes (e.g., CPEB1, EFCAB6, ASXL3). Notably, the CPEB1 rs783540 SNP exhibited the strongest association (p < 0.001) in both analyses. Our findings suggest that genetic polymorphisms in pathways related to bone metabolism, vitamin D signaling, muscle–bone interaction, and reproductive hormone regulation may contribute to the development of osteoporosis in Korean premenopausal women. These results provide a genetic basis for early identification of at-risk individuals and warrant further functional studies to elucidate the underlying mechanisms. Full article

Zinc finger proteins are frequently implicated in a wide range of neurodevelopmental disorders (NDDs). In this study, we report a case of mild intellectual disability (ID), global developmental delay (GDD), and developmental coordination disorder (DCD) in an individual with unaffected parents. Trio-based whole-exome sequencing (WES) identified a de novo variant (c.1530dup, p.Glu511ArgfsTer16) in the ZNF496 gene of the proband. According to ACMG guidelines, this novel variant is classified as pathogenic. It creates a frameshift that introduces a premature stop codon, resulting in a truncated protein of 525 amino acids (compared to the wild-type 587 residues). Notably, NMDEscPredictor analysis predicted that the transcript escapes nonsense-mediated decay (NMD) despite the frameshift. Computational analyses suggest the potential pathogenetic effects of the identified variant. As documented, ZNF496 interacts with JARID2, a gene associated with NDDs, ID and facial dysmorphism (MIM: #620098). In silico analyses suggest that the identified mutation disrupts this interaction by deleting ZNF496’s C2H2 domain, potentially dysregulating JARID2 target genes. To our knowledge, this is the first reported association between ZNF496 and NDDs, and the variant has been submitted to the ClinVar database (SCV006100880). Functional studies are imperative to validate ZNF496’s role in NDDs and confirm the mutation’s impact on ZNF496-JARID2 interactions. Full article

Background: Charcot–Marie–Tooth disease (CMT) is a genetically and phenotypically heterogeneous hereditary neuropathy. Axonal CMT type 2 (CMT2) subtypes often exhibit overlapping clinical features, which makes molecular genetic analysis essential for accurate diagnosis and subtype differentiation. Methods: This retrospective study included five pediatric patients who presented with gait disturbance, muscle weakness, and foot deformities and were subsequently diagnosed with axonal forms of CMT. Clinical data, electrophysiological studies, neuroimaging, and genetic analyses were evaluated. Whole exome sequencing (WES) was performed in three sporadic cases, while targeted CMT gene panel testing was used for two siblings. Variants were interpreted using ACMG guidelines, supported by public databases (ClinVar, HGMD, and VarSome), and confirmed by Sanger sequencing when available. Results: All had absent deep tendon reflexes and distal muscle weakness; three had intellectual disability. One patient was found to carry a novel homozygous frameshift variant (c.2568_2569del) in the IGHMBP2 gene, consistent with CMT2S. Other variants were identified in the NEFH (CMT2CC), DYNC1H1 (CMT2O), and MPV17 (CMT2EE) genes. Notably, a previously unreported co-occurrence of MPV17 mutation and congenital heart disease was observed in one case. Conclusions: This study expands the clinical and genetic spectrum of pediatric axonal CMT and highlights the role of early physical examination and molecular diagnostics in detecting rare variants. Identification of a novel IGHMBP2 variant and unique phenotypic associations provides new insights for future genotype–phenotype correlation studies. Full article

Familial dysbetalipoproteinemia (FD) is a prevalent and highly atherogenic hyperlipoproteinemia associated with the ε2/ε2 APOE genotype or rare APOE variants. The contributions of additional genetic and clinical factors to the FD phenotype remain unclear. We investigated these factors in both autosomal recessive and autosomal dominant forms of FD. Targeted (n = 4666) and exome (n = 194) sequencing were used to identify the ε2/ε2 APOE genotype or rare FD-causative APOE variants. Twenty-four lipid-related genes and forty variants included in a polygenic risk score for hypertriglyceridemia (HTG) were analyzed. FD was defined by the presence of FD variants and triglycerides (TG) ≥ 1.5 mmol/L (main study group). The comparison group consisted of patients with FD variants but TG < 1.5 mmol/L. Univariable and multivariable regression analyses were performed. A total of 71 unrelated subjects were identified (45.1% male, median age 50 years). FD was diagnosed in 52 patients, while 19 had FD variants only. Age (p = 0.019), elevated polygenic risk for HTG (p = 0.001), and the presence of metabolic syndrome components (p = 0.014) were independently associated with the FD phenotype. TG levels were significantly associated with polygenic burden (0.05 mmol/L per percentile), the presence of additional rare lipid-related variants (7.0 mmol/L), and glucose metabolism disorders (3.62 mmol/L), together explaining 30% of TG variance in cross-validated model. These results highlight the interplay of genetic and metabolic factors in FD development and support the integration of HTG genetic risk scores and metabolic control into personalized FD management. Full article

Pathogenic variants in the MAP1B gene have been associated with neurological impairment, including intellectual disability, attention-deficit/hyperactivity disorder (ADHD), autism spectrum disorder, brain malformations, cognitive hearing loss, short stature, and dysmorphic features. However, few cases with detailed clinical characterization have been reported. We describe a 12-year-old boy carrying a loss-of-function MAP1B variant, presenting with severe elimination disorders despite normal intelligence. He was referred to the genetics service due to persistent elimination issues, including daytime urinary incontinence, nocturnal enuresis, and fecal incontinence. He had normal motor and cognitive development, with an IQ of 99; however, he also presented with ADHD, short stature, microcephaly, and myopia. Brain MRI revealed bilaterial subependymal periventricular nodular heterotopia (PVNH). Audiometry showed normal bilateral hearing. Testing fragile X syndrome (FXS) and karyotype analyses yielded normal results. Whole exome sequencing (WES) revealed a nonsense pathogenic variant in MAP1B (c.895 C>T; p.Arg299*). No other family members showed a similar phenotype; however, a great-uncle and a great-aunt had a history of nocturnal enuresis until age 10. The patient’s deceased mother had short stature and psychiatric disorders, and a history of consanguinity was reported on the maternal side. This case broadens the phenotypic spectrum associated with MAP1B syndrome, suggesting that elimination disorder, frequently reported in FXS, should also be evaluated in MAP1B pathogenic variant carriers. In addition, the presence of short stature also appears to be part of the syndrome. Full article

Precision medicine is transforming hematologic cancer care by tailoring treatments to individual patient profiles and moving beyond the traditional “one-size-fits-all” model. This review outlines foundational technologies, disease-specific advances, and emerging directions in precision hematology. The field is enabled by molecular profiling techniques, including next-generation sequencing (NGS), whole-exome sequencing (WES), and RNA sequencing (RNA-seq), as well as epigenomic and proteomic analyses. Complementary tools such as liquid biopsy and minimal residual disease (MRD) monitoring have improved diagnosis, risk stratification, and therapeutic decision making. We discuss major molecular targets and personalized strategies across hematologic malignancies: FLT3 and IDH1/2 in acute myeloid leukemia (AML); Philadelphia chromosome–positive and Ph-like subtypes in acute lymphoblastic leukemia (ALL); BCR-ABL1 in chronic myeloid leukemia (CML); TP53 and IGHV mutations in chronic lymphocytic leukemia (CLL); molecular subtypes and immune targets in diffuse large B-cell lymphoma (DLBCL) and other lymphomas; and B-cell maturation antigen (BCMA) in multiple myeloma. Despite significant progress, challenges remain, including high costs, disparities in access, a lack of standardization, and integration barriers in clinical practice. However, advances in single-cell sequencing, spatial transcriptomics, drug repurposing, immunotherapies, pan-cancer trials, precision prevention, and AI-guided algorithms offer promising avenues to refine treatment and improve outcomes. Overcoming these barriers will be critical for ensuring the equitable and widespread implementation of precision medicine in routine hematologic oncology care. Full article

Background/Objectives: Neurodevelopmental disorders (NDDs) represent a clinically diverse group of conditions that affect brain development, often leading to varying degrees of functional impairment. Many NDDs, particularly syndromic forms, are caused by genetic mutations affecting critical cellular pathways. Ribosomopathies, a subgroup of NDDs, are linked to defects in ribosomal function, including those involving the synthesis of diphthamide, a post-translational modification of translation elongation factor 2 (eEF2). Loss-of-function (LoF) mutations in genes involved in diphthamide biosynthesis, such as DPH1, DPH2, and DPH5, result in developmental delay (DD), intellectual disability (ID), and multisystemic abnormalities. DPH5-related diphthamide deficiency syndrome has recently been reported as an ultrarare disorder linked to LoF mutations in DPH5, encoding a methyltransferase required for diphthamide synthesis. Methods: Clinical, neurological, and dysmorphological evaluations were performed by a multidisciplinary team. Brain MRI was acquired on a 3T scanner. Craniofacial abnormalities were assessed using the GestaltMatcher phenotyping tool. Whole exome sequencing (WES) was conducted on leukocyte-derived DNA with a trio-based approach. Bioinformatic analyses included variant annotation, filtering, and pathogenicity prediction using established databases and tools. Results: The affected subject carried a previously reported missense change, p.His260Arg, suggesting the occurrence of genotype–phenotype correlations and a hypomorphic behavior of the variant, likely explaining the overall milder phenotype compared to the previously reported patients with DPH5-related diphthamide deficiency syndrome. Conclusions: Overall, the co-occurrence of short stature, relative macrocephaly, congenital heart defects, variable DD/ID, minor skeletal and ectodermal features, and consistent craniofacial features suggests a differential diagnosis with Noonan syndrome and related phenotypes. Full article

Background: Developmental delay and intellectual disability (DD/ID) are frequently accompanied by epilepsy, and growing evidence implicates variants in voltage-gated calcium channel genes in their pathogenesis. This study aimed to investigate the association of polymorphisms in CACNA1A, CACNA1C, and CACNA1H with DD/ID and epilepsy comorbidity in Korean children. Methods: We retrospectively analyzed 141 pediatric patients diagnosed with DD/ID who underwent whole-exome sequencing (WES) and were not found to have pathogenic monogenic variants. Nine single-nucleotide polymorphisms (SNPs) across CACNA1A, CACNA1C, and CACNA1H were selected based on functional annotation scores and prior literature. Genotype data were extracted from WES variant files, and allele and genotype frequencies were compared with control data from the gnomAD East Asian population and the Korean Reference Genome Database (KRGDB). Subgroup analyses were performed according to epilepsy comorbidity. Results: The CACNA1A rs16023 variant showed a significantly higher B allele frequency in DD/ID patients than in both control datasets and was also associated with epilepsy comorbidity. Genotype distribution analysis revealed that the BB genotype of rs16023 was more frequent in patients with epilepsy. Conclusions: The CACNA1A rs16023 variant may contribute to genetic susceptibility to DD/ID and epilepsy in Korean children, potentially through regulatory mechanisms. These findings support the relevance of calcium channel genes in neurodevelopmental disorders and highlight the importance of integrating functional annotation in variant prioritization. Full article

Autism spectrum disorder (ASD) is a neurodevelopmental impairment that occurs due to mutations related to the formation of the nervous system, combined with the impact of various epigenetic and environmental factors. This necessitates the identification of the genetic variations involved in ASD pathogenesis. We performed whole exome sequencing (WES) in a cohort of 22 Bulgarian male and female individuals showing ASD features alongside segregation analyses of their families. A targeted panel of genes was chosen and analyzed for each case, based on a detailed examination of clinical data. Gene analyses revealed that specific variants concern key neurobiological processes involving neuronal architecture, development, and function. These variants occur in a number of genes, including SHANK3, DLG3, NALCN, and PACS2 which are critical for synaptic signaling imbalance, CEP120 and BBS5 for ciliopathies, SPTAN1 for spectrins structure, SPATA5, TRAK1, and VPS13B for neuronal organelles trafficking and integrity, TAF6, SMARCB1, DDX3X, MECP2, and SETD1A for gene expression, CDK13 for cell cycle control, ALDH5A1, DPYD, FH, and PDHX for mitochondrial function, and PQBP1, HUWE1, and WDR45 for neuron homeostasis. Novel single nucleotide variants in the SPATA5, CEP120, BBS5, SETD1A, TRAK1, VPS13B, and DDX3X genes have been identified and proposed for use in ASD diagnostics. Our data contribute to a better understanding of the complex neurobiological features of autism and are applicable in the diagnosis and development of personalized therapeutic approaches. Full article

Dysregulated expression of nuclear receptor superfamily 4 group A member 2 (NR4A2) has recently been associated with autistic spectrum disorder (ASD), speech impairment, and neurodevelopmental delay (NDD); however, its precise role in the prevalence and etiopathogenesis of ASD has not been fully elucidated. Herein, we aimed to explore the role of NR4A2 variants in the genetic underpinnings of ASD among Saudi children of different age ranges and phenotype severities. A total of 338 children with ASD from 315 unrelated families (293 simplex, 2 quads, and 1 quintet) were screened for NR4A2 variants via exome sequencing (ES) of the genomic DNA extracted from peripheral blood mononuclear cells (PBMCs), after which the probands with identified NR4A2 variants were further subjected to trio genetic analyses. ES analysis revealed 10 de novo NR4A2 variants (5 indels/nonsense, 2 missense, and 3 variants affecting splicing) in 8 unrelated probands (2.37%) and 2 affected siblings from 8 unrelated families (6 simplex (2.04%) and 2 quads (8.7%)). Three NR4A2 variants were notably recurrent among both affected and unaffected carriers. All identified indels and two splicing variants met the criteria for pathogenic/loss-of-function (LoF) variants according to the ACMG classification (PVS1), whereas the missense variants were classified as of uncertain significance (VUS). This study is among the first to identify such a high frequency of recurrent variants in an ASD cohort, suggesting their significant contribution to the etiopathogenesis of ASD within this population. Full article

Atypical fibroxanthoma (AFX) and pleomorphic dermal sarcoma (PDS) are dermal-based sarcomas that fall along a spectrum with different rates of local recurrence and metastasis. While AFX is less aggressive and confined to the dermis, PDS invades the subcutis. These tumors are most likely of mesenchymal origin, although they share common mutations with undifferentiated squamous cell carcinoma. Due to the rarity of these tumors, few studies have examined their molecular composition and gene expression. Initial studies, including exome and bulk RNA sequencing, targeted DNA sequencing of gene panels, DNA methylation, and copy number analyses, have identified recurrent UV-induced mutations in TP53, NOTCH, CDKN2A, and the TERT promoter. Recently, the first scRNA-seq dataset in AFX and PDS identified COL6A3 as a novel biomarker. In this review, we synthesize the above datasets and discuss our current understanding of the molecular drivers and prognostic biomarkers in these tumors. Full article

Friedreich’s ataxia (FRDA) is an autosomal recessive neurodegenerative disorder characterized by ataxia, sensory loss and pyramidal signs. While the majority of FRDA cases are caused by biallelic GAA trinucleotide repeat expansions in intron 1 of FXN, there is a subset of patients harboring a heterozygous pathogenic small variant compound-heterozygous with a GAA repeat expansion. We report on the diagnostic journey of a 21-year-old patient who was clinically suspected of having FRDA at the age of 12 years. Genetic testing included fragment analysis, gene panel analysis and exome sequencing, which only detected one pathogenic heterozygous missense variant (c.389 G>T,p.Gly130Val) in FXN. Although conventional repeat analyses failed to detect GAA expansions in our patient, subsequent short-read genome sequencing (GS) indicated a potential GAA repeat expansion. This finding was confirmed by long-read GS, which in addition revealed a complex pattern of interruptions. Both large and small GAA expansions with divergent interruptions containing G, A, GA, GAG and/or GAAG sequences were present within one allele, indicating mosaic sequence variations. Our findings underscore the complexity of repeat expansions which can exhibit both interruptions and somatic instability. We also highlight the utility of long-read GS in unraveling intricate genetic profiles, ultimately contributing to more accurate diagnoses in clinical practice. Full article