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PubMed2025

Ataxia and oculomotor apraxia caused by a large-scale deletion in the senataxin gene.

Senataxin, an RNA/DNA helicase, is a key protein providing genome stability and one of the best characterized R-loop-binding factors playing an important role in transcription and DNA repair processes. Pathogenic SETX gene variants cause autosomal recessive spinocerebellar ataxia with axonal neuropathy (AOA2, MIM #606002) and autosomal dominant juvenile amyotrophic lateral sclerosis (ALS4, MIM #602433), rare neurodegenerative disorders characterized by juvenile onset of progressive cerebellar ataxia, axonal sensorimotor peripheral neuropathy, combined upper and lower motor neuron symptoms, and increased serum alpha-fetoprotein (AFP; specific for AOA2). We report two cases of adult patients presenting with cerebellar syndrome, scanned speech, and exercise intolerance which started in the second/third decade of life and were followed by muscle weakness and impaired gait coordination. Whole exome sequencing (WES) was performed to analyze single nucleotide and copy number variants. A decreased coverage of a genomic region of around 16 kb on chromosome 9 (chr9:132,295,852-132,311,876), suggesting a deletion encompassing 5 exons of the SETX gene (exons 11-15, NM_015046.7) was observed. This homozygous SETX (9q34.13) deletion leads to a frame shift and consequently truncation of the helicase domain in the protein. Loss-of-function variants in the SETX gene are known to be pathogenic. Statistical analysis of NGS data from the Polish population identified a few heterozygous carriers, suggesting its region-specific origin.

Humans↗

PubMed1986

Close linkage of human chromosomal pepsinogen A genes.

We have obtained a clone containing two pepsinogen A genes in a single insert by screening a recombinant cosmid library for human genomic DNA. Restriction endonuclease mappings of this cloned DNA showed that these two genes are very similar, but distinct in structure, and that they are closely linked to one another in the human chromosome DNA. The close arrangement of the genes with very similar structures could facilitate the homologous recombination or the unequal crossing-over which accounts for high frequency of haplotype variation in copy number of pepsinogen A genes as reported by Taggart et al.

Cloning, Molecular↗

PubMed1984

Tandem repeated DNA in an intergenic region of herpes simplex virus type 1 (Patton).

When the entire US region of HSV-1 (Patton) was cloned as an EcoRI fragment in bacteriophage lambda gtWES, the BamHI B6B5 fragment was observed to vary in size among independent isolates [Umene and Enquist, Gene 13 (1981) 251-268]. This fragment polymorphism also occurred in DNA of HSV-1 single plaque isolates. We report here that this heterogeneity is due to variation in copy number of a 15-bp tandem repeat of sequence 5'-CCACTCCCCACCCAC-3', which apparently lies in an intergenic region of the HSV-1 DNA.

Base Sequence↗

PubMed2026

Chromosome-scale genome remodeling in tumor evolution: Copy number alterations and structural variants as two sides of the same coin.

Chromosome-scale genomic rearrangements are a dominant force in tumor evolution. Copy-number alterations (CNAs) and structural variants (SVs) constitute two complementary axes of this process. Although detection technologies now deliver near-comprehensive catalogs, technical resolution has outpaced conceptual integration. In this review, we frame CNAs and SVs as inextricable facets of chromosomal aberrations. They reshape cancer genomes through altered gene dosage and three-dimensional regulatory rewiring. CNAs quantify the gene-dosage imbalance, yet arise through mechanistically distinct routes. Segmental CNAs typically require chromosomal breakage, and therefore often coincide with SV junctions. By contrast, whole-chromosome aneuploidy and whole-genome doubling (WGD) primarily reflect mitotic or cytokinetic failure and can occur without local breakpoints, while nevertheless reshaping the karyotypic landscape and seeding subsequent structural complexity. SVs, in turn, range from unbalanced events that alter copy number to ostensibly balanced exchanges that predominantly rewire regulatory architecture. Despite their diverse and sometimes catastrophic architectures, SVs are ultimately rooted in double-strand break formation and error-prone resolution. By integrating CNAs and SVs within a unified mechanistic and functional framework, we aim to convert catalogs into concepts and distill the organizing principles that govern tumor genome evolution.

Humans↗

PubMed2025

Assessment of the variant prioritization strategy for genomic newborn screening in the Generation Study.

PURPOSE: Genomic sequencing offers the opportunity to screen for hundreds of rare genetic conditions. To minimize potential negative impact on families and clinical services, it is crucial to reduce false-positive results while prioritizing clinical utility. We present an automated variant prioritization approach in the Generation Study, a research study investigating genomic sequencing in 100,000 newborns in England. Prioritized variants will subsequently undergo manual review by a registered clinical scientist and a specialist clinician before being reported back to parents. METHODS: We assessed specificity of our automated variant prioritization approach in 34,410 samples not enriched for rare diseases and sensitivity in 546 samples from patients with diagnostic variants in genes relevant to newborn screening. We used coverage and copy-number variants callability metrics to evaluate variant detection. RESULTS: We estimated that 3% to 5% of samples will have prioritized variants that require manual review and that <1% of cases will have reportable variants requiring further confirmation of the condition. Sensitivity in genes included in the Generation Study was estimated to be approximately 80%. Gene-level specificity results led to changes in variant prioritization rules and conditions that are included. CONCLUSION: Gene-specific assessment of variant prioritization is crucial to establish analytical validity prior to inclusion in genomic newborn screening.

Humans↗

PubMed2025

De novo rare EMX2 variants lead to idiopathic hypogonadotropic hypogonadism.

PURPOSE: The genetic etiology of infertility remains unknown. To identify genes for human infertility, we applied a de novo variant analysis in 142 parent-proband trios with idiopathic hypogonadotropic hypogonadism (IHH), an infertility disorder caused by gonadotropin-releasing hormone (GnRH) deficiency. METHODS: Rare de novo copy-number and single-nucleotide variants (CNVs and SNVs) were called from exome sequencing data of the IHH trios. An association study of common EMX2 variants and disease outcomes was performed in the Massachusetts General Brigham Biobank (N = 65,253). GnRH neuronal development and migration was studied in organotypic explants with knocked down of Emx2 and in a mouse model lacking Emx2. RESULTS: We identified that the gene EMX2 harbored both rare de novo CNVs and SNVs. Rare de novo EMX2 variants led to IHH, developmental delay, and hearing loss. Common EMX2 variants were linked to infertility, Parkinson disease, and hearing loss. Knockdown of Emx2 in nasal explants resulted in attenuated GnRH cell migration and GnRH cells were confined to nasal regions of Emx2 knockout (KO) mice, consistent with IHH pathogenesis. CONCLUSION: By utilizing a de novo variant analysis and cellular assays, EMX2 was uncovered as a gene for human infertility.

Humans↗

PubMed2026

Adult outcomes of clinically relevant genomic disorders: A systematic review and meta-analysis.

PURPOSE: Genomic disorders comprise a major source of human disease with survival into adulthood for most individuals, but data on adult outcomes are limited. METHODS: We conducted a formal search to identify studies of 14 clinically relevant, molecularly confirmed deletion syndromes with ≥5 adults reporting on prevalence of cardiovascular risk and other outcomes. Outcomes were pooled across deletion syndromes and by syndrome, using random-effects models. RESULTS: Of 1352 studies screened, 53 reported on nonoverlapping samples of 13 deletion syndromes. Estimated pooled prevalences, at age <30-40 for most, included 47% (95% CI 33-57%; n = 2076) for obesity, and for 10 deletion syndromes: diabetes 24% (95% CI 17-33%; n = 1739), hypertension 36% (95% CI 28-33%; n = 1314), and dyslipidemia 29% (95% CI 22-36%; n = 1127). High heterogeneity for each outcome was partly explained by a significant subgroup effect of individual syndrome. The few available mortality studies indicated premature mortality. CONCLUSION: Pooled results suggest that, although there may be elevated prevalence of adult cardiovascular risk conditions, high heterogeneity indicates caution when considering rare deletion syndromes collectively. The paucity of data extending into later adulthood and using age-matched control comparisons supports the need for prospective studies of large, well-phenotyped cohorts to inform adult penetrance of treatable medical diseases in this emerging group of young adults.

Humans↗

PubMed2026

Correspondence on "Optical mapping in Black genomes: Distinct LCR22 structures and 22q11.2 deletion syndrome mechanisms" by Pastor et al.

Explore the source record for details and available documents.

22q↗

PubMed2026

"Tissue-specific mitochondrial dysfunction in keratoconus: An integrated structural, genomic, and functional analysis".

PURPOSE: Keratoconus (KC) is a progressive corneal ectasia characterized by stromal thinning, conical protrusion, and irregular astigmatism, leading to visual impairment. Although oxidative stress is implicated in KC, the role of mitochondrial dysfunction remains unclear. We evaluated mitochondrial structural, genomic, and functional abnormalities in corneal tissues and blood from KC patients. METHODS: This prospective study enrolled 110 KC patients and 55 controls. Transmission electron microscopy (TEM) and immunohistochemistry (IHC) were performed on epithelial and stromal tissues from 10 KC to 5 control corneas assessing mitochondrial morphology, oxidative phosphorylation (OXPHOS) complexes and pro-apoptotic protein NOXA. Whole mitochondrial DNA (mtDNA) sequencing and relative mtDNA copy number analysis were performed on paired blood and corneal tissues from 50 KC patients and 35 controls including both epithelial and stromal samples. Gene expression of mitochondrial biogenesis and oxidative stress-related genes was analysed by qRT-PCR in corneal epithelium from independent 50 KC patients and 15 controls. RESULTS: TEM revealed cristolysis, membrane disruption, and reduced mitochondrial density in KC corneas. IHC showed reduced expression of OXPHOS complexes and increased NOXA expression (p < 0.05). Sequencing identified 1107 mtDNA variants, with more variants in corneal tissues than matched blood (929 vs. 576; p = 0.0002). Recurrent likely pathogenic variants were enriched in complex I-encoding genes (ND4, ND5). KC corneas showed reduced mtDNA copy number, downregulated POLRMT, upregulated NOX4, and significant downregulation of multiple antioxidant genes (p < 0.0001). CONCLUSION: KC patients exhibit tissue-specific mitochondrial abnormalities and impaired oxidative stress regulation, supporting a role for mitochondrial dysfunction in disease pathogenesis and highlighting potential therapeutic targets.

Corneal pathology↗

PubMed2024

Targeted Dynamic Phospho-Proteogenomic Analysis of Gastric Cancer Cells Suggests Host Immunity Provides Survival Benefit.

Despite of massive emergence of molecular targeting drugs, the mainstay of advanced gastric cancer (GC) therapy is DNA-damaging drugs. Using a reverse-phase protein array-based proteogenomic analysis of a panel of 8 GC cell lines, we identified genetic alterations and signaling pathways, potentially associated with resistance to DNA-damaging drugs, including 5-fluorouracil (5FU), cisplatin, and etoposide. Resistance to cisplatin and etoposide, but not 5FU, was negatively associated with global copy number loss, vimentin expression, and caspase activity, which are considered hallmarks of previously established EMT subtype. The segregation of 19,392 protein expression time courses by sensitive and resistant cell lines for the drugs tested revealed that 5FU-resistant cell lines had lower changes in global protein dynamics, suggesting their robust protein level regulation, than their sensitive counterparts, whereas the cell lines that are resistant to other drugs showed increased protein dynamics in response to each drug. Despite faint global protein dynamics, 5FU-resistant cell lines showed increased signal transducer and activator of transcription 1 phosphorylation and PD-L1 expression in response to 5FU. In publicly available cohort data, expression of signal transducer and activator of transcription 1 and NFκB target genes induced by proinflammatory cytokines was associated with prolonged survival in GC. In our validation cohort, total lymphocyte count, rather than PD-L1 positivity, predicted a better relapse-free survival rate in GC patients with 5FU-based adjuvant chemotherapy than those with surgery alone. Moreover, total lymphocyte count+ patients who had no survival benefit from adjuvant chemotherapy were discriminated by expression of IκBα, a potent negative regulator of NFκB. Collectively, our results suggest that 5FU resistance observed in cell lines may be overcome by host immunity or by combination therapy with immune checkpoint blockade.

Stomach Neoplasms↗

PubMed2025

Methylation Signatures Identify Two Distinct Clusters of Uterine Leiomyosarcoma With Unique Histologic and Clinical Behaviors.

Uterine leiomyosarcoma (uLMS) is a rare and deadly gynecologic malignancy. uLMS is histologically heterogeneous and presents with a wide spectrum of tumor differentiation, with a broad range of genomic DNA instability, which can make the diagnosis and prognosis of uLMS challenging. Methylation has emerged as a useful molecular tool in tumor classification and diagnosis in certain neoplasms. We initiated this study to investigate the role of global methylation in the differential diagnosis of uLMS from its mimics in correlation with pathologic characteristics and clinical outcomes. In this study, we performed array-based global methylation profiling analysis in a total of 71 uLMS and compared the methylation signatures of uLMS with several other uterine mesenchymal tumors and soft tissue leiomyosarcoma. We found that uLMS demonstrated distinct methylation patterns differing from all other tumor types. Notably, methylation profiling defines 2 distinct subgroups of uLMS with differing copy number alterations, resulting in unique histologic and clinical behaviors, further emphasized by differences in methylation pathway analysis. This study is the first to report methylation profiling as a useful diagnostic tool in differentiating uLMS from mimics and defines 2 subtypes of uLMS based on methylation signatures.

Humans↗

PubMed2026

Copy Number-low/TP53-mutated Endometrial Cancer With Wild-type p53 Immunoexpression: Implications for Risk Stratification and Management When Using Next-generation Sequencing for Molecular Classification.

Endometrial cancers with the Cancer Genome Atlas (TCGA) molecular profile of TP53-mutated, POLE-wild-type, and microsatellite-stable generally exhibit a high burden of copy number (CN) alterations and carry an increased risk for adverse outcomes, meriting maximal adjuvant therapy. In contrast, the prognosis associated with a TP53 mutation that coexists with a POLE mutation or microsatellite instability aligns with that of ultramutated or hypermutated cancers, respectively. In this study, we characterized a rare molecular subclass of endometrial cancers defined by TP53 mutation but low burden of CN alterations, wild-type p53 immunoexpression (immunohistochemistry [IHC]), and low TP53 variant allele frequency (median 13% and maximum 47%). Among 723 consecutive endometrial cancers prospectively classified using next-generation sequencing, 16 (2.2%) were CN-low/TP53-mutated/p53 wild-type IHC. Two additional cases were identified in a separate retrospective cohort of 32 recurrent low-grade early-stage endometrial cancers, bringing the total to 18 cases. They affected postmenopausal patients, exhibited low-grade endometrioid histotype, and were mostly confined to the uterus without lymphovascular space invasion. The recurrence rate was 6.25% (1/16) in the prospective cohort, and none died, placing their prognosis closer to that of CN-low than CN-high cancers. We conclude that next-generation sequencing-based TCGA classification of TP53-mutated, POLE-wild-type, microsatellite-stable endometrial cancers with TP53 variant allele frequency < 50% requires further evaluation using CN analysis and/or p53 IHC to detect this rare molecular category. IHC-based TCGA classification, such as the ProMisE protocol, will not be able to detect these cases because the p53 IHC pattern is wild-type and there are no distinguishing morphological features; this may be of relevance for analyzing ProMisE protocol-based clinical trials and outcomes studies. Long-term outcome studies are needed to refine risk stratification and treatment decisions for this unique molecular class of endometrial cancers that further contributes to the evolving understanding that the clinical significance of TP53 mutation in endometrial cancer is complex and depends on coexisting molecular alterations.

Humans↗

PubMed1998

The genomic organization of non-LTR retrotransposons (LINEs) from three Beta species and five other angiosperms.

We have isolated and characterized conserved regions of the reverse transcriptase gene from non-LTR retrotransposons, also called long interspersed nuclear elements (LINEs), from Beta vulgaris, B. lomatogona and B. nana. The novel elements show strong homology to other non-LTR retrotransposons from plants, man and animals. LINEs are present in all species of the genus Beta tested, but there was variation in copy number. Analysis by Southern hybridization and fluorescent in situ hybridization revealed the clustered organization of these retroelements in beet species. PCR amplification using degenerate primers to conserved motifs of the predicted LINE protein sequence enabled the cloning of LINEs from both Monocotyledonae (Allium cepa, Oryza sativa and Secale cereale) and Dicotyledonae (Nicotiana tabacum and Antirrhinum majus) indicating that LINEs are a universal feature of plant genomes. A dendrogram of fifteen new and six previously isolated sequences showed the high level of sequence divergence while revealing families characteristic of some genera. The genomic organization of non-LTR retrotransposons was examined more detailed in A. majus and O. sativa.

Amino Acid Sequence↗

PubMed2026

Assessing the de novo paradigm in sporadic early-onset Alzheimer disease trios.

The genetic architecture of sporadic Early-Onset Alzheimer Disease (sEOAD, onset ≤65 years) remains largely unknown. To assess the de novo mutation (DNM) hypothesis, we performed a nationwide recruitment of 37 novel sEOAD patients-unaffected parents trios. After assessing known monogenic genes, we performed trio-based exome sequencing and jointly analyzed novel trios with 12 previously reported ones. Of these, we selected 16 trios for genome sequencing. We identified three patients with a pathogenic DNM in APP or PSEN1. Then, from the 46 remaining trios, we identified 38 non-synonymous coding DNM and 4 de novo copy number variants (CNVs) in exome data. Four DNM (2 novel, in SPHK2 and DDR1) and bi-allelic inherited variants in two genes affected Alzheimer disease-related genes. No significant burden of rare coding variants in exome/genome data from 5643 EOAD cases and 16097 controls was identified using nested windows centered on each DNM position, at the transcript level. From genome data, one non-coding DNM was predicted to affect splicing in an AD-associated gene, PINX1. Overall, 48% probands carried ≥1 inherited risk factor with odds ratio (OR) > 1.5 and GWAS-defined Genetic Risk Scores (GRS) distribution was more consistent with random distribution than enrichment in higher scores in probands. We confirm that DNMs in known monogenic genes explain sEOAD in a minority of cases, while candidate DNMs in other genes might account for a small proportion of additional cases. The majority of sEOAD patients may have a complex etiology including multiple inherited variants, however, GRS might not explain most of its genetic component.

Humans↗

PubMed2021

1q21.1 distal copy number variants are associated with cerebral and cognitive alterations in humans.

Low-frequency 1q21.1 distal deletion and duplication copy number variant (CNV) carriers are predisposed to multiple neurodevelopmental disorders, including schizophrenia, autism and intellectual disability. Human carriers display a high prevalence of micro- and macrocephaly in deletion and duplication carriers, respectively. The underlying brain structural diversity remains largely unknown. We systematically called CNVs in 38 cohorts from the large-scale ENIGMA-CNV collaboration and the UK Biobank and identified 28 1q21.1 distal deletion and 22 duplication carriers and 37,088 non-carriers (48% male) derived from 15 distinct magnetic resonance imaging scanner sites. With standardized methods, we compared subcortical and cortical brain measures (all) and cognitive performance (UK Biobank only) between carrier groups also testing for mediation of brain structure on cognition. We identified positive dosage effects of copy number on intracranial volume (ICV) and total cortical surface area, with the largest effects in frontal and cingulate cortices, and negative dosage effects on caudate and hippocampal volumes. The carriers displayed distinct cognitive deficit profiles in cognitive tasks from the UK Biobank with intermediate decreases in duplication carriers and somewhat larger in deletion carriers-the latter potentially mediated by ICV or cortical surface area. These results shed light on pathobiological mechanisms of neurodevelopmental disorders, by demonstrating gene dose effect on specific brain structures and effect on cognitive function.

Brain↗

PubMed2025

Molecular analysis of lung adenocarcinomas from the SAFIR02-Lung cohort reveals new metastasis-associated copy-number alterations including frequent mutant-specific KRAS-allelic imbalance and identifies CDKN2A homozygous deletions as an independent biomarker of poor prognosis.

BACKGROUND: Identifying molecular alterations specific to advanced lung adenocarcinomas could provide insights into tumour progression and dissemination mechanisms. METHOD: We analysed tumour samples, either from locoregional lesions or distant metastases, from patients with advanced lung adenocarcinoma from the SAFIR02-Lung trial by targeted sequencing of 45 cancer genes and comparative genomic hybridisation array and compared them to early tumours samples from The Cancer Genome Atlas. RESULTS: Differences in copy-number alterations frequencies suggest the involvement in tumour progression of LAMB3, TNN/KIAA0040/TNR, KRAS, DAB2, MYC, EPHA3 and VIPR2, and in metastatic dissemination of AREG, ZNF503, PAX8, MMP13, JAM3, and MTURN. Conversely, no meaningful difference was found in pathogenic single-nucleotide variant frequencies, reinforcing the notion that they are early events in tumorigenesis. CDKN2A homozygous deletion was linked to poor clinical outcome in patients with early tumours (overall survival hazard ratio 2.17, 95% CI: 1.43-3.28, corrected p-value = 0.01). Furthermore, we found that KRAS mutant allele specific imbalance, i.e. focal amplification of the mutant allele, is more prevalent in locoregional or distant samples of metastatic patients than in early lesions (8.4%, 13% and 2.8% respectively). This observation was replicated in three public cohorts. Tumours with KRAS mutant allele specific imbalance show specific patterns of co-occurrence and mutual exclusion with alterations in key cancer genes like CDKN2A, TP53, STK11 and NKX2-1, often in a tumour type dependent manner. CONCLUSION: Advanced LUAD tumours exhibit higher copy-number alteration burden, with distinct alterations associated with tumour progression and metastasis. CDKN2A homozygous deletions predict poor prognosis in early disease, while KRAS mutant allele-specific imbalance is enriched in advanced tumours.

Humans↗

PubMed2021

Whole-genome sequencing reveals progressive versus stable myeloma precursor conditions as two distinct entities.

Multiple myeloma (MM) is consistently preceded by precursor conditions recognized clinically as monoclonal gammopathy of undetermined significance (MGUS) or smoldering myeloma (SMM). We interrogate the whole genome sequence (WGS) profile of 18 MGUS and compare them with those from 14 SMMs and 80 MMs. We show that cases with a non-progressing, clinically stable myeloma precursor condition (n = 15) are characterized by later initiation in the patient's life and by the absence of myeloma defining genomic events including: chromothripsis, templated insertions, mutations in driver genes, aneuploidy, and canonical APOBEC mutational activity. This data provides evidence that WGS can be used to recognize two biologically and clinically distinct myeloma precursor entities that are either progressive or stable.

DNA Copy Number Variations↗

PubMed2026

Plasticity of extrachromosomal DNA segregation during drug adaptation.

Uneven segregation during mitosis is a striking feature of extrachromosomal DNA (ecDNA). Because ecDNA lacks a centromere, it is thought to segregate stochastically, generating intratumoral heterogeneity in genomic copy number. Drug treatment can readily change ecDNA copy number, enabling cells to acquire drug resistance, yet whether these changes reflect static selection of pre-existing clones or active reconfiguration under stress remains unresolved. To address this, we develop a high-throughput framework combining single-cell DNA sequencing with cellular barcoding for clonal tracking. Single-cell cloning reveals that not all clones exhibit identical segregation modes even under drug-free conditions. Under treatment, resistant populations do not simply arise from pre-existing clones with favorable ecDNA states; instead, some clones actively reconfigure their segregation behavior to generate resistant cells. Thus, although ecDNA generally segregates stochastically, it can undergo nonrandom, actively regulated segregation under drug stress, raising the possibility of therapeutically targeting ecDNA segregation mechanisms to counteract adaptive resistance.

Extrachromosomal DNA↗