The development of industrial operations has led to a significant rise in human contact with environmental toxins, especially for individuals who live close to steel industries and petroleum refineries. Public health is seriously threatened by the potential for genetic impairment from continued exposure to these emissions. Chromosomal aberration (CA) and micronucleus (MN) assays were used in this study as reliable biological markers to assess DNA damage in people who lived close to a steel factory and an oil refinery in Iraq's Erbil Province. Blood and buccal samples were collected from 50 exposed males and 15 control participants who resided in an area free from industrial impact. Micronuclei were counted in hematoxylin-eosin-stained buccal smears, while chromosomal alterations were examined in Giemsa-stained lymphocyte cultures. The statistical analysis was performed with GraphPad Prism (version 10). According to the findings, the exposed group had a considerably higher frequency of micronucleated cells and total chromosomal alterations (p < 0.001) than the controls. Individuals who lived near industrial areas exhibited much higher levels of specific structural damage, including pulverization, exchange fragments, and dicentric and ring chromosomes, indicating ongoing genotoxic stress from extended exposure to contaminated air. In summary, the results provide the first cytogenetic evidence of measurable DNA damage associated with extended exposure to pollutants from the steel and petroleum industries in the province of Erbil. These genetic changes may increase the risk of cancer, highlighting the critical need for better environmental management, ongoing health surveillance, and preventive measures in communities near industrial complexes.

54. Ring chromosome 14 in a case of acute myeloid leukaemia with the MECOM-ETV6 translocation - a case report.

Unravelling ring chromosome structures and formation mechanisms by short-read and long-read genomic sequencing

Response to vagus nerve stimulation in people with ring chromosome 20.

Objective: To analyze the clinical features and diagnostic process of ring chromosome syndrome. Methods: Clinical data of 9 children with ring chromosome syndrome who were treated at the Children's Medical Center of Peking University First Hospital from September 2009 to May 2025, were summarized and analyzed in a case series study. The data included clinical manifestations, types of epileptic seizures, genetic testing, treatment outcomes, and follow-up results, et al. Results: Among the 9 children with ring chromosome syndrome, there were 6 girls and 3 boys, including 4 children with ring chromosome 20 syndrome, 3 children with ring chromosome 14 syndrome, and 1 child each with ring chromosome 13 and 17 syndrome. All 9 children had de novo chromosomal variations. Among them, 3 children of ring chromosome 20 syndrome were mosaic, and the remaining 6 children were non-mosaic. All 9 children exhibited diverse clinical features, especially those with ring chromosome 20 syndrome, which presented with specific manifestations. The 4 children with ring chromosome 20 syndrome all had acute epileptic seizures as the initial symptom, with onset ages of 67, 39, 17, and 96 months, and all had focal seizures. One child with ring chromosome 20 syndrome had non-convulsive status epilepticus. Development of all 4 children with ring chromosome 20 syndrome was normal before seizure onset, but 3 children showed regression after onset. No physical deformities were observed in 4 children with ring chromosome 20 syndrome, and 2 children were misdiagnosed, 3 children underwent whole exome sequencing and copy number variation analysis in their families, with no abnormalities detected. All 4 children with ring chromosome 20 syndrome were diagnosed through chromosomal karyotype analysis, the intervals between onset and diagnosis were 2, 81, 19 and 13 months, respectively. Follow-up showed that epileptic seizures were not controlled in all 4 children with ring chromosome 20 syndrome. The other 5 children were characterized by developmental delay as the initial symptom, followed by epileptic seizures between 3 and 24 months of age. Developmental regression of the other 5 children did not occur after onset, 2 of them had microcephaly, and 3 had wide-set eyes. No misdiagnoses were reported in these 5 children, and the intervals between onset and diagnosis were 7, 3, 55, 3, and 106 months, respectively. Follow-up showed that epileptic seizures were controlled in these 5 children. Conclusions: Ring chromosome 20 syndrome typically manifest with epilepsy as the initial symptom and are refractory to drug treatment, their early development is entirely normal. Ring chromosome 13, 14, and 17 syndrome are characterized by developmental delay from an early age, followed by the onset of epileptic seizures, which are easily controlled. Conventional whole-exome sequencing and copy number variation analysis in families rarely detect ring chromosome abnormalities. Early chromosomal karyotype analysis is essential for the diagnosis of ring chromosome syndrome.

Human ring chromosomes (RCs) constitute one of the rarest described inborn chromosomal rearrangements. At first, they seem to be just another subgroup of structural chromosomal aberrations like translocations, inversions, or insertions. However, RCs are more complex, as they almost always occur in conjunction with a mosaic karyotype constitution, resulting in mosaic monosomy of the affected chromosome. Most likely due to the latter effect, a genotype-phenotype correlation is still not available. To proceed with solving this problem, a new database is presented here, which summarizes all constitutional RCs– currently, ~1900 cases have been included. The RC-database (&lt;a href="https://cs-tl.de/DB/CA/RC/0-Start.html"&gt;https://cs-tl.de/DB/CA/RC/0-Start.html&lt;/a&gt;) has been included in the ChromosOmics database (&lt;a href="https://cs-tl.de/DB.html"&gt;https://cs-tl.de/DB.html&lt;/a&gt;), which already consists of a corresponding collection on small supernumerary marker chromosomes, chromosomal heteromorphisms, constitutional chromosomal breakpoints, and uniparental disomy. Like all others, the RC-database is freely accessible. As first results, the approximate frequency of RCs per chromosome can be assessed, and it can be suggested that the number of RC-carriers with no or minor clinical signs and symptoms is overall ~8%. However, the latter varies clearly according to the chromosomal origin of the RC.&lt;strong&gt;Keyword&lt;/strong&gt;&lt;strong&gt;s&lt;/strong&gt;Mosaic; copy number variation (CNV); subtelomeric loss; infertility; ring chromosome

Background/Objectives: Ring chromosomes (RCs) can be rare or common depending on the chromosome involved. With interest in the historical RCs identified by our laboratory, we curated instances to provide further information to this research field. Methodology: We carried out a retrospective, single-center study of constitutional RCs identified starting in the late 1980s. Details for 40 RCs with a modal number of 46 chromosomes are featured here. Results: Mosaic and non-mosaic RCs are identified, with a preponderance of pediatric-aged females at first ascertainment. We corroborated an enrichment for acrocentric and X chromosome RCs. Six were ascertained perinatally, with peripheral blood being the most commonly studied postnatal specimen type. Notable RCs included a female fetus with an increased risk for monosomy X, whose mosaic RCY arose secondary to a translocation between the sex chromosomes. In another, a series of complex events formed three structurally aberrant chromosomes, including an RC4 with loss of 4p16.3, corresponding with the observed phenotypic expression of Wolf-Hirschhorn syndrome. In another, a mosaic RCX was co-identified with an isochromosome 21q, resulting in a dual diagnosis of trisomy 21 and Turner syndrome. In another, the atypical RC21 structure raises the possibility of a complex rearrangement. Chromosomal microarray data clarified breakpoints and gene dosage imbalances in fifteen, while low-level mosaicism for the RC escaped detection by array in another. Eight RCs were de novo, and parental exclusion was documented for six. Conclusions: This study illustrates the need for cytogenomic follow-up to improve the literature for patients with RCs.

Background/Objectives: Chromosome microarrays (CMAs) tend to be used as the first line test or as a test that does not require confirmation or verification by a second test. However, to understand the implications of a duplication or deletion for a family seeking genetic counseling, it is crucial to know the nature of the underlying chromosomal rearrangement. Here, we present seven cases with apparent isolated copy number loss, five of which showed unexpected complexity. Methods: Seven cases were investigated by CMA due to intellectual disability and/or dysmorphic features. Isolated deletions ranging in size from ~0.6 to ~21 Mb were found and referred for further characterization of the underlying chromosomal rearrangement. To elucidate the cases, fluorescence in situ hybridization was performed using locus-specific, whole and partial chromosome painting and/or multicolor banding. Results: Among the seven selected cases, there were five with unexpected complexity. Isolated deletions were actually evidence of chromoanasynthesis, ring chromosome formation, unbalanced translocation, or unbalanced insertion. Conclusions: These results clearly underscore that it seems reasonable to examine every case with a copy number variant—even if it appears to be “only” a simple partial deletion—using banding and/or molecular cytogenetic testing in order to make a qualified assessment of the situation and, on this basis, ensure sound genetic counseling.

BACKGROUND: Chronic radiation exposure due to residence in areas contaminated with radionuclides remains a pressing concern globally, as it increases the risk of leukemia, solid malignancies, and other diseases. According to current understanding, many human pathologies are underpinned by somatic mosaic mutagenesis, particularly involving sex chromosomes. The X chromosome plays a critical role in immune function and autoimmune pathogenesis, and X chromosome aneuploidy is linked to development of various somatic disorders. Prior cytogenetic studies of radiation-exposed populations in the Southern Urals revealed increased X chromosome involvement in micronuclei formation, warranting further investigation into X chromosome aberrations. AIM: To assess intra- and interchromosomal aberrations involving the X chromosome in peripheral blood T lymphocytes in women with chronic radiation exposure during long-term follow-up. METHODS: This pilot study included five women exposed to chronic radiation in the Southern Urals (mean age: 74.0 ± 0.8 years; mean cumulative red bone marrow dose: 1.35 ± 0.30 Gy). A comparison group consisted of five women (mean age: 66.3 ± 1.2 years; mean red bone marrow dose: 0.010 ± 0.006 Gy; range: 0–0.03 Gy) who lived under similar socioeconomic conditions and had received less than 70 mGy of total red bone marrow exposure during follow-up. X chromosome aberrations were analyzed using multicolor banding (mBAND). Aberration frequency was calculated per genome equivalent, adjusted for donor age. The frequency of cells with X chromosome aneuploidy was also assessed. RESULTS: The frequency of X chromosome aberrations was higher in irradiated women compared to the comparison group (0.100 ± 0.036 vs 0.019 ± 0.011; U = 3, p = 0.0476). In irradiated women, a greater variety of aberration types was noted, including a ring chromosome, an isochromosome, and a chromosome presumably formed as a result of chromothripsis. The mean frequencies of X chromosome aneuploidy in irradiated women did not differ significantly from those in the comparison group (p = 0.4); however, interindividual variation may exist. CONCLUSION: The findings may indicate a more intense mutational process in individuals chronically exposed to radiation. The study of X chromosome aberrations in peripheral blood T lymphocytes of women chronically exposed to radiation in the Southern Urals is promising and should be continued.

Introduction: Ring chromosomes (RCs) are acquired circular structural abnormalities associated with gain or loss of genetic material, which are thought to be associated with inferior outcomes in patients with myeloid neoplasms (MNs). Responses of patients with MN and RC to the standard therapeutic options have not been previously reported. Methods: We analyzed the demographics and outcomes of 31 consecutive patients with an MN and RC, comparing overall survival (OS) and progression-free survival (PFS) of patients who received supportive care (n = 9), cytotoxic chemotherapeutic options (n = 3), hypomethylating agents (HMA) alone (n = 6), or HMA in combination with venetoclax (n = 13). Results: Over 60% of all patients with RC had either a TP53 mutation, loss of 17p, or both. Interestingly, 22/31 (71%) of patients had not received prior radiation or chemotherapy. Patients who received supportive care had a shorter OS (p = 0.001), but none of the therapeutic interventions were associated with further improvement in prolonging OS (p = 0.86) or PFS. The presence of a complex karyotype, TP53 mutations/loss of TP53, or a treatment-related MN was not independently associated with an inferior OS in MN patients with RCs. Conclusion: These findings indicate that patients with MN and RC have especially poor outcomes and that effective treatment strategies remain an unmet need.

Abstract Study question What are the mechanisms underlying segmental aneuploidy (SA) in preimplantation human embryos, and to what extent is there concordance between germ cell layers? Summary answer Segmental aneuploidy (SA) in IVF embryos predominantly arises from paternal meiotic errors, exhibiting deletion-duplications, inversions, and chromothripsis-like mechanisms, with rare SA concordance observed What is known already Segmental aneuploidy (SA) involves the gain or loss of chromosomal segments rather than entire chromosomes, leading to significant embryonic consequences such as implantation failure, spontaneous abortion, and congenital abnormalities. Identified in about 7% of aneuploid biopsies during preimplantation genetic testing for aneuploidy (PGT-A) and preimplantation genetic testing for structural rearrangements (PGT-SR), SA arises from chromosomal breakage and recombination during meiosis or early cleavage. These structural abnormalities disrupt gene dosage, potentially resulting in non-disjunction events or abnormal recombination, which affect normal embryonic development. Understanding SA mechanisms is crucial for improving outcomes in both natural conception and assisted reproductive technologies (ART). Study design, size, duration This single-centre retrospective study examined 101 blastocysts identified as aneuploid with segmental aneuploidy (SA) via a validated NGS-based PGT-A protocol. The protocol enables precise identification of the parental origin of SA (paternal or maternal) by integrating genotyping data with chromosomal copy number variation analysis. This method enhances understanding of SA mechanisms and their implications, contributing valuable insights into embryonic development and improving assisted reproductive technology (ART) outcomes. Participants/materials, setting, methods The participants in this study were couples undergoing IVF cycles with PGT-A from 2020–2024. Ethical approval was secured from IRAS (#294909) and HFEA licence (#R0208). Segmental aneuploidy (SA) was identified in embryos post-PGT-A. Participants provided cheek swabs for parental DNA analysis, and embryo biopsies included samples from the inner cell mass (ICM) and two trophectoderm (TE) biopsies. This approach enabled comprehensive analysis of SA origin and patterns in the context of preimplantation development. Main results and the role of chance In our analysis of a cohort exceeding 100 cases of segmental aneuploidy (SA), we examined both two trophectoderm (TE) biopsies and the inner cell mass (ICM) from each embryo. We frequently observed complex SA aneuploidies characterized by combinations of deletions, duplications, inversions, isochromosomes, and ring chromosomes, often localized to a single chromosome, with a notable prevalence of paternal errors. Interestingly, while mosaicism typically suggests post-zygotic origins, evidence from our data indicates meiotic origins for some cases, supporting the concept of “SA rescue,” where specific chromosomes can be restored to euploidy—a phenomenon not commonly associated with whole chromosome aneuploidy. Furthermore, unlike the typical concordance seen in whole chromosome aneuploidy, perfect concordance of SA abnormalities among the three sampled regions was rare. We identified an “intrachromosomal effect,” where additional SA abnormalities on the same chromosome were maintained across the biopsies, possibly related to chromothripsis. These observed patterns bear resemblance to chromosomal instability seen in cancer, leading to the hypothesis that tumor-like mechanisms might influence SA development during preimplantation human embryogenesis. Overall, while the study’s design minimizes chance influences, variability in SA manifestations calls for cautious interpretation of these complex genetic phenomena. Limitations, reasons for caution Limitations of this study include its retrospective and single-centre design, which may affect generalizability. The use of cheek swabs for parental DNA analysis might not capture full genetic variability, and biases could arise from sample handling and mosaicism. Further multicentre research is needed to validate the findings. Wider implications of the findings This study helps us inform future PGT strategies, it highlights the need to screen for (and, where possible reduce) chromosome breakage/DNA damage in IVF cases. It provides novel insight into the mechanisms of chromosome behaviour in early human development. It introduces novel concepts hitherto unreported in this context. Trial registration number No

Epilepsy associated with chromosomal disorders.

Ring chromosome formations are one of the rare genetic anomalies with a prevalence of 1:25,000 — 1:62,000 newborns. Ring chromosomes are formed as a result of sporadic terminal deletions of chromosomal arms, which then “stick together” and form a ring. In 1% of cases, ring chromosomes are inherited from parents. Chromosome 13 ring syndrome is a genetic disorder caused by an anomaly in chromosome 13. This syndrome is rare and is usually associated with a widely varying phenotype (from mild to severe). At the same time, the nature of clinical manifestations is associated with the length of the lost section of the chromosome and, as a result, the number of lost genes. The disease leads to a number of disorders: intrauterine growth retardation, short stature, moderate to severe moderate to severe intellectual disability, microcephaly, facial dysmorphic disorder, limb abnormalities and genital abnormalities. Additional signs have been reported, including behavioral problems, hearing and speech disorders, congenital heart defects, brain malformations, and anal atresia. The main diagnostic method is karyotyping, and the research material can be both amniotic fluid (prenatal diagnosis) and tissues of an already born child (postnatal diagnosis). The article, using a clinical case description as an example, examines the mechanisms of occurrence, main aspects of clinical manifestations, diagnosis, treatment and prognosis in a child with ring chromosome 13 syndrome.

Glyphosate resistance in crop weeds is commonly attributed to rapid evolution through the amplification of the target gene, EPSPS (5-enolpyruvylshikimate-3-phosphate synthase). This amplification typically occurs through mechanisms such as unequal recombination, segmental duplications within the target chromosome, or the formation of ring chromosomes and extrachromosomal circular (ecc) DNA elements containing EPSPS. However, structural abnormalities in chromosomes not directly associated with EPSPS amplification have not been documented in the glyphosate-resistant weed population. Here, we describe the presence of a large chromosome found exclusively in the glyphosate-resistantAmaranthus tuberculatus (waterhemp) population but absent in susceptible counterparts. This large chromosome (~ 6μm) is approximately twice the size of normal chromosomes (~ 2-3μm) and is present in both male and female euploid plants (2n = 32) in a heteromorphic state. It aroses through pericentromeric heterochromatin expansion and duplications of the 5S rDNA locus but notably lacks the EPSPS gene. The large chromosome pairs with its normal homolog but was not transmitted to progeny in controlled greenhouse matings, suggesting a fitness cost in the absence of glyphosate selection pressure. This large chromosome offers a potential resource for the investigation of chromosome evolution of adaptive traits for glyphosate resistance in A. tuberculatus.

Abstract Pancreatic cancer (PC) is the third leading cause of cancer deaths in US with a 5-year survival rate of 13%. Most patients are diagnosed at advanced stages, and conventional treatments remain ineffective and highly toxic to these patients as both chemotherapy and radiation affect normal, healthy cells, leading to adverse side effects. We have adapted CRISPR-Cas9 as a cancer-specific killing strategy that spares normal cells. CRISPR-Cas9 is a molecular scissor that induces DNA double strand breaks (DSBs) at its targeted genomic locations. We use CRISPR-Cas9 to target the subset of somatic mutations that create protospacer adjacent motifs (PAMs). Using S. pyogenes Cas9 that recognizes a 5’-NGG-3’ PAM, we identified somatic single base substitutions (SBSs) that give rise to novel PAMs (e.g. NCG→NGG), and use the upstream sequence to design sgRNAs for cancer-targeting. We have discovered that ∼13% of SBSs in PC form novel PAMs, and these cancer-specific sgRNAs exhibited on-target activity and lack of off-target events. Notably, while examining WGS data from rapid autopsy samples, we found that 90% of PAMs were maintained among primary carcinomas and metastases. Using multi-target sgRNAs targeting 2-16 sites in the non-coding regions of human genome, we demonstrate a dose-response relationship in which &amp;gt;10 target sites are required to achieve &amp;gt;99% cell elimination. Moreover, we established that simultaneous induction of multiple DSBs by CRISPR-Cas9 causes extreme chromosomal instability that ultimately leads to cell death. We detected massive chromosomal aberrations, including dicentrics, ring chromosomes, and polyploidization. Surprisingly, CRISPR-Cas9-induced DSBs are significantly more cytotoxic in PCs than a comparable number of radiation-induced DSBs, in which the number of DSBs required to achieve equitoxic effects was ∼3 times higher for radiation than CRISPR-Cas9. Finally, we have developed a pipeline to screen for the most toxic sgRNAs in a given PC for selective killing. Using our PAM-based approach, we identified &amp;gt;100 Panc10.05-specific sgRNAs that have no off-target activity at 0- and 1-mismatch sites. We cloned them into lentiviral vectors and transduced in bulk, followed by NGS to discover sgRNAs that decreased in representation in the targeted cell line but not in the controls. We selected the top sgRNAs that have 100% variant allele frequency (VAF), cloned 4 of them into a multi-sgRNA expression vector, and transduced it into co-cultures consisting of two PC cell lines. Greater than 85% selective reduction of the targeted cell line was detected. Then, we selected nine top sgRNAs, transduced them as a pool into Panc10.05 cell line, and injected these cells into athymic, nude mice for tumor growth. We observed &amp;gt;90% tumor growth inhibition with these cancer-specific sgRNAs. Overall, our study highlights the therapeutic potential of CRISPR-Cas9 as an anti-cancer strategy and supports the genetic targeting of PCs. Citation Format: Selina Shiqing K. Teh, Akhil Kotwal, Kirsten Bowland, Alexis Bennett, Eitan Halper-Stromberg, Laura Morsberger, Sarah Wheelan, Nicholas J. Roberts, Chien-Fu Hung, Michael Goldstein, Ying S. Zou, James R. Eshleman. CRISPR-Cas9 as a novel cancer gene therapy approach against pancreatic cancers [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2025; Part 1 (Regular Abstracts); 2025 Apr 25-30; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2025;85(8_Suppl_1):Abstract nr 471.

Abstract Introduction: Undifferentiated sarcomas (USrc) are aggressive mesenchymal tumors that do not show characteristic features and therefore remain a diagnosis of exclusion. USrc typically have a low tumor mutational burden but are genomically complex, carrying many large structural variants (SVs) and copy number aberrations (CNAs). Improving diagnostic practice by adding novel whole genome-technologies based on high molecular weight DNA could increase the sensitivity for detecting genetic alterations in USrc, allowing identification of recurrent aberrations or patterns with clinical implications. Methods: Snap-frozen tissue from 41 USrc in 38 patients were analyzed by both conventional karyotyping and Optical Genome Mapping (OGM). Chromothripsis was determined based on OGM data and defined as more than eight copy number segments with oscillating copy number in co-occurrence with more than eight chromosomal rearrangements within 50 Mb, or more than 20 rearrangements within 50 Mb. These rearrangements should be interleaved and approximately half of them should be inversion-type aberrations. In addition, we identify known cancer genes (COSMIC Cancer Gene Census) which are amplified/lost or show evidence of disruptive SVs. DNA methylation profiling using EPIC arrays was done on 15 USrc followed by sarcoma classification with the Deutsches Krebsforschungszentrum (DKFZ) sarcoma classifier (v12.3). Results: 32 out of 41 USrc karyotypes showed at least subclonal whole genome-doubling with complex patterns of SVs and CNAs, including double minutes, ring chromosomes and giant markers. OGM was performed on all USrc biopsies yielding an average coverage of 352X. 25 out of 38 patient samples presented with chromothripsis with an average of 4.3 chromosomes affected (1-13 chromosomes). 70% of amplifications (CN greater than or equal to 5) and 83% of high, focal amplifications (CN greater than or equal to 10) occurred in regions with chromothripsis. Aberrations in 590 COSMIC cancer genes were detected. The most frequently altered cancer genes were CDKN2A (42%), RB1 (34%), PTPRD (29%), MGMT (26%), and ARHGEF12 (24%). For 3 patients, biopsies from two different time points were profiled, showing a high proportion of shared aberrations. DNA methylation patterns classified 8 out of 15 analyzed samples as USrc, and the remaining 7 showed no match to any reference sarcoma group. Copy number profiles derived from OGM and DNA methylation arrays were near identical. MGMT promotor hypermethylation was observed in 5 out of 16 cases. Conclusion: Implementation of OGM improves the detection of SVs and CNAs over standard-of-care. This is demonstrated by the detection of chromothripsis regions and novel recurrent aberrations in USrc. Further investigation to confirm these findings and to identify single nucleotide variants and allele-specific copy numbers are currently ongoing using long-read HiFi sequencing (PacBio). Citation Format: Jef Baelen, Raphael Sciot, Ruben Cools, Jonas Demeulemeester, Isabelle Vanden Bempt. Deep genomic analysis of undifferentiated sarcoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2025; Part 1 (Regular Abstracts); 2025 Apr 25-30; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2025;85(8_Suppl_1):Abstract nr 7177.

Individuals with Turner syndrome (TS) phenotypes may exhibit short stature, ovarian dysfunction, and neurocognitive disorders. Their genomes can include ring chromosomes formed from the X chromosome (RCX). Here, we present cytogenomic and clinical findings from seventeen individuals with TS who bore mosaic forms of RCX and frequently presented with short stature and concern for TS. The subjects were retrospectively included and tested at a single-site cytogenetics laboratory for over 42 years. Here, we illustrate each subject’s comprehensive cytogenetic workup and phenotypes. The cohort shows comorbidities and sexual characteristics associated with mosaic RCX. These cytogenetic findings and clinical features are distinct from those of individuals with non-mosaic TS. Studying the pattern of X-activation across tissues in this cohort could provide additional data on a postulated source of phenotypic variability. Current guidelines recommend karyotype as the first-line test rather than SNP microarray analysis when aneuploidy is suspected. Conventional cytogenetics is still necessary to understand structural abnormalities, provide genomic context, and detect low-level mosaicism. These cases add to the knowledge of mosaic RCXs and offer new clinical laboratory information that is important for diagnosis and useful for comprehensively caring for and managing TS patients.

Introduction: One of the most sensitive methods widely used to assess genotoxic effects on the human body in the early and long-term periods is the assessment of chromosomal aberrations. The study was focused on comparative analysis of the frequency of chromosomal aberrations in the blood lymphocytes of personnel (n = 20) of an atomic energy facility with a 15-year retrospective study. The aim of the study was to assess the dynamics of the frequency of chromosomal aberrations in the lymphocytes of the blood of atomic energy facility workers for 15 years. Materials and Methods: The assessment of the effects of ionizing radiation on the human body was performed by cytogenetic examination of the employees of the atomic energy facility (n = 20) exposed to ionizing radiation during their professional activities. The control group was composed of employees of the atomic energy facility, who underwent cytogenetic analysis in 2003. The study group was made up of the same employees of the atomic energy facility, who had been underwent a second cytogenetic study in 2018. Results and Discussion: A comparative analysis of the frequency of cytogenetic disorders in the blood lymphocytes of the atomic energy facility workers revealed differences between the studied groups in the frequency of dicentric chromosomes (p &lt; 0.05). In the study group, compared with the control group, an increase in the frequency of dicentric chromosomes was revealed (p = 0.0017). The frequencies of the other chromosomal aberrations types studied (chromosomal fragments, chromatid fragments, and ring chromosomes) did not differ between the groups compared. Conclusion: The results of this work make it possible to supplement and trace the understanding of the mutation process in the somatic cells of individuals who are exposed to ionizing radiation during their professional activities. The revealed statistical differences in the frequency of dicentric chromosomes deserve special attention, since the presence of this type of chromosomal aberrations is a marker of radiation exposure and allows us to verify the fact of exposure.

Complete genome sequence of Alteromonas marina OM2201, a marine bacterium degrading Ulva prolifera polysaccharides isolated from surface of the Yellow Sea.

BackgroundBacillus is used as a biological control agent in agricultural production. The main mechanisms responsible for its biocontrol activity encompass the generation of various antifungal active substances during life activities, competition, antagonism with pathogens, promotion of growth, and induction of plant resistance, enhancing the inhibition of pathogenic fungi. Bacillus has high biological control potential and has become a research hotspot.ResultsIt was found that strain KC14-1 had significant inhibitory effects on Fusarium fujikuroi, Rhizoclonia solani, Alternaria solani, Fusarium oxysporum, and Valsa mali. Based on morphological observations, physiological and biochemical determinations, and 16 S rRNA, gyrA, and gyrB gene sequencing, strain KC14-1 was identified as Bacillus subtilis. Whole genome sequencing results showed that the genome of strain KC14-1 was composed of a ring chromosome 3,908,079 bp in size, with a GC content of 43.82% and 3,895 coding genes. Anti-SMASH predicted that the genome of strain KC14-1 contained nine gene clusters that synthesised antibacterial substances. The homology between fengycin, bacillibactin, pulcherriminic acid, subtilosin A, and bacilysin was 100%.ConclusionThe biocontrol potential of Bacillus subtilis KC14-1 was determined through whole-genome analysis. Our study provides a solid foundation for developing and utilising this strain.