BACKGROUND: Structural variations play an important role in bacterial genomes. They can mediate genome adaptation quickly in response to the external environment and thus can also play a role in antibiotic resistance. The detection of structural variations in bacteria is challenging, and the recognition of even small rearrangements can be important. Even though most detection tools are aimed at and benchmarked on eukaryotic genomes, they can also be used on prokaryotic genomes. The key features of detection are the ability to detect small rearrangements and support haploid genomes. Because of the limiting performance of a single detection tool, combining the detection abilities of multiple tools can lead to more robust results. There are already available workflows for structural variation detection for long-reads technologies and for the detection of single-nucleotide variation and indels, both aimed at bacteria. Yet we are unaware of structural variations detection workflows for the short-reads sequencing platform. Motivated by this gap we created our workflow. Further, we were interested in increasing the detection performance and providing more robust results. RESULTS: We developed an open-source bioinformatics pipeline, ProcaryaSV, for the detection of structural variations in bacterial isolates from paired-end short sequencing reads. Multiple tools, starting with quality control and trimming of sequencing data, alignment to the reference genome, and multiple structural variation detection tools, are integrated. All the partial results are then processed and merged with an in-house merging algorithm. Compared with a single detection approach, ProcaryaSV has improved detection performance and is a reproducible easy-to-use tool. CONCLUSIONS: The ProcaryaSV pipeline provides an integrative approach to structural variation detection from paired-end next-generation sequencing of bacterial samples. It can be easily installed and used on Linux machines. It is publicly available on GitHub at https://github.com/robinjugas/ProcaryaSV .

• Klíčová slova
• Bacteria, CNV, Copy number variation, Pipeline, SV, Structural variation,
• MeSH
• Bacteria genetika   MeSH
• genom bakteriální * MeSH
• sekvenční analýza DNA metody   MeSH
• software * MeSH
• vysoce účinné nukleotidové sekvenování * metody   MeSH
• Publikační typ
• časopisecké články MeSH

Hepatocellular carcinoma (HCC) mainly stems from liver cirrhosis and its genetic predisposition is believed to be rare. However, two recent studies describe pathogenic/likely pathogenic germline variants (PV) in cancer-predisposition genes (CPG). As the risk of de novo tumors might be increased in PV carriers, especially in immunosuppressed patients after a liver transplantation, we analyzed the prevalence of germline CPG variants in HCC patients considered for liver transplantation. Using the panel NGS targeting 226 CPGs, we analyzed germline DNA from 334 Czech HCC patients and 1662 population-matched controls. We identified 48 PVs in 35 genes in 47/334 patients (14.1%). However, only 7/334 (2.1%) patients carried a PV in an established CPG (PMS2, 4×NBN, FH or RET). Only the PV carriers in two MRN complex genes (NBN and RAD50) were significantly more frequent among patients over controls. We found no differences in clinicopathological characteristics between carriers and non-carriers. Our study indicated that the genetic component of HCC is rare. The HCC diagnosis itself does not meet criteria for routine germline CPG genetic testing. However, a low proportion of PV carriers may benefit from a tailored follow-up or targeted therapy and germline testing could be considered in liver transplant recipients.

• Klíčová slova
• MRN complex, genetic predisposition, germline mutation, hepatocellular carcinoma, liver cirrhosis, liver transplantation, panel sequencing,
• Publikační typ
• časopisecké články MeSH

Understanding the genetic basis of reproductive isolation is a central issue in the study of speciation. Structural variants (SVs); that is, structural changes in DNA, including inversions, translocations, insertions, deletions, and duplications, are common in a broad range of organisms and have been hypothesized to play a central role in speciation. Recent advances in molecular and statistical methods have identified structural variants, especially inversions, underlying ecologically important traits; thus, suggesting these mutations contribute to adaptation. However, the contribution of structural variants to reproductive isolation between species-and the underlying mechanism by which structural variants most often contribute to speciation-remain unclear. Here, we review (i) different mechanisms by which structural variants can generate or maintain reproductive isolation; (ii) patterns expected with these different mechanisms; and (iii) relevant empirical examples of each. We also summarize the available sequencing and bioinformatic methods to detect structural variants. Lastly, we suggest empirical approaches and new research directions to help obtain a more complete assessment of the role of structural variants in speciation.

• Klíčová slova
• hybridization, reproductive isolation, suppressed recombination,
• MeSH
• biologická evoluce MeSH
• druhová specificita * MeSH
• fenotyp MeSH
• fyziologická adaptace MeSH
• lidé MeSH
• molekulární evoluce MeSH
• reprodukční izolace MeSH
• strukturální variace genomu genetika   MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• přehledy MeSH
• Research Support, U.S. Gov't, Non-P.H.S. MeSH

Hearing loss is a genetically heterogeneous sensory defect, and the frequent causes are biallelic pathogenic variants in the GJB2 gene. However, patients carrying only one heterozygous pathogenic (monoallelic) GJB2 variant represent a long-lasting diagnostic problem. Interestingly, previous results showed that individuals with a heterozygous pathogenic GJB2 variant are two times more prevalent among those with hearing loss compared to normal-hearing individuals. This excess among patients led us to hypothesize that there could be another pathogenic variant in the GJB2 region/DFNB1 locus. A hitherto undiscovered variant could, in part, explain the cause of hearing loss in patients and would mean reclassifying them as patients with GJB2 biallelic pathogenic variants. In order to detect an unknown causal variant, we examined 28 patients using NGS with probes that continuously cover the 0.4 Mb in the DFNB1 region. An additional 49 patients were examined by WES to uncover only carriers. We did not reveal a second pathogenic variant in the DFNB1 region. However, in 19% of the WES-examined patients, the cause of hearing loss was found to be in genes other than the GJB2. We present evidence to show that a substantial number of patients are carriers of the GJB2 pathogenic variant, albeit only by chance.

• Klíčová slova
• DFNB1 region, GJB2 monoallelic variant, hearing loss, next generation sequencing,
• MeSH
• frekvence genu MeSH
• heterozygot MeSH
• konexin 26 genetika   MeSH
• lidé MeSH
• mutace MeSH
• percepční nedoslýchavost genetika   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• GJB2 protein, human MeSH Prohlížeč
• konexin 26 MeSH

BACKGROUND: Oncopanel genomic testing, which identifies important somatic variants, is increasingly common in medical practice and especially in clinical trials. Currently, there is a paucity of reliable genomic reference samples having a suitably large number of pre-identified variants for properly assessing oncopanel assay analytical quality and performance. The FDA-led Sequencing and Quality Control Phase 2 (SEQC2) consortium analyze ten diverse cancer cell lines individually and their pool, termed Sample A, to develop a reference sample with suitably large numbers of coding positions with known (variant) positives and negatives for properly evaluating oncopanel analytical performance. RESULTS: In reference Sample A, we identify more than 40,000 variants down to 1% allele frequency with more than 25,000 variants having less than 20% allele frequency with 1653 variants in COSMIC-related genes. This is 5-100× more than existing commercially available samples. We also identify an unprecedented number of negative positions in coding regions, allowing statistical rigor in assessing limit-of-detection, sensitivity, and precision. Over 300 loci are randomly selected and independently verified via droplet digital PCR with 100% concordance. Agilent normal reference Sample B can be admixed with Sample A to create new samples with a similar number of known variants at much lower allele frequency than what exists in Sample A natively, including known variants having allele frequency of 0.02%, a range suitable for assessing liquid biopsy panels. CONCLUSION: These new reference samples and their admixtures provide superior capability for performing oncopanel quality control, analytical accuracy, and validation for small to large oncopanels and liquid biopsy assays.

• MeSH
• alely * MeSH
• frekvence genu * MeSH
• genetická heterogenita MeSH
• genetická variace * MeSH
• genetické testování metody   normy   MeSH
• genomika metody   normy   MeSH
• lidé MeSH
• nádorové biomarkery * MeSH
• nádorové buněčné linie MeSH
• nádory diagnóza   genetika   MeSH
• průběh práce MeSH
• variabilita počtu kopií segmentů DNA MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• nádorové biomarkery * MeSH

Although gene duplications provide genetic backup and allow genomic changes under relaxed selection, they may potentially limit gene flow. When different copies of a duplicated gene are pseudofunctionalized in different genotypes, genetic incompatibilities can arise in their hybrid offspring. Although such cases have been reported after manual crosses, it remains unclear whether they occur in nature and how they affect natural populations. Here, we identified four duplicated-gene based incompatibilities including one previously not reported within an artificial Arabidopsis intercross population. Unexpectedly, however, for each of the genetic incompatibilities we also identified the incompatible alleles in natural populations based on the genomes of 1,135 Arabidopsis accessions published by the 1001 Genomes Project. Using the presence of incompatible allele combinations as phenotypes for GWAS, we mapped genomic regions that included additional gene copies which likely rescue the genetic incompatibility. Reconstructing the geographic origins and evolutionary trajectories of the individual alleles suggested that incompatible alleles frequently coexist, even in geographically closed regions, and that their effects can be overcome by additional gene copies collectively shaping the evolutionary dynamics of duplicated genes during population history.

• Klíčová slova
• HPA, TIM22, duplicated gene, genetic incompatibility, genome-wide association study, loss of function,
• MeSH
• alely MeSH
• Arabidopsis genetika   MeSH
• duplikace genu * MeSH
• fylogeografie MeSH
• reprodukční izolace * MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

Tumor protein p53 (TP53) is the most frequently mutated gene in cancer1,2. In patients with myelodysplastic syndromes (MDS), TP53 mutations are associated with high-risk disease3,4, rapid transformation to acute myeloid leukemia (AML)5, resistance to conventional therapies6-8 and dismal outcomes9. Consistent with the tumor-suppressive role of TP53, patients harbor both mono- and biallelic mutations10. However, the biological and clinical implications of TP53 allelic state have not been fully investigated in MDS or any other cancer type. We analyzed 3,324 patients with MDS for TP53 mutations and allelic imbalances and delineated two subsets of patients with distinct phenotypes and outcomes. One-third of TP53-mutated patients had monoallelic mutations whereas two-thirds had multiple hits (multi-hit) consistent with biallelic targeting. Established associations with complex karyotype, few co-occurring mutations, high-risk presentation and poor outcomes were specific to multi-hit patients only. TP53 multi-hit state predicted risk of death and leukemic transformation independently of the Revised International Prognostic Scoring System (IPSS-R)11. Surprisingly, monoallelic patients did not differ from TP53 wild-type patients in outcomes and response to therapy. This study shows that consideration of TP53 allelic state is critical for diagnostic and prognostic precision in MDS as well as in future correlative studies of treatment response.

• MeSH
• alely MeSH
• analýza přežití MeSH
• fenotyp MeSH
• frekvence genu MeSH
• kohortové studie MeSH
• lidé MeSH
• mutace MeSH
• mutační analýza DNA MeSH
• myelodysplastické syndromy diagnóza   genetika   mortalita   terapie   MeSH
• nádorový supresorový protein p53 genetika   MeSH
• nestabilita genomu genetika   MeSH
• prognóza MeSH
• variabilita počtu kopií segmentů DNA genetika   MeSH
• výsledek terapie MeSH
• ztráta heterozygozity genetika   MeSH
• Check Tag
• lidé MeSH
• mužské pohlaví MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• nádorový supresorový protein p53 MeSH
• TP53 protein, human MeSH Prohlížeč

We performed comprehensive molecular analysis of five cases of metastasizing uveal malignant melanoma (UM) (fresh-frozen samples) with an NGS panel of 73 genes. A likely pathogenic germline TP53 mutation c.760A > G (p.I254V) was found in two tumor samples and matched nontumor tissue. In three cases, pathogenic BAP1 mutation was detected together with germline missense variants of uncertain significance in ATM. All cases carried recurrent activating GNAQ or GNA11 mutation. Moreover, we analyzed samples from another 16 patients with primary UM by direct Sanger sequencing focusing only on TP53 coding region. No other germline TP53 mutation was detected in these samples. Germline TP53 mutation, usually associated with Li-Fraumeni syndrome, is a rare event in UM. To the best of our knowledge, only one family with germline TP53 mutation has previously been described. In our study, we detected TP53 mutation in two patients without known family relationship. The identification of germline aberrations in TP53 or BAP1 is important to identify patients with Li-Fraumeni syndrome or BAP1 cancer syndrome, which is also crucial for proper genetic counseling.

• MeSH
• ATM protein genetika   MeSH
• dospělí MeSH
• genetická predispozice k nemoci MeSH
• lidé středního věku MeSH
• lidé MeSH
• melanom genetika   patologie   MeSH
• míra přežití MeSH
• mladý dospělý MeSH
• mutační analýza DNA MeSH
• nádorové supresorové proteiny genetika   MeSH
• nádorový supresorový protein p53 genetika   MeSH
• nádory jater genetika   sekundární   MeSH
• nádory uvey genetika   patologie   MeSH
• prognóza MeSH
• senioři MeSH
• thiolesterasa ubikvitinu genetika   MeSH
• uveální melanom MeSH
• zárodečné mutace * MeSH
• Check Tag
• dospělí MeSH
• lidé středního věku MeSH
• lidé MeSH
• mladý dospělý MeSH
• mužské pohlaví MeSH
• senioři MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• ATM protein, human MeSH Prohlížeč
• ATM protein MeSH
• BAP1 protein, human MeSH Prohlížeč
• nádorové supresorové proteiny MeSH
• nádorový supresorový protein p53 MeSH
• thiolesterasa ubikvitinu MeSH
• TP53 protein, human MeSH Prohlížeč

BACKGROUND: Carriers of mutations in hereditary cancer predisposition genes represent a small but clinically important subgroup of oncology patients. The identification of causal germline mutations determines follow-up management, treatment options and genetic counselling in patients' families. Targeted next-generation sequencing-based analyses using cancer-specific panels in high-risk individuals have been rapidly adopted by diagnostic laboratories. While the use of diagnosis-specific panels is straightforward in typical cases, individuals with unusual phenotypes from families with overlapping criteria require multiple panel testing. Moreover, narrow gene panels are limited by our currently incomplete knowledge about possible genetic dispositions. METHODS: We have designed a multi-gene panel called CZECANCA (CZEch CAncer paNel for Clinical Application) for a sequencing analysis of 219 cancer-susceptibility and candidate predisposition genes associated with frequent hereditary cancers. RESULTS: The bioanalytical and bioinformatics pipeline was validated on a set of internal and commercially available DNA controls showing high coverage uniformity, sensitivity, specificity and accuracy. The panel demonstrates a reliable detection of both single nucleotide and copy number variants. Inter-laboratory, intra- and inter-run replicates confirmed the robustness of our approach. CONCLUSION: The objective of CZECANCA is a nationwide consolidation of cancer-predisposition genetic testing across various clinical indications with savings in costs, human labor and turnaround time. Moreover, the unified diagnostics will enable the integration and analysis of genotypes with associated phenotypes in a national database improving the clinical interpretation of variants.

• MeSH
• dědičné nádorové syndromy genetika   MeSH
• genetická predispozice k nemoci MeSH
• genetické asociační studie MeSH
• genetické testování MeSH
• lidé MeSH
• mutace INDEL MeSH
• mutace MeSH
• nádorové biomarkery * MeSH
• reprodukovatelnost výsledků MeSH
• senzitivita a specificita MeSH
• variabilita počtu kopií segmentů DNA MeSH
• výpočetní biologie metody   MeSH
• vysoce účinné nukleotidové sekvenování * metody   normy   MeSH
• Check Tag
• lidé MeSH
• mužské pohlaví MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• nádorové biomarkery * MeSH

The ETV6-RUNX1 fusion gene, found in 25% of childhood acute lymphoblastic leukemia (ALL) cases, is acquired in utero but requires additional somatic mutations for overt leukemia. We used exome and low-coverage whole-genome sequencing to characterize secondary events associated with leukemic transformation. RAG-mediated deletions emerge as the dominant mutational process, characterized by recombination signal sequence motifs near breakpoints, incorporation of non-templated sequence at junctions, ∼30-fold enrichment at promoters and enhancers of genes actively transcribed in B cell development and an unexpectedly high ratio of recurrent to non-recurrent structural variants. Single-cell tracking shows that this mechanism is active throughout leukemic evolution, with evidence of localized clustering and reiterated deletions. Integration of data on point mutations and rearrangements identifies ATF7IP and MGA as two new tumor-suppressor genes in ALL. Thus, a remarkably parsimonious mutational process transforms ETV6-RUNX1-positive lymphoblasts, targeting the promoters, enhancers and first exons of genes that normally regulate B cell differentiation.

• MeSH
• fúzní onkogenní proteiny genetika   MeSH
• genetická variace * MeSH
• genová knihovna MeSH
• genová přestavba genetika   MeSH
• homeodoménové proteiny genetika   MeSH
• lidé MeSH
• molekulární sekvence - údaje MeSH
• pre-B-buněčná leukemie genetika   MeSH
• protein PEBP2A2 genetika   MeSH
• regulace genové exprese u nádorů genetika   MeSH
• rekombinace genetická genetika   MeSH
• represorové proteiny MeSH
• sekvence nukleotidů MeSH
• sekvenční analýza DNA MeSH
• sekvenční delece genetika   MeSH
• transkripční faktory bHLH genetika   MeSH
• transkripční faktory genetika   MeSH
• tumor supresorové geny MeSH
• V(D)J rekombinace genetika   MeSH
• variabilita počtu kopií segmentů DNA genetika   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• ATF7IP protein, human MeSH Prohlížeč
• fúzní onkogenní proteiny MeSH
• homeodoménové proteiny MeSH
• MGA protein, human MeSH Prohlížeč
• protein PEBP2A2 MeSH
• RAG-1 protein MeSH Prohlížeč
• represorové proteiny MeSH
• TEL-AML1 fusion protein MeSH Prohlížeč
• transkripční faktory bHLH MeSH
• transkripční faktory MeSH