Large-scale copy number variants (CNVs) are structural alterations in the genome that involve the duplication or deletion of DNA segments, contributing to genetic diversity and playing a crucial role ...in the evolution and development of various diseases and disorders, as they can lead to the dosage imbalance of one or more genes. Massively parallel sequencing (MPS) has revolutionized the field of genetic analysis and contributed significantly to routine clinical diagnosis and screening. It offers a precise method for detecting CNVs with exceptional accuracy. In this context, a non-invasive prenatal test (NIPT) based on the sequencing of cell-free DNA (cfDNA) from pregnant women's plasma using a low-coverage whole genome MPS (WGS) approach represents a valuable source for population studies. Here, we analyzed genomic data of 12,732 pregnant women from the Slovak (9,230), Czech (1,583), and Hungarian (1,919) populations. We identified 5,062 CNVs ranging from 200 kbp and described their basic characteristics and differences between the subject populations. Our results suggest that re-analysis of sequencing data from routine WGS assays has the potential to obtain large-scale CNV population frequencies, which are not well known and may provide valuable information to support the classification and interpretation of this type of genetic variation. Furthermore, this could contribute to expanding knowledge about the central European genome without investing in additional laboratory work, as NIPTs are a relatively widely used screening method.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
The discovery of cell-free fetal DNA fragments in the maternal plasma initiated a novel testing method in prenatal care, called non-invasive prenatal screening (NIPS). One of the limitations of NIPS ...is the necessity for a sufficient proportion of fetal fragments in the analyzed circulating DNA mixture (fetal fraction), otherwise, the sample is uninterpretable. We present the effect of gestational age, maternal body mass index (BMI), and maternal age on the fetal fraction (FF) of the sample. We retrospectively analyzed data from 5543 pregnant women with a single male fetus who underwent NIPS from which 189 samples received a repeat testing due to an insufficient FF. We showed the relationship between the failure rate of the samples after the repeated analysis, the FF, and the gestational age at the first sampling. Next, we found that different maternal BMI categories affect the FF and thus the chance of an informative redraw. A better understanding of the factors affecting the FF will reduce the number of non-informative calls from repeated analyzes. In this study, we provide helpful information to clinicians on how to approach non-informative analyses.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
To study the detection limits of chromosomal microaberrations in non-invasive prenatal testing with aim for five target microdeletion syndromes, including DiGeorge, Prader-Willi/Angelman, 1p36, ...Cri-Du-Chat, and Wolf-Hirschhorn syndromes. We used known cases of pathogenic deletions from ISCA database to specifically define regions critical for the target syndromes. Our approach to detect microdeletions, from whole genome sequencing data, is based on sample normalization and read counting for individual bins. We performed both an in-silico study using artificially created data sets and a laboratory test on mixed DNA samples, with known microdeletions, to assess the sensitivity of prediction for varying fetal fractions, deletion lengths, and sequencing read counts. The in-silico study showed sensitivity of 79.3% for 10% fetal fraction with 20M read count, which further increased to 98.4% if we searched only for deletions longer than 3Mb. The test on laboratory-prepared mixed samples was in agreement with in-silico results, while we were able to correctly detect 24 out of 29 control samples. Our results suggest that it is possible to incorporate microaberration detection into basic NIPT as part of the offered screening/diagnostics procedure, however, accuracy and reliability depends on several specific factors.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
After the acute phase of COVID-19, some patients develop long COVID. This term is used for a variety of conditions with a complex, yet not fully elucidated etiology, likely including the prolonged ...persistence of the virus in the organism and progression to lung fibrosis. We present a unique autopsy case of a patient with severe COVID-19 with prolonged viral persistence who developed interstitial lung fibrosis complicated by a fatal combination of cytomegalovirus and Aspergillus infection. SARS-CoV-2 virus was detected at autopsy in the lungs more than two months after the acute infection, although tests from the nasopharynx were negative. Immune dysregulation after COVID-19 and the administration of corticoid therapy created favorable conditions for the cytomegalovirus and Aspergillus infection that were uncovered at autopsy. These pathogens may represent a risk for opportunistic infections, complicating not only the acute coronavirus infection but also long COVID, as was documented in the presented case.
Endometrial cancer belongs to the most common gynecologic cancer types globally, with increasing incidence. There are numerous ways of classifying different cases. The most recent decade has brought ...advances in molecular classification, which show more accurate prognostic factors and the possibility of personalised adjuvant treatment. In addition, diagnostic approaches lag behind these advances, with methods causing patients discomfort while lacking the reproducibility of tissue sampling for biopsy. Minimally invasive liquid biopsies could therefore represent an alternative screening and diagnostic approach in patients with endometrial cancer. The method could potentially detect molecular changes in this cancer type and identify patients at early stages. In this pilot study, we tested such a detection method based on circulating tumour DNA isolated from the peripheral blood plasma of 21 Slovak endometrial cancer patients. We successfully detected oncomutations in the circulating DNA of every single patient, although the prognostic value of the detected mutations failed to offer certainty. Furthermore, we detected changes associated with clonal hematopoiesis, including
mutations, which were present in the majority of circulating tumour DNA samples.
The aims of this study were to test the utility of benchtop NGS platforms for NIPT for trisomy 21 using previously published z score calculation methods and to optimize the sample preparation and ...data analysis with use of in silico and physical size selection methods.
Samples from 130 pregnant women were analyzed by whole genome sequencing on benchtop NGS systems Ion Torrent PGM and MiSeq. The targeted yield of 3 million raw reads on each platform was used for z score calculation. The impact of in silico and physical size selection on analytical performance of the test was studied.
Using a z score value of 3 as the cut-off, 98.11%-100% (104-106/106) specificity and 100% (24/24) sensitivity and 99.06%-100% (105-106/106) specificity and 100% (24/24) sensitivity were observed for Ion Torrent PGM and MiSeq, respectively. After in silico based size selection both platforms reached 100% specificity and sensitivity. Following the physical size selection z scores of tested trisomic samples increased significantly--p = 0.0141 and p = 0.025 for Ion Torrent PGM and MiSeq, respectively.
Noninvasive prenatal testing for chromosome 21 trisomy with the utilization of benchtop NGS systems led to results equivalent to previously published studies performed on high-to-ultrahigh throughput NGS systems. The in silico size selection led to higher specificity of the test. Physical size selection performed on isolated DNA led to significant increase in z scores. The observed results could represent a basis for increasing of cost effectiveness of the test and thus help with its penetration worldwide.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
During the recent pandemics of COVID-19, sequencing technics became a powerful tool for gaining information about the SARS-CoV-2 virus and using this knowledge to our advantage. Thanks to this ...advantage, scientists all over the world were able to search for emerging variations, watching the virus evolve in real time. Assembly of the virus genomes is a crucial part of obtaining this kind of useful information. In our study, we sequenced 79 samples from nasopharyngeal swabs of COVID-19 patients. Positivity to disease was evaluated using RT-qPCR. In this work, we described the relationship between RT-qPCR Ct value and genome construction success (plus genome lineage assignment). The specific value of this study is that this relationship was described for data from metatranscriptomic sequencing of human tissue, while there was no step of viral RNA isolation (usual for genome assembly procedure). RT-qPCR Ct value and assembly quality metric NG50 were correlated. We observed that the RT-qPCR Ct value threshold of the certain success of genome assembly (Ct value < 25) and certain failure (Ct value > 30) could be drawn, while results varied for values between (with completed, completed with lower quality, and failed assemblies).
•Syndromic cases can show clinical features extending beyond those reported in the current literature.•Multilocus pathogenic variants can explain the apparent phenotypic expansion in some syndromic ...patients.•Patients with multiple genetic diagnoses are not so rare.•The clinical picture of thrombocytopenia absent radius syndrome seems to be expanded by hypospadias in our proband.•The proband received a dual genetic diagnosis of thrombocytopenia absent radius syndrome and thyroid dyshormonogenesis type 6.
Rare genetic diseases and syndromes may appear with unique features in some patients. In genetically-solved cases, this situation indicates a phenotypic expansion of the syndrome with additional features (i.e. the disease-associated gene gives rise to unusual clinical presentation). However, this situation can also hide a multilocus pathogenic variation that cannot be solved genetically except by a massive sequencing approach, such as exome sequencing. Here we describe the case of a child with bilateral radial aplasia, transient thrombocytopenia and anemia, cow's milk intolerance, hypospadias, facial dysmorphism, mild hypothyroidism and umbilical and inguinal hernia.
Bilaterally absent radius, presence of thumbs and low platelet count are pathognomonic of thrombocytopenia absent radius (TAR) syndrome, but the child also showed other features beyond those reported in the literature. Since various diseases resembling the proband’s phenotype required differential diagnosis, clinical exome sequencing was performed. The results showed compound heterozygous mutations in the RBM8A gene, confirming the suspicion of TAR syndrome. A truncating heterozygous variant in the DUOX2 gene, known to be associated with transient thyroid dyshormonogenesis type 6 (TDH6), was also detected and may explain the proband's mild hypothyroidism.
Since its outbreak in late 2019, the SARS-CoV-2 virus has been the main subject of interest for a number of studies. Clinical manifestations are ranging from asymptomatic to mild and severe. Major ...risk factors for developing severe COVID-19 are age and comorbidities, although younger people suffer from severe COVID-19 as well. One of the explanations for why can be the composition of respiratory tract microbiota. In this article, we review studies linking respiratory tract microbiome and its changes during COVID-19 infection. The respiratory tract microbiome helps shape immunity and it is assumed that it can affect the outcome of several viral infections. Several studies show differences in the microbial composition of the respiratory tract between COVID-19 patients and healthy individuals. The diversity of the respiratory tract microbiome is reduced with increasing severity of COVID-19.
Non-invasive prenatal testing (NIPT) has become a routine practice in screening for common aneuploidies of chromosomes 21, 18, and 13 and gonosomes X and Y in fetuses worldwide since 2015 and has ...even expanded to include smaller subchromosomal events. In fact, the fetal fraction represents only a small proportion of cell-free DNA on a predominant background of maternal DNA. Unlike fetal findings that have to be confirmed using invasive testing, it has been well documented that NIPT provides information on maternal mosaicism, occult malignancies, and hidden health conditions due to copy number variations (CNVs) with diagnostic resolution. Although large duplications or deletions associated with certain medical conditions or syndromes are usually well recognized and easy to interpret, very little is known about small, relatively common copy number variations on the order of a few hundred kilobases and their potential impact on human health. We analyzed data from 6422 NIPT patient samples with a CNV detection resolution of 200 kb for the maternal genome and identified 942 distinct CNVs; 328 occurred repeatedly. We defined them as multiple occurring variants (MOVs). We scrutinized the most common ones, compared them with frequencies in the gnomAD SVs v2.1, dbVar, and DGV population databases, and analyzed them with an emphasis on genomic content and potential association with specific phenotypes.
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