Genetic Characterization Research Articles

Clinical and Genetic Characterization of a Cohort of Brazilian Patients With Congenital Ataxia.

Congenital ataxias are rare hereditary disorders characterized by hypotonia and developmental motor delay in the first few months of life, followed by cerebellar ataxia in early childhood. The course of the disease is predominantly nonprogressive, and many patients are incorrectly diagnosed with cerebral palsy. Despite significant advancements in next-generation sequencing in the past few decades, a specific genetic diagnosis is seldom obtained in cases of congenital ataxia. The aim of the study was to analyze the clinical, radiologic, and genetic features of a cohort of Brazilian patients with congenital ataxia. Thirty patients with a clinical diagnosis of congenital ataxia were enrolled in this study. Clinical and demographic features and neuroimaging studies were analyzed. Genetic testing (whole-exome sequencing) was also performed. A heterogeneous pattern of genetic variants was detected. Eighteen genes were involved: ALDH5A1, BRF1, CACNA1A CACNA1G, CC2D2A, CWF19L1, EXOSC3, ITPR1, KIF1A, MME, PEX10, SCN2A, SNX14, SPTBN2, STXBP1, TMEM240, THG1L, and TUBB4A. Pathogenic/likely pathogenic variants involving 11 genes (ALDH5A1, CACNA1A, EXOSC3, MME, ITPR1, KIF1A, STXBP1, SNX14, SPTBN2, TMEM240, and TUBB4A) were identified in 46.7% of patients. Variants of uncertain significance involving 8 genes were detected in 33.3% of patients. Congenital ataxias were characterized by a broad phenotype. A genetic diagnosis was more often obtained in patients with cerebellar-plus syndrome than in patients with a pure cerebellar syndrome. This study re-emphasizes the genetic heterogeneity of congenital ataxias and the absence of a clear phenotype-genotype relationship. A specific genetic diagnosis was established in 46.7% of patients. Autosomal dominant, associated with sporadic cases, was recognized as an important genetic inheritance. The results of this analysis highlight the value of whole-exome sequencing as an efficient screening tool in patients with congenital ataxia.

Genetic Characterization and Population Structure of Drug-Resistant Mycobacterium tuberculosis Isolated from Brazilian Patients Using Whole-Genome Sequencing

The present study aimed to determine the genetic diversity of isolates of Mycobacterium tuberculosis (Mtb) from presumed drug-resistant tuberculosis patients from several states of Brazil. The isolates had been submitted to conventional drug susceptibility testing for first- and second-line drugs. Multidrug-resistant (MDR-TB) (54.8%) was the most frequent phenotypic resistance profile, in addition to an important high frequency of pre-extensive resistance (p-XDR-TB) (9.2%). Using whole-genome sequencing (WGS), we characterized 298 Mtb isolates from Brazil. Besides the analysis of genotype distribution and possible correlations between molecular and clinical data, we determined the performance of an in-house WGS pipeline with other online pipelines for Mtb lineages and drug resistance profile definitions. Sub-lineage 4.3 (52%) was the most frequent genotype, and the genomic approach revealed a p-XDR-TB level of 22.5%. We detected twenty novel mutations in three resistance genes, and six of these were observed in eight phenotypically resistant isolates. A cluster analysis of 170 isolates showed that 43.5% of the TB patients belonged to 24 genomic clusters, suggesting considerable ongoing transmission of DR-TB, including two interstate transmissions. The in-house WGS pipeline showed the best overall performance in drug resistance prediction, presenting the best accuracy values for five of the nine drugs tested. Significant associations were observed between suffering from fatal disease and genotypic p-XDR-TB (p = 0.03) and either phenotypic (p = 0.006) or genotypic (p = 0.0007) ethambutol resistance. The use of WGS analysis improved our understanding of the population structure of MTBC in Brazil and the genetic and clinical data correlations and demonstrated its utility for surveillance efforts regarding the spread of DR-TB, hopefully helping to avoid the emergence of even more resistant strains and to reduce TB incidence and mortality rates.

Genetic Characterization of Endangered Sterlet (Acipenser ruthenus, Linnaeus 1758) Gene Bank Broodstock, Natural and Cultured Populations in Hungary

The sterlet (Acipenser ruthenus) is the smallest-bodied endangered species among the six native sturgeon species of the Danube River, and self-sustaining populations still inhabit the Hungarian section of the Danube River and its largest tributary, the Tisza River. Their populations are drastically decreasing; however, they still have natural reproduction in these habitats. For the genetic conservation of the species, an ex situ gene bank is maintained in Hungary. The present study aimed to analyze the genetic resources of a gene bank with a near 40-year history and to compare it with natural populations and farmed stocks. Twelve microsatellites were used for population genetics analyses and individual genotyping of 268 specimens from two natural habitats (Danube and Tisza Rivers) and three captive stocks (a gene bank broodstock and two farms). Microsatellites revealed similar patterns among wild populations and gene bank stocks and did not show genetic differentiation (FST: 0.016–0.017) among them. These results confirmed that the gene bank broodstock properly represents the genetic background of the Danube and Tisza populations and is suitable as a source of breeding materials for the restocking programs. Negative trends were detected in the farmed stocks, reflected in reduced polymorphism at a few loci. The results of the principal component analyses indicate the farm stocks’ separation from the wild and gene bank stocks. The present genetic characterization study reveals a valuable captive stock of the endangered sterlet populations and provides unique information about the genetic similarities and differences among farms and wild stocks in Hungary. Our results provide information that contributes to preserving the genetic structure and variability in sterlet populations and supports the management of gene bank broodstock—avoiding inbreeding and preserving the unique genetic background of the Carpathian basin.

A systematic review on the culture methods and applications of 3D tumoroids for cancer research and personalized medicine.

Cancer is a highly heterogeneous disease, and thus treatment responses vary greatly between patients. To improve therapy efficacy and outcome for cancer patients, more representative and patient-specific preclinical models are needed. Organoids and tumoroids are 3D cell culture models that typically retain the genetic and epigenetic characteristics, as well as the morphology, of their tissue of origin. Thus, they can be used to understand the underlying mechanisms of cancer initiation, progression, and metastasis in a more physiological setting. Additionally, co-culture methods of tumoroids and cancer-associated cells can help to understand the interplay between a tumor and its tumor microenvironment. In recent years, tumoroids have already helped to refine treatments and to identify new targets for cancer therapy. Advanced culturing systems such as chip-based fluidic devices and bioprinting methods in combination with tumoroids have been used for high-throughput applications for personalized medicine. Even though organoid and tumoroid models are complex in vitro systems, validation of results in vivo is still the common practice. Here, we describe how both animal- and human-derived tumoroids have helped to identify novel vulnerabilities for cancer treatment in recent years, and how they are currently used for precision medicine.

Disease spectrum, prevalence, genetic characteristics of inborn errors of metabolism in 21,840 hospitalized infants in Chongqing, China, 2017-2022

Inborn errors of metabolism (IEMs) are uncommon. Although some studies have explored the distribution and characteristics of IEMs in newborns, the impact of these disorders on hospitalized newborns remains unclear. In this study, we gathered data from 21,840 newborn patients admitted for various medical conditions at the Children’s Hospital of Chongqing Medical University from January 2017 and December 2022. Liquid chromatography-tandem mass spectrometry (LC-MS/MS), gas chromatography-mass spectrometry (GC-MS/MS), and genetic analysis were used to elucidate the disease spectrum, incidence rate, and genetic characteristics of IEMs in hospitalized newborns. The results revealed that the incidence of IEMs in hospitalized newborns was 1/377 (58/21,840), with a higher incidence in full-term infants (1/428) than in premature infants (1/3,120). Among the diagnosed genetic metabolic diseases, organic acid metabolism disorders (1/662), amino acid metabolism disorders (1/950), and fatty acid oxidation disorders (1/10,920) were the most prevalent. Methylmalonic acidemia (MMA), especially the isolated form, emerged as the most common IEM, while neonatal intrahepatic cholestasis caused by citrin deficiency (NICCD) and ornithine transcarbamylase deficiency (OTCD) were prevalent in premature infants. Of the 58 confirmed cases of IEMs, 72 variants were identified, of which 31.94% (23/72) had not been reported previously. This study contributes to understanding the incidence and clinical features of IEMs in hospitalized newborns, offering more efficient strategies for screening and diagnosing these disorders.

The First Genetic Characterization of the SPRN Gene in Pekin Ducks (Anas platyrhynchos domesticus)

Prion diseases are fatal neurodegenerative disorders characterized by an accumulation of misfolded prion protein (PrPSc) in brain tissues. The shadow of prion protein (Sho) encoded by the shadow of prion protein gene (SPRN) is involved in prion disease progress. The interaction between Sho and PrP accelerates the PrPSc conversion rate while the SPRN gene polymorphisms have been associated with prion disease susceptibility in several species. Until now, the SPRN gene has not been investigated in ducks. We identified the duck SPRN gene sequence and investigated the genetic polymorphisms of 184 Pekin ducks. We compared the duck SPRN nucleotide sequence and the duck Sho protein amino acid sequence with those of several other species. Finally, we predicted the duck Sho protein structure and the effects of non-synonymous single nucleotide polymorphisms (SNPs) using computational programs. We were the first to report the Pekin duck SPRN gene sequence. The duck Sho protein sequence showed 100% identity compared with the chicken Sho protein sequence. We found 27 novel SNPs in the duck SPRN gene. Four amino acid substitutions were predicted to affect the hydrogen bond distribution in the duck Sho protein structure. Although MutPred2 and SNPs&GO predicted that all non-synonymous polymorphisms were neutral or benign, SIFT predicted that four variants, A22T, G49D, A68T, and M105I, were deleterious. To the best of our knowledge, this is the first report about the genetic and structural characteristics of the duck SPRN gene.

Integrative immunophenotypic and genetic characterization of acute myeloid leukemia with CBFB rearrangement.

We sought to characterize the immunophenotype of acute myeloid leukemia (AML) with CBFB rearrangement and correlate the results with cytogenetic and molecular data. Sixty-one cases of AML with CBFB rearrangement were evaluated. The sample population consisted of 33 men and 28 women, with a median age of 49 years. Flow cytometry immunophenotypic analysis showed that myeloblasts were positive for CD34 and CD117 in all cases, and myeloperoxidase was positive in 52 of 55 (95%) cases. The most common abnormalities included decreased CD38 in 90%, increased CD13 in 85%, increased CD123 in 84%, and decreased HLA-DR in 84% of cases. Monocytes were increased, with a mature immunophenotype, and accounted for 23.7% of total cells. Among 60 cases with available karyotype, inv(16)(p13.1q22) was most common in 50 (83%) cases, followed by t(16;16) (p13.1;q22) in 6 (10%). Type A CBFB::MYH11 transcript was most common, detected in 84% of cases. Mutational analysis showed mutations of NRAS in 37%, FLT3 in 25%, and KIT in 24% of cases. Comparing cases with type A vs non-type A transcripts, blasts in type A cases more frequently exhibited CD64 positivity and increased CD13 levels while showing a lower frequency of CD7 and CD56 expression. Trisomy 22 and mutations in KIT, NF1, and TET2 were identified only in cases with type A transcript. Myeloblasts of AML with CBFB rearrangement are positive for CD34, CD117, and myeloperoxidase. These neoplasms most frequently carry inv(16)(p13.1q22) and type A fusion transcript. NRAS mutation was the most common mutation. Some immunophenotypic and genetic correlations occurred with different types of transcripts.

Characteristics, aetiology and implications for management of multiple primary renal tumours: a systematic review.

In a subset of patients with renal tumours, multiple primary lesions may occur. Predisposition to multiple primary renal tumours (MPRT) is a well-recognised feature of some inherited renal cancer syndromes. The diagnosis of MPRT should therefore provoke a thorough assessment for clinical and genetic evidence of disorders associated with predisposition to renal tumourigenesis. To better define the clinical and genetic characteristics of MPRT, a systematic literature review was performed for publications up to 3 April 2024. A total of 7689 patients from 467 articles were identified with MPRT. Compared to all patients with renal cell carcinoma (RCC), patients with MPRT were more likely to be male (71.8% versus 63%) and have an earlier age at diagnosis (<46 years, 32.4% versus 19%). In 61.1% of cases MPRT were synchronous. The proportion of cases with similar histology and the proportion of cases with multiple papillary renal cell carcinoma (RCC) (16.1%) were higher than expected. In total, 14.9% of patients with MPRT had a family history of cancer or were diagnosed with a hereditary RCC associated syndrome with von Hippel-Lindau (VHL) disease being the most common one (69.7%), followed by Birt-Hogg-Dubé (BHD) syndrome (14.2%). Individuals with a known or likely genetic cause were, on average, younger (43.9 years versus 57.1 years). In rare cases intrarenal metastatic RCC can phenocopy MPRT. We review potential genetic causes of MPRT and their implications for management, suggest an approach to genetic testing for individuals presenting with MPRT and considerations in cases in which routine germline genetic testing does not provide a diagnosis.

Progress of circulating tumor DNA methylation for gastric cancer screening and management

Circulating tumor DNA (ctDNA) is cell-free DNA released by tumors or circulating tumor cells, containing abundant tumor-specific information that can serve as biomarkers for cancer early screening, monitoring, prognosis, and prediction of treatment response. This is particularly attractive in the field of gastric cancer, where high-quality screening, monitoring, and prediction methods are currently lacking. Gastric cancer exhibits significant tumor heterogeneity, with large differences in genetic and epigenetic characteristics among different subgroups. Methylated ctDNA has high sensitivity and specificity, which can help clarify tumor genotyping and facilitate the formulation of precise diagnostic and therapeutic strategies. Furthermore, numerous studies have confirmed the unique advantages of methylated DNA in predicting treatment response, adjuvant therapy, and drug resistance assessment, which may be used in the future to enhance the efficacy of chemotherapy regimens and improve patient chemotherapeutic response, and even treat multidrug resistance. However, there are several challenges associated with methylated ctDNA, such as low sensitivity and specificity at single-target sites, limited association between some gastric cancer subtypes and ctDNA, off-target risks, and the lack of large-scale and high-quality clinical research evidence. This review mainly summarizes current research on the methylation status of ctDNA in gastric cancer and connects these findings to early screening, recurrence monitoring, and potential treatment opportunities for gastric cancer. With advances in technology and the deepening of interdisciplinary research, ctDNA detection will reveal more disease information and become an essential foundation for gastric cancer research and precision medicine treatment.

Genetic profiles of oligometastatic non-small cell lung cancer and corresponding brain metastases.

In patients with oligometastatic non-small cell lung cancer, systemic therapy in combination with local ablative treatment of the primary tumor and all metastatic sites is associated with improved prognosis. For patient selection and treatment allocation, further knowledge about the molecular characteristics of the oligometastatic state is necessary. Here, we performed a genetic characterization of primary non-small cell lung cancer and corresponding brain metastases. We retrospectively identified patients with oligometastatic non-small cell lung cancer and synchronous (<3 months) or metachronous (>3 months) brain metastases who underwent surgical resection of both primary tumor and brain metastases. Mutation profiling of formalin-fixed paraffin-embedded tumor cell blocks was performed by targeted next generation sequencing using the oncomine focus assay panel. Sequencing was successful in 46 paired samples. An oncogenic alteration was present in 31 primary tumors (67.4%) and 40 brain metastases (86.9%). The alteration of the primary tumors was preserved in the corresponding brain metastases in 29 out of 31 cases (93.5%). The most prevalent oncogenic driver in both primary tumors and brain metastases was a KRAS mutation (n = 21). In 16 patients (34.8%), the brain metastasis harbored additional oncogenic alterations. The presence of a private genetic alteration in the brain metastasis was an independent predictor of shorter overall survival. In oligometastatic non-small cell lung cancer, brain metastases retain the main genetic alterations of the primary tumors. Patients may profit from targeted inhibition of mutated KRAS. Additional private genetic alterations in the brain metastases are dismal.

Different genetic profiles contribute to worse overall survival in patients with leptomeningeal metastases of non-small-cell lung cancer.

To assess the genetic characteristics of central nervous system (CNS) metastases from non-small-cell lung cancer (NSCLC), we gathered the genetic profiles of brain metastases (BM) and leptomeningeal metastases (LM). Our objective was to identify genetic factors contributing to poorer overall survival (OS) in NSCLC patients with LM. This study included 25 consecutive patients with BM and 52 patients with LM from Guangdong Sanjiu Brain Hospital. All participants underwent 168-target panel sequencing. Among the 25 patients with BM, TP53 was the most frequently mutated gene (44%), followed by driver genes such as EGFR and BRAF (40% and 20%, respectively). In patients with BM, EGFR_amp and CDK4 were also frequently mutated, with rates of 20% and 16%, respectively. The genetic landscape of patients with LM differed, with the top mutated genes being EGFR, TP53, EGFR_amp, CDKN2A, CCNE1, CDK4, PMS2, and PIK3CA, with mutation rates of 77%, 69%, 31%, 29%, 13%, 13%, 13%, and 12%, respectively. In our study, patients with LM exhibited significantly worse OS compared to those with BM (p = 0.029). The mutation rates of TP53, EGFR_amp, and CDKN2A varied between patients with LM and those with BM, at 69.23% vs. 44%, 30.77% vs. 20%, and 28.85% vs. 12%, respectively. Further exploration revealed that patients with BM with TP53 mutations had a shorter OS than patients without TP53 mutations (p = 0.014). Similarly, patients with LM and TP53 mutations presented with worse OS than those without TP53 mutations (p = 0.0067). LM patients with CDKN2A deletions had worse OS than those without CDKN2A deletions (p = 0.037). Additionally, patients with EGFR_amp had a shorter OS than those without EGFR_amp (p = 0.044). Patients with LM exhibited significantly worse OS than those with BM. Gene signatures, such as TP53, EGFR_amp, and CDKN2A, may account for shorter outcomes in patients with LM.

Impact of polygenic risk score for triglyceride trajectory and diabetic complications in subjects with type 2 diabetes based on large electronic medical record data from Taiwan: a case control study.

The prevalence of diabetic dyslipidemia has gradually increased worldwide and individuals with hypertriglyceridemia often have a high polygenic burden of triglyceride (TG)-increasing variants. However, the contribution of genetic variants to dyslipidemia in patients with type 2 diabetes (T2D) remains limited. Therefore, in this study, we aimed to investigate the genetic characteristics of longitudinal changes in TG levels among patients with T2D and summarize the genetic effects of polygenic risk score (PRS) on TG trajectory and risk of diabetic complications. We conducted a case-control study. A total of 11,312 patients with T2D with longitudinal TG and genetic data were identified from a large hospital database in Taiwan. We then performed a genome-wide association study and calculated the relative PRS. In total, 21 single-nucleotide polymorphisms (SNPs) related to TG trajectory were identified and yielded an area under the receiver operating characteristic curve (ROC) of 0.712 for high TG trajectory risk among Taiwanese patients with T2D. A cumulative genetic effect was observed for high TG trajectory, even when considering the adherence of a lipid-lowering agent in stratified analysis. An increased PRS increases high TG trajectory risk in a logistic regression model (odds ratio = 1.55; 95% confidence interval [CI] = 1.31-1.83 in the validation cohort). The TG-specific PRS was associated with the risk of diabetic microvascular complications, including diabetic retinopathy and nephropathy (with hazard ratios of 1.11 [95% CI = 1.01-1.21, P = 0.027] and 1.05 [95% CI = 1.01-1.1, P = 0.018], respectively). This study may contribute to the identification of patients with T2D who are at risk of abnormal TG levels and diabetic microvascular complications using polygenic information.

Diagnostics and treatment challenges and research progress in early-onset gastric cancer

The incidence of gastric cancer has decreased, while the occurrence of early-onset gastric cancer has increased. There is no consensus on the definition of early-onset gastric cancer currently. The characteristics of tumor staging and differentiation, coupled with the lack of targeted comprehensive treatment, present a significant clinical challenge in managing early-onset gastric cancer. Relevant studies have analyzed the genetic characteristics of early-onset gastric cancer and have preliminarily revealed its relationship with Helicobacter pylori infection and molecular subtypes. These findings have the potential to contribute to the prevention and personalized treatment of early-onset gastric cancer. In the future, larger-scale evidence-based data are needed to establish diagnostic criteria, elucidate the mechanisms, and develop targeted diagnostic and therapeutic strategies of early-onset gastric cancer.

Detection and Genetic Characterization of Bovine Torovirus in Uruguay

Bovine torovirus (BToV) is an enteric pathogen that may cause diarrhea in calves and adult cattle, which could result in economic losses due to weight loss and decreased milk production. This study aimed to report the presence, the genetic characterization and the evolution of BToV in calves in Uruguay. BToV was detected in 7.9% (22/278) of fecal samples, being identified in dairy (9.2%, 22/239) but not beef (0.0%, 0/39) calves. BToV was detected in both diarrheic (14%, 6/43) and non-diarrheic (13.2%, 5/38) dairy calves. In addition, BToV was detected in the intestinal contents of 14.9% (7/47) of naturally deceased dairy calves. A complete genome (28,446 nucleotides) was obtained, which was the second outside Asia and the first in Latin America. In addition, partial S gene sequences were obtained to perform evolutionary analyses. Nucleotide and amino acid substitutions within and between outbreaks/farms were observed, alerting the continuous evolution of the virus. Through Bayesian analysis using BEAST, a recent origin (mid-60s) of BToV, possibly in Asia, was estimated, with two introductions into Uruguay from Asia and Europe in 2004 and 2013, respectively. The estimated evolutionary rate was 1.80 × 10−3 substitutions/site/year. Our findings emphasize the importance of continued surveillance and genetic characterization for the effective management and understanding of BToV’s global epidemiology and evolution.

Changes in the corn yield structure depending on genetic characteristics, background mineral nutrition and sowing time in the Khabarovsk Krai

This study presents the results of a three-factor experiment on corn yield structure depending on the genetic characteristics and hybrids, mineral nutrition background and sowing dates. The experiment was carried out in Khabarovsk Krai in fourfold repetition on corn crops of local selection varieties Birsu, ALitet 2 and Guran 2 and hybrids of foreign selection Moldavsky 215 SV, P 7515, P 8521, P 7460; on three mineral nutrition backgrounds: № 1 (control) – N90P90K90, № 2 – N110P110K90, № 3 – N130P130K90; in 2 sowing dates with 5 days apart. The studies were carried out in 2021–2022 on the experimental field of the Far Eastern Agricultural Research Institute, the soil of the experimental section was meadow-brown, heavy loamy. The highest grain yield up to 125.3 c/ha was noted on the mineral nutrition background № 2 (N110P110K90) and № 3 (N130P130K90). Yield structure indicators depended more on varietal features of plants (46.0–73.4%) rather than on mineral nutrition background (6.2–17.8%) and sowing dates had sufficient influence (0.18–2.59%). However, the weight of 1000 grains was more influenced by additional application of nitrogen and phosphorus (40.67%) rather than varietal features (32.71%). In this study varieties of local breeding Alitet 2 and Guran 2 are recommended for cultivation in Khabarovsk Krai as they give a good grain yield, responsive to the additional application of nitrogen and phosphorus, correspond to the region conditions in terms of precocity, suitable both for harvesting silage and green fodder and for harvesting grain forage.

Genetic characterization and evidence for multiple reassortments of rotavirus A G3P[3] in dogs and cats in Thailand

Rotavirus A (RVA) causes gastroenteritis in humans and animals. The zoonotic potential of RVA has been reported and raises major concerns, especially in animal-human interface settings. The study aimed to characterize and investigate the genetic diversity among RVAs in dogs and cats in Thailand. We collected 572 rectal swab samples from dogs and cats in Bangkok animal hospitals from January 2020 to June 2021. The one-step RT-PCR assay detected RVAs in 1.92% (11/572) of the samples, with 2.75% (8/290) in dogs and 1.06% (3/282) in cats. Two canine RVA and one feline RVA were subjected to whole genome sequencing. Our results showed that all three viruses were identified as RVA genotype G3P[3]. The genetic constellation of RVAs is unique for different species. For canine RVAs is G3-P [3]-I3-R3-C3-M3-A9-N2-T3-E3-H6, while Feline RVA is G3-P [3]-I8-R3-C3-M3-A9-N3-T3-E3-H6. Notably, both canine and feline RVAs contained the AU-1 genetic constellation with multiple reassortments. The results of phylogenetic, genetic, and bootscan analyses showed that canine RVAs may have reassorted from dog, human, and cat RVAs. While feline RVA was closely related to RVAs in humans, bats, and simians. This study provided genetic characteristics and diversity of RVAs in dogs and cats and suggested possible multiple reassortments, suggesting the zoonotic potential of the viruses. Thus, public health awareness should be raised regarding the zoonotic potential of RVAs in dogs and cats. Further studies on RVAs on a larger scale in dogs and cats in Thailand are needed.

A Capillary-Force-Driven, Single-Cell Transfer Method for Studying Rare Cells

The characterization of individual cells within heterogeneous populations (e.g., rare tumor cells in healthy blood cells) has a great impact on biomedical research. To investigate the properties of these specific cells, such as genetic biomarkers and/or phenotypic characteristics, methods are often developed for isolating rare cells among a large number of background cells before studying their genetic makeup and others. Prior to using real-world samples, these methods are often evaluated and validated by spiking cells of interest (e.g., tumor cells) into a sample matrix (e.g., healthy blood) as model samples. However, spiking tumor cells at extremely low concentrations is challenging in a standard laboratory setting. People often circumvent the problem by diluting a solution of high-concentration cells, but the concentration becomes inaccurate after series dilution due to the fact that a cell suspension solution can be inhomogeneous, especially when the cell concentration is very low. We report on an alternative method for low-cost, accurate, and reproducible low-concentration cell spiking without the use of external pumping systems. By inducing a capillary force from sudden pressure drops, a small portion of the cellular membrane was aspirated into the reservoir tip, allowing for non-destructive single-cell transfer. We investigated the surface membrane tensions induced by cellular aspiration and studied a range of tip/tumor cell diameter combinations, ensuring that our method does not affect cell viability. In addition, we performed single-cell capture and transfer control experiments using human acute lymphoblastic leukemia cells (CCRF-CEM) to develop calibrated data for the general production of low-concentration samples. Finally, we performed affinity-based tumor cell isolation using this method to generate accurate concentrations ranging from 1 to 15 cells/mL.

Clinical characteristics and genetic substrate of lone atrial fibrillation: a single center experience

Abstract Background Juvenile-onset lone atrial fibrillation (LAF) may be the initial manifestation of a concealed channelopathy or cardiomyopathy (CMP) or it may be due to an atrial specific genetic susceptibility. Clinical characteristics, genetic background and proper management are still largely unknown. Purpose Aim of the present study is to describe the clinical and genetic characteristics of patients with juvenile-onset LAF. Methods We enrolled patients referred to our center for ablation between 1/2018 and 11/2023 with a first diagnosis of LAF before the age of 60, a structurally normal heart (absence of known CMP, ischemic, valvular, congenital heart disease) and no overt channelopathy. A concealed Brugada syndrome was systematically excluded. Genetic testing was performed using Next Genome Sequencing and a dedicated gene panel. Results 89 patients were included (84% male, LAF onset 43 ± 8 years, BMI 25 ± 7 kg/m2): 32% had a first-degree family history of AF (including 15% below 60 years), 18% of sudden death, 8% of cardiac conduction disorders and 2% of CMP. Cardiovascular risk factors included arterial hypertension in 24%, smoking in 47% and obstructive sleep apnea syndrome in 4%; 20% were competitive athletes. Most patients (89%) presented with paroxysmal AF and 92% were symptomatic (mainly palpitations). At presentation LVEF was 61±5% and LAVI 35±14 ml/m2. Median follow-up time after the first AF episode was 6 years (IQR 4-10). Most patients (81, 91%) underwent at least one transcatheter ablation procedure after failed anti-arrhythmic drug (AAD) therapy (mostly IC). The first procedure (73% radiofrequency, 27% cryoablation) included pulmonary veins isolation (PVI) in all and additional lesions in 5%; the second procedure (n=18, 22% of the ablation group) included PV re-isolation in all (mostly due to multiple vein reconnections) and additional lesions in 17%; the third procedure (n=8, 10% of the ablation group) included PV re-isolation in 25% and additional lesions in 75%. The remaining 8 patients were treated with AAD only (mostly IC). By the last follow-up, 7% of patients in the ablation group and 25% in the AAD group had documented recurrences (even though 50% of those who received ablation were still on AAD). Among the 35 patients subjected to genetic investigation, 10 have available results: 30% tested positive for C4-C5 variants (2 for KCNQ1, 1 for TTN), 50% for C3 variants (RYR2, ABCC9, LMNA, KCNH2 and RMB20) and 20% were negative. Conclusions In the present single center cohort of patients with juvenile-onset LAF, a positive family history was found in almost one third of patients. Despite prompt diagnosis and treatment (including &amp;gt;1 ablation in 20% of patients), recurrences rate is not trivial. The yield of genetic test so far is high, supporting its use in this population.

Expanding the spectrum of clinical and genetic characteristics of distal arthrogryposis type 5 caused by heterozygous variants in the PIEZO2 gene

Expanding the spectrum of clinical and genetic characteristics of distal arthrogryposis type 5 caused by heterozygous variants in the PIEZO2 gene

Molecular Characterization of the Chicken Parvovirus Based on VP1 Gene Circulating in Brazilian Chicken Flocks

Parvovirus infection affects several animal species, especially young animals. In birds, parvovirus infection has been described in Muscovy ducks, turkeys, and chickens, all of which had enteric diseases characterized by diarrhea. Chicken parvovirus (ChPV) has been detected in poultry around the world in animals affected by enteric problems, showing dwarfism, cloacal pasting, and diarrhea. In Brazil, ChPV was detected in chickens affected by diarrhea fifteen years ago. However, the genetic characteristics of ChPV circulating in chicken flocks were not determined. Therefore, the aim of the present investigation was to determine the genetic characteristics of the VP1 gene from ChPV detected in chickens affected by enteric diseases in Brazil. For this purpose, a molecular approach was used. Specific primers were designed to flank the complete VP1 gene of ChPV and amplify it using PCR. The amplified products from samples of chickens with enteric diseases were sequenced, and 22 complete CDs of the VP1 gene were obtained. These samples, compared to the ABU-P1 sequence, showed 17 sequences with high nucleotide (NT) similarity of 92.7–97.4% and amino acid (AA) similarity of 94.8–99.5% associated with Runting and Stunting syndrome (RSS); there were also five samples associated with hens with diarrhea with unusual jejunal dilatation (JD) that had less similarity than the RSS sequences (NT of 86.5% and AA of 93–93.1%). The phylogenetic analysis determined four groups. Group I had sequences from Korea. The second group included sequences from Korea, China, and Brazil (not included in this work). The third group had studied RSS sequences grouped with the ABU-P1 strain and sequences from China and the United States. Finally, the sequences from JD were clustered in a separate group with a bootstrap of 100%, a group that was denoted as group IV, and included sequences from China. RDP4 and SimPlot analysis showed one point of recombination with the sequences of group III ChPV in the JD sequences. Herein, we show that circulating strains of ChPV exhibit genetic differences in the VP1 gene in Brazilian chicken flocks. Nevertheless, more studies are needed to determine the probability of a new genetic group of ChPV based on the analysis of the complete genome.