3449 results for "*geneti*"

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• ecDNA copy number heterogeneity

  Neuroblastoma exhibits significant inter- and intra-tumour genetic heterogeneity and varying clinical outcomes. Here, we used DNA and RNA sequencing from the same single cells in cell lines and neuroblastoma patients to investigate these effects. We reveal extensive intercellular ecDNA copy number heterogeneity. We also provide direct evidence of how this heterogeneity influences the expression of cargo genes, including MYCN and its downstream targets, and the overall transcriptional state of neuroblastoma cells.

  Study EGAS50000000509

• Repeat expansions with small TTTCA insertions in MARCHF6 cause Familial Adult Myoclonus without Epilepsy

  Familial Adult Myoclonic Epilepsy (FAME) is a rare autosomal dominant disorder characterized by cortical tremulous myoclonus and generalized tonic clonic (GTCS) or myoclonic seizures. Intrafamilial variability regarding the prevalence of seizure has been reported. Despite apparent genetic heterogeneity, FAME is caused by the same TTTTA/TTTCA pentanucleotide repeat expansion in introns of seven different genes with no common function. Expansions containing only TTTTA repeats are benign, and only expansions including a TTTCA expansion insertion, which can be located 3' to the TTTTA expansion or in the middle of the TTTTA repeats, are pathogenic. We aimed to identify the underlying genetic cause of dominant cortical myoclonus without GTCS in two unrelated families. We used a combination of repeat-primed PCR, long-range PCR and nanopore sequencing to detect and characterize expansions at known FAME loci. We report a novel configuration of the FAME3 repeat expansion in MARCHF6 segregating with cortical myoclonus without epilepsy GTCS in both families. This expansion predominantly comprises elongated TTTTA repeats, ranging from 388 to 454 repeats, with the presence of only 5-11 TTTCA repeats at its 3' terminus (i.e., 5’-(TTTTA)~388-454(TTTCA)5-11-3’). This configuration exhibits greater stability upon meiotic transmission but somatic variability in TTTCA repeat number was detected at low level in blood. We observed an inverse correlation between the number of TTTCA repeats and the age at myoclonus onset. This study shows that as little as five TTTCA juxtaposed with expanded TTTTA expansions is sufficient to cause cortical myoclonus without GTCS. This finding has implications regarding possible pathophysiological mechanisms leading to FAME.

  Study EGAS50000000570

• CpG methylation changes associated with hyperglycemia in type 1 diabetes occur at angiogenic glomerular and retinal gene loci.

  Retinal and glomerular microangiopathy, and cardiovascular disease, contribute to the morbidity and mortality observed in adults with type 1 diabetes (T1D). While the level and duration of hyperglycemia are primary factors influencing these complications, the underlying molecular mechanisms behind glucose-induced organ damage remain poorly understood. In this study, blood samples from young T1D patients at diagnosis and three years later in average were analyzed for DNA methylation using whole-genome bisulfite sequencing. Significant DNA methylation changes in critical angiogenic gene loci were associated with HbA1c, a direct hallmark of chronic hyperglycemia. This finding may offer novel epigenetic insights for a better understanding of T1D complications.

  Study EGAS50000000370

• Whole Exome Sequencing Data of prDLBCL

  We used sequenced 34 prDLBCL samples using whole exome sequencing (WES) data to evaluate possible mutational signatures and driver mutations associated with the patient’s clinical and cytogenetic characteristics.

  Dataset EGAD50000000591

• Contribution of specific cell types to the development of Barrett’s esophagus and carcinoma via germline genetic risk

  This study was designed to elucidate how individual cell types in Barrett’s esophagus (BE) and esophageal adenocarcinoma (EAC) contribute to disease development via germline genetic risk. We performed single cell RNA-sequencing (scRNA-seq) of BE, EAC and paired normal esophagus and gastric fundus tissue samples. After analyzing individual cell types, we integrated the scRNA-seq data and data of a genome-wide association study (GWAS) on BE/EAC to determine cell type-specific genetic risk. Raw data from the RNA-sequencing is provided here.

  Study EGAS50000000530

• Contribution of specific cell types to the development of Barrett’s esophagus and carcinoma via germline genetic risk

  We sought to elucidate how individual cell types in Barrett’s esophagus (BE) and esophageal adenocarcinoma (EAC) contribute to disease development via germline genetic risk.

  Dac EGAC50000000235

• Tumor Evolution Analysis Uncovered Immune-Escape Related Mutations in Relapsed Diffuse Large B-Cell Lymphoma

  More than 60% of patients with primary diffuse large B-cell lymphoma (DLBCL) achieve durable remissions upon the chemoimmunotherapy with R-CHOP. However, the outcome of the relapse patients is extremely poor. To characterize the molecular features that underlie treatment resistance, we performed whole-exome sequencing (n=44) and deep targeted sequencing (n=27) of 44 diagnosis-relapse DLBCL pairs. We found that the overall landscape of genetic alterations was concordant between diagnosis and relapse DLBCL. By a deep comparison of the longitudinal sequencings, we identified relapse-enriched mutations that involved in evasion of immune surveillance (CD58, TNFRSF14, PKD1, FAS), resistance to DNA damaging agents (ATM, TP53), and critical tumor suppressor gene (ZFHX3). Knockdown of ATM and ZFHX3 resulted in increased drug resistance in both germinal center B cell like (GCB) and activated B cell like (ABC) DLBCL cell lines in vitro, while the knockdown of TNFRSF14 and FAS conferred resistance specifically in GCB cell lines. Furthermore, we summarized two evolutionary patterns of DLBCL relapse as the “durable retention” model with stable clone structure, and the “selective sweep” model which exhibited significant clonal switch. Of note, genetic alterations leading to attenuated immune responses usually presented as trunk mutations in the “durable retention” model (7/12) while were newly acquired or expanded upon relapse in the “selective sweep” model (9/16). Overall, our study demonstrated that relapse DLBCL derives from distinct clonal evolutionary patterns, and highlighted immune escape as an important contributor of tumor relapse.

  Study EGAS50000000032

• Data Access Committee Clinical Genetics at Karolinska Institutet (DAC-CG-KI)

  Dac EGAC00001002960

• Genomic determinants of response and resistance to inotuzumab in B-ALL

  Inotuzumab Ozogamicin (InO) is an antibody-drug conjugate which delivers calicheamicin to CD22-expressing cells. In a retrospective cohort of InO treated B-cell acute lymphoblastic leukemia (B-ALL) patients, we sought to understand the genomic determinants of response to InO. Acquired CD22 mutations were observed in 11% (3/27) of post-InO relapsed samples. CD22 mutation types were diverse (frameshift, nonsense, missense and stoploss) and we identified multiple mechanisms of mutation induced CD22 escape, including protein truncation, protein destabilization, and epitope alteration. Accelerated acquisition of mutations by error-prone DNA damage repair could drive CD22 mutation and escape. Acquired loss-of-function mutations in TP53, ATM and CDKN2A were observed, suggesting compromise of the G1/S DNA damage checkpoint as a mechanism of evading InO-induced apoptosis. In conclusion, genetic alterations modulating CD22 expression and DNA damage response influence InO efficacy. The diverse mechanisms of CD22 escape advocates for a refined approach for monitoring CD22-targeted therapy.

  Study EGAS50000000067

• A GWAS study with the AlpeDPD study cohort

  A genome-wide association study (GWAS) with patients treated with fluoropyrimidines was performed to identify genetic variants linked to the severe fluoropyrimidine-related toxicity.

  Study EGAS00001007855