H19 and IGF2 genes are imprinted genes and expressed differently depending on whether they are carried by a chromosome of maternal or paternal origin; H19 is expressed only from the maternal allele and IGF2 only from the paternally inherited allele. The upstream promoter region of H19 has the imprinting-control region (ICR) or CTCF binding sites, where the methylation status of this region is critical to the regulation of imprinting of the H19/IGF2 locus located in chromosome 11p15. There are various reports on imprinting disorders in this region. In colorectal cancer aberrant biallelic methylation of CTCF binding site has been reported, and aberrant hypomethylation of this region in bladder cancer. Thus, certain human neoplasms have either hyper- or hypo-methylation in the ICR. Hence it is still difficult to analyze allele-specific methylation disorder of the region, or differentially methylated regions (DMR), locate upstream of H19. Here we report a new method, which could distinguish paternal epigenetic or maternal epigenetic pattern by a single PCR assay, to combine methylation-specific PCR and PCR with confronting two-pair primers (MSP-CTPP). Using this method, we investigated the region close to H19 ICR in 161 colorectal cancer and 65 gastric cancer cases.
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Int J Mol Sci
December 2024
Center for Individualized Medicine, Mayo Clinic, Rochester, MN 55905, USA.
DNA methylation is an essential epigenetic modification that plays a crucial role in regulating gene expression and maintaining genomic stability. With the advancement in sequencing technology, methylation studies have provided valuable insights into the diagnosis of rare diseases through the various identification of episignatures, epivariation, epioutliers, and allele-specific methylation. However, current methylation studies are not without limitations.
View Article and Find Full Text PDFInt J Mol Sci
December 2024
Laboratory of Medical Biology-Genetics, Faculty of Medicine, School of Health Sciences, Aristotle University, 54124 Thessaloniki, Greece.
This study aimed to investigate whether genes with different modes of inheritance differ in the presence of promoter-enriched CGI loci. For each autosomal chromosome, the author searched for variations in the total number of diseases' phenotypes with autosomal dominant (AD) and recessive (AR) inheritance for a list of promoter-poor CGI (CGI-) and promoter-enriched CGI (CGI+) genes using the OMIM database. Then, the CGI- and CGI+ genes displaying random allelic or bi-allelic expression were examined.
View Article and Find Full Text PDFBiol Sex Differ
January 2025
Department of Laboratory Medicine and Pathology, School of Medicine, University of Washington, Seattle, WA, 98195, USA.
Background: X chromosome inactivation (XCI) is a female-specific process in which one X chromosome is silenced to balance X-linked gene expression between the sexes. XCI is initiated in early development by upregulation of the lncRNA Xist on the future inactive X (Xi). A subset of X-linked genes escape silencing and thus have higher expression in females, suggesting female-specific functions.
View Article and Find Full Text PDFClin Epigenetics
December 2024
Hereditary Cancer Group, ONCOBELL Program, Institut d'Investigació Biomèdica de Bellvitge (IDIBELL), L'Hospitalet de Llobregat, Spain.
Background: Lynch syndrome (LS), characterised by an increased risk for cancer, is mainly caused by germline pathogenic variants affecting a mismatch repair gene (MLH1, MSH2, MSH6, PMS2). Occasionally, LS may be caused by constitutional MLH1 epimutation (CME) characterised by soma-wide methylation of one allele of the MLH1 promoter. Most of these are "primary" epimutations, arising de novo without any apparent underlying cis-genetic cause, and are reversible between generations.
View Article and Find Full Text PDFJCI Insight
December 2024
Department of Ophthalmology and Roger and Karalis Johnson Retina Center, University of Washington, Seattle, United States of America.
Background: Current clinical sequencing methods cannot effectively detect DNA methylation and allele-specific variation to provide parent-of-origin information from the proband alone. Parent-of-origin effects can lead to differential disease and the inability to assign this in de novo cases limits prognostication in the majority of affected individuals with retinoblastoma, a hereditary cancer with suspected parent-of-origin effects.
Methods: To directly assign parent-of-origin in retinoblastoma patients, genomic DNA was extracted from blood samples for sequencing using a programmable, targeted single-molecule long-read DNA genomic and epigenomic approach.
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