Fragile X Syndrome (FXS, MIM 309550) is mainly due to the expansion of a CGG trinucleotide repeat sequence, found in the 5' untranslated region of the FMR1 gene. Some studies suggest that stable markers, such as single nucleotide polymorphisms (SNPs) and the study of populations with genetic identity, could provide a distinct advance to investigate the origin of CGG repeat instability. In this study, seven SNPs (WEX28 rs17312728:G>T, WEX70 rs45631657:C>T, WEX1 rs10521868:A>C, ATL1 rs4949:A>G, FMRb rs25707:A>G, WEX17 rs12010481:C>T and WEX10 ss71651741:C>T) have been analyzed in two Basque valleys (Markina and Arratia). We examined the association between these SNPs and the CGG repeat size, the AGG interruption pattern and two microsatellite markers (FRAXAC1 and DXS548). The results suggest that in both valleys WEX28-T, WEX70-C, WEX1-C, ATL1-G, and WEX10-C are preferably associated with cis-acting sequences directly influencing instability. But comparison of the two valleys reveals also important differences with respect to: (1) frequency and structure of "susceptible" alleles and (2) association between "susceptible" alleles and STR and SNP haplotypes. These results may indicate that, in Arratia, SNP status does not identify a pool of susceptible alleles, as it does in Markina. In Arratia valley, the SNP haplotype association reveals also a potential new "protective" factor.
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http://dx.doi.org/10.1111/j.1469-1809.2011.00696.x | DOI Listing |
Fragile X Syndrome (FXS) is characterized by intellectual impairment caused by CGG repeat expansion in the FMR1 gene. When repeats exceed 200, they induce DNA methylation of the promoter and the repeat region, resulting in transcriptional silencing of the FMR1 gene and the subsequent loss of FMRP protein. In the past decade or so, research has focused on the role of FMRP as an RNA-binding protein involved in translation inhibition in the brain in FXS model mice, particularly by slowing or stalling ribosome translocation on mRNA.
View Article and Find Full Text PDFInt J Mol Sci
November 2024
Department of Biomedicine, University of Basel, Mattenstrasse 28, 4058 Basel, Switzerland.
Fragile X Syndrome (FX) is the most common form of inherited cognitive impairment and falls under the broader category of Autism Spectrum Disorders (ASD). FX is caused by a CGG trinucleotide repeat expansion in the non-coding region of the X-linked () gene, leading to its hypermethylation and epigenetic silencing. Animal models of FX rely on the deletion of the gene, which fails to replicate the epigenetic silencing mechanism of the gene observed in human patients.
View Article and Find Full Text PDFFront Microbiol
November 2024
Department of Biology, University of Maragheh, Maragheh, Iran.
Clustered regularly interspaced short palindromic repeats (CRISPR) and CRISPR-associated (CAS) genes make up bacteria's adaptive immune system against bacteriophages. In this study, 675 sequences of isolates deposited in GenBank were analyzed in terms of diversity, occurrence, and evolution of the CRISPR-Cas system. This study investigated the presence, structural variations, phylogenetic relationships, and diversity of CRISPR-Cas systems in 675 strains.
View Article and Find Full Text PDFFront Cardiovasc Med
November 2024
Department of Neuroscience, Rehabilitation, Ophthalmology, Genetics, Maternal and Child Health (DINOGMI), University of Genoa, Genoa, Italy.
Spontaneous coronary artery dissection (SCAD) is a relevant non-atherosclerotic cause of acute coronary syndrome with a complex genetic architecture. Recent discoveries have highlighted the potential role of miRNAs and protein-coding genes involved in the processing of small RNAs in the pathogenesis of SCAD. Furthermore, there may be a connection between SCAD and the increased cardiovascular risk observed in fragile X premutation carriers as well as a correlation with pathogenetic variants in genes encoding for collagen and extracellular matrix, which are related to connective tissue disorders (CTDs).
View Article and Find Full Text PDFMol Genet Genomic Med
November 2024
Department of Biochemistry and Molecular Medicine, University of California, Davis, California, USA.
Background: Premutation alleles of the FMR1 X-linked gene containing CGG repeat expansions ranging from 55 to 200 are associated with diverse late-onset neurological involvements, including most severe disorder termed Fragile X-associated Tremor/Ataxia Syndrome (FXTAS). It is intriguing that at least one-third of male, and a much lower than predicted from the X-linkage proportion of female carriers are free of this syndrome. This suggests the existence of secondary genetic factors modifying the risk of neurological involvements in these carriers.
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