Rett syndrome (RTT) whose major cause is the mutations in the X-linked MECP2 gene is a genetic disease that affects females. We screened two RTT patients using cytogenetic studies and in silico analysis as well as molecular analysis by the direct sequencing of MECP2. The cytogenetic results showed that although patient A was karyotypically normal, patient B showed chromosomal abnormalities, including chromosomal breakage in both chromosomes 2 and 5. In addition, chromosome 9 was detected on heteromorphic pattern (9ph+). A significant increase in sister-chromatid exchange (SCE) frequency was also observed in this patient. Although both patients were karyotypically different, they share the same MeCP2 mutation (p.P152R) which was predicted to be deleterious. To our knowledge, we describe the first association between MECP2 mutation, chromosomal abnormalities and high SCE frequency, which further validates the importance of the thorough chromosomal and molecular analyses that should be performed on the suspected RTT cases.
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http://dx.doi.org/10.1007/s13760-016-0667-5 | DOI Listing |
Genome Med
December 2024
Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, 77030, USA.
Background: MECP2 Duplication Syndrome, also known as X-linked intellectual developmental disorder Lubs type (MRXSL; MIM: 300260), is a neurodevelopmental disorder caused by copy number gains spanning MECP2. Despite varying genomic rearrangement structures, including duplications and triplications, and a wide range of duplication sizes, no clear correlation exists between DNA rearrangement and clinical features. We had previously demonstrated that up to 38% of MRXSL families are characterized by complex genomic rearrangements (CGRs) of intermediate complexity (2 ≤ copy number variant breakpoints < 5), yet the impact of these genomic structures on regulation of gene expression and phenotypic manifestations have not been investigated.
View Article and Find Full Text PDFNeuron
December 2024
Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA; Jan and Dan Duncan Neurological Research Institute at Texas Children's Hospital, Houston, TX 77030, USA; Department of Pediatrics, Baylor College of Medicine, Houston, TX 77030, USA; Howard Hughes Medical Institute, Baylor College of Medicine, Houston, TX 77030, USA. Electronic address:
Mutations in the X-linked methyl-CpG-binding protein 2 (MECP2) gene cause Rett syndrome, a severe childhood neurological disorder. MeCP2 is a well-established transcriptional repressor, yet upon its loss, hundreds of genes are dysregulated in both directions. To understand what drives such dysregulation, we deleted Mecp2 in adult mice, circumventing developmental contributions and secondary pathogenesis.
View Article and Find Full Text PDFDNA Repair (Amst)
November 2024
Division of Molecular Oncological Pharmacy, Faculty of Pharmacy, Keio University, 1-5-30, Shibakoen, Minato-ku, Tokyo 105-8512, Japan. Electronic address:
DNA double-strand breaks (DSBs) trigger the recruitment of repair protein and promote signal transduction through posttranslational modifications such as phosphorylation. After DSB induction, ataxia telangiectasia mutated (ATM) phosphorylates H2AX on chromatin surrounds the mega-base pairs proximal to the DSBs. Advanced super-resolution microscopic technology has demonstrated the formation of γH2AX nano foci as a unit of nano domain comprised of multiple nucleosomes.
View Article and Find Full Text PDFKey Clinical Message: This study reports a Chinese male patient with a novel MeCP2 p.Lys254*variant. Upon birth, the patient presented with typical symptoms, such as abnormal electroencephalogram, immature sleep rhythm, hypotonia, feeding difficulties, pulmonary fluid accumulation, horizontal fissures in the lungs, hypoventilation, and heart defects.
View Article and Find Full Text PDFNat Neurosci
November 2024
Department of Neuroscience, Peter O'Donnell Jr. Brain Institute, UT Southwestern Medical Center, Dallas, TX, USA.
Mutations in methyl-CpG-binding protein 2 (MeCP2) cause Rett syndrome. MeCP2 is thought to regulate gene transcription by binding to methylated DNA broadly across the genome. Here, using cleavage under target and release under nuclease (CUT&RUN) assays in the adult mouse cortex, we show that MeCP2 strongly binds to specific gene enhancers that we call MeCP2-binding hotspots (MBHs).
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