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Expanded CGG-repeats have been linked to neurodevelopmental and neurodegenerative disorders, including the fragile X syndrome and fragile X-associated tremor/ataxia syndrome (FXTAS). We hypothesized that as of yet uncharacterised CGG-repeat expansions within the genome contribute to human disease. To catalogue the CGG-repeats, 544 human whole genomes were analyzed. In total, 6101 unique CGG-repeats were detected of which more than 93% were highly variable in repeat length. Repeats with a median size of 12 repeat units or more were always polymorphic but shorter repeats were often polymorphic, suggesting a potential intergenerational instability of the CGG region even for repeats units with a median length of four or less. 410 of the CGG repeats were associated with known neurodevelopmental disease genes or with strong candidate genes. Based on their frequency and genomic location, CGG repeats may thus be a currently overlooked cause of human disease.
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http://dx.doi.org/10.1038/s41598-021-82050-5 | DOI Listing |
EMBO Rep
August 2025
Institute of Epigenetics and Stem Cells (IES), Helmholtz Munich, Feodor-Lynen-Strasse 21, Munich, 81377, Germany.
The CGG triplet repeat binding protein 1 (CGGBP1) binds to CGG repeats and has several important cellular functions, but how this DNA sequence-specific binding factor affects transcription and replication processes is an open question. Here, we show that CGGBP1 binds human gene promoters containing short (< 5) CGG-repeat tracts prone to R-loop formation. Loss of CGGBP1 leads to deregulated transcription, transcription-replication-conflicts (TRCs) and accumulation of Serine-5 phosphorylated RNA polymerase II (RNAPII), indicative of promoter-proximal stalling and a defect in transcription elongation.
View Article and Find Full Text PDFInt J Mol Sci
August 2025
Department of Pathology, Faculty of Medicine, Prince of Songkla University, Songkhla 90110, Thailand.
Fragile X syndrome (FXS) is the most common form of X-linked intellectual disability (ID). This study aimed to share 30 years of experience in diagnosing FXS and determine its frequency in Thailand. We retrospectively reviewed 1480 unrelated patients (1390 males and 90 females) with ID, developmental delay, or autism spectrum disorder, or individuals referred for FXS DNA testing at Songklanagarind Hospital, Thailand, over a 30-year period.
View Article and Find Full Text PDFmedRxiv
July 2025
Department of Psychiatry, University of California San Diego, La Jolla, CA, USA.
Long-read whole genome sequencing (LR-WGS) technologies enhance the discovery of structural variants (SVs) and tandem repeats (TRs). Application of LR-WGS has potential to identify novel risk factors that contribute to autism spectrum disorder (ASD). We performed LR-WGS on 243 individuals from 63 ASD families and generated an integrated call set combining long- and short-read data.
View Article and Find Full Text PDFeNeurologicalSci
September 2025
Omagari Kosei Medical Center, Department of Neurology, Japan.
FXTAS (Fragile X-associated tremor/ataxia syndrome) is characterized by typical clinical features, including tremor, cerebellar ataxia, parkinsonism, and the middle cerebellar peduncle (MCP) sign, which appears as T2 hyperintensity in the MCP on MRI. FXTAS is almost never considered in the context of cervical dystonia. However, this case demonstrates that FXTAS can initially present with cervical dystonia.
View Article and Find Full Text PDFMov Disord
August 2025
Department of Neuromuscular Diseases, UCL Queen Square Institute of Neurology, University College London, London, UK.
Background: Progressive myoclonic epilepsy is a heterogeneous neurodegenerative disorder characterized by early-onset myoclonus, epilepsy, generalized tonic-clonic seizures, and progressive neurological deterioration. Recently, a CGG repeat expansion and increased CSNK1E DNA methylation have been shown to be associated with developmental and epileptic encephalopathies.
Objective: To identify structural variants or repeat expansions associated with progressive myoclonic epilepsy in an Azerbaijani family using long-read sequencing.