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Zhang Y, Liu X, Li Z, Li H, Miao Z, Wan B, Xu X. Advances on the Mechanisms and Therapeutic Strategies in Non-coding CGG Repeat Expansion Diseases. Mol Neurobiol 2024:10.1007/s12035-024-04239-9. [PMID: 38780719 DOI: 10.1007/s12035-024-04239-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2023] [Accepted: 05/02/2024] [Indexed: 05/25/2024]
Abstract
Non-coding CGG repeat expansions within the 5' untranslated region are implicated in a range of neurological disorders, including fragile X-associated tremor/ataxia syndrome, oculopharyngeal myopathy with leukodystrophy, and oculopharyngodistal myopathy. This review outlined the general characteristics of diseases associated with non-coding CGG repeat expansions, detailing their clinical manifestations and neuroimaging patterns, which often overlap and indicate shared pathophysiological traits. We summarized the underlying molecular mechanisms of these disorders, providing new insights into the roles that DNA, RNA, and toxic proteins play. Understanding these mechanisms is crucial for the development of targeted therapeutic strategies. These strategies include a range of approaches, such as antisense oligonucleotides, RNA interference, genomic DNA editing, small molecule interventions, and other treatments aimed at correcting the dysregulated processes inherent in these disorders. A deeper understanding of the shared mechanisms among non-coding CGG repeat expansion disorders may hold the potential to catalyze the development of innovative therapies, ultimately offering relief to individuals grappling with these debilitating neurological conditions.
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Affiliation(s)
- Yutong Zhang
- Departments of Neurology, The First Affiliated Hospital of Soochow University, Suzhou City, China
| | - Xuan Liu
- Departments of Neurology, The First Affiliated Hospital of Soochow University, Suzhou City, China
| | - Zeheng Li
- Departments of Neurology, The First Affiliated Hospital of Soochow University, Suzhou City, China
| | - Hao Li
- Departments of Neurology, The First Affiliated Hospital of Soochow University, Suzhou City, China
- Department of Neurology, The Fourth Affiliated Hospital of Soochow University, Suzhou, 215124, China
| | - Zhigang Miao
- The Institute of Neuroscience, Soochow University, Suzhou City, China
| | - Bo Wan
- The Institute of Neuroscience, Soochow University, Suzhou City, China
| | - Xingshun Xu
- Departments of Neurology, The First Affiliated Hospital of Soochow University, Suzhou City, China.
- The Institute of Neuroscience, Soochow University, Suzhou City, China.
- Department of Neurology, The First Affiliated Hospital of Soochow University, Suzhou, 215000, China.
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Xu Y, Jiao Y, Liu C, Miao R, Liu C, Wang Y, Ma C, Liu J. R-loop and diseases: the cell cycle matters. Mol Cancer 2024; 23:84. [PMID: 38678239 PMCID: PMC11055327 DOI: 10.1186/s12943-024-02000-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2024] [Accepted: 04/13/2024] [Indexed: 04/29/2024] Open
Abstract
The cell cycle is a crucial biological process that is involved in cell growth, development, and reproduction. It can be divided into G1, S, G2, and M phases, and each period is closely regulated to ensure the production of two similar daughter cells with the same genetic material. However, many obstacles influence the cell cycle, including the R-loop that is formed throughout this process. R-loop is a triple-stranded structure, composed of an RNA: DNA hybrid and a single DNA strand, which is ubiquitous in organisms from bacteria to mammals. The existence of the R-loop has important significance for the regulation of various physiological processes. However, aberrant accumulation of R-loop due to its limited resolving ability will be detrimental for cells. For example, DNA damage and genomic instability, caused by the R-loop, can activate checkpoints in the cell cycle, which in turn induce cell cycle arrest and cell death. At present, a growing number of factors have been proven to prevent or eliminate the accumulation of R-loop thereby avoiding DNA damage and mutations. Therefore, we need to gain detailed insight into the R-loop resolution factors at different stages of the cell cycle. In this review, we review the current knowledge of factors that play a role in resolving the R-loop at different stages of the cell cycle, as well as how mutations of these factors lead to the onset and progression of diseases.
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Affiliation(s)
- Yuqin Xu
- School of Basic Medicine Sciences, Shandong Second Medical University, Weifang, 261053, China
| | - Yue Jiao
- School of Basic Medicine Sciences, Shandong Second Medical University, Weifang, 261053, China
| | - Chengbin Liu
- School of Basic Medicine Sciences, Shandong Second Medical University, Weifang, 261053, China
| | - Rui Miao
- School of Basic Medicine Sciences, Shandong Second Medical University, Weifang, 261053, China
| | - Chunyan Liu
- School of Basic Medicine Sciences, Shandong Second Medical University, Weifang, 261053, China
| | - Yilong Wang
- School of Basic Medicine Sciences, Shandong Second Medical University, Weifang, 261053, China
| | - Chunming Ma
- School of Basic Medicine Sciences, Shandong Second Medical University, Weifang, 261053, China
| | - Jiao Liu
- School of Basic Medicine Sciences, Shandong Second Medical University, Weifang, 261053, China.
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Zeng T, Chen Y, Huang H, Li S, Huang J, Xie H, Lin S, Chen S, Chen G, Yang D. Neuronal Intranuclear Inclusion Disease with NOTCH2NLC GGC Repeat Expansion: A Systematic Review and Challenges of Phenotypic Characterization. Aging Dis 2024:AD.2024.0131-1. [PMID: 38377026 DOI: 10.14336/ad.2024.0131-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2023] [Accepted: 01/31/2024] [Indexed: 02/22/2024] Open
Abstract
Neuronal intranuclear inclusion disease (NIID) is a highly clinically heterogeneous neurodegenerative disorder primarily attributed to abnormal GGC repeat expansions in the NOTCH2NLC gene. This study aims to comprehensively explore its phenotypic characteristics and genotype-phenotype correlation. A literature search was conducted in PubMed, Embase, and the Cochrane Library from September 1, 2019, to December 31, 2022, encompassing reported NIID cases confirmed by pathogenic NOTCH2NLC mutations. Linear regressions and trend analyses were performed. Analyzing 635 cases from 85 included studies revealed that familial cases exhibited significantly larger GGC repeat expansions than sporadic cases (p < 0.001), and this frequency significantly increased with expanding GGC repeats (p trend < 0.001). Age at onset (AAO) showed a negative correlation with GGC repeat expansions (p < 0.001). The predominant initial symptoms included tremor (31.70%), cognitive impairment (14.12%), and muscle weakness (10.66%). The decreased or absent tendon reflex (DTR/ATR) emerged as a notable clinical indicator of NIID due to its high prevalence. U-fiber was observed in 79.11% of patients, particularly prominent in paroxysmal disease-dominant (87.50%) and dementia-dominant cases (81.08%). Peripheral neuropathy-dominant cases exhibited larger GGC repeat expansions (median = 123.00) and an earlier AAO (median = 33.00) than other phenotypes. Moreover, a significant genetic anticipation of 3.5 years was observed (p = 0.039). This study provides a comprehensive and up-to-date compilation of genotypic and phenotypic information on NIID since the identification of the causative gene NOTCH2NLC. We contribute a novel diagnostic framework for NIID to support clinical practice.
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Affiliation(s)
- Tian Zeng
- The First School of Medicine, School of Information and Engineering, Wenzhou Medical University, Wenzhou, China
| | - Yiqun Chen
- The First School of Medicine, School of Information and Engineering, Wenzhou Medical University, Wenzhou, China
| | - Honghao Huang
- Department of Cardiology, Renji Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Shengqi Li
- The First School of Medicine, School of Information and Engineering, Wenzhou Medical University, Wenzhou, China
| | - Jiaqi Huang
- The First School of Medicine, School of Information and Engineering, Wenzhou Medical University, Wenzhou, China
| | - Haobo Xie
- The First School of Medicine, School of Information and Engineering, Wenzhou Medical University, Wenzhou, China
| | - Shenyi Lin
- The First School of Medicine, School of Information and Engineering, Wenzhou Medical University, Wenzhou, China
| | - Siyao Chen
- The First School of Medicine, School of Information and Engineering, Wenzhou Medical University, Wenzhou, China
| | - Guangyong Chen
- Department of Neurology, The Third Affiliated Hospital of Wenzhou Medical University, Wenzhou, China
| | - Dehao Yang
- Department of Neurology, The Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China
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Tassone F, Protic D, Allen EG, Archibald AD, Baud A, Brown TW, Budimirovic DB, Cohen J, Dufour B, Eiges R, Elvassore N, Gabis LV, Grudzien SJ, Hall DA, Hessl D, Hogan A, Hunter JE, Jin P, Jiraanont P, Klusek J, Kooy RF, Kraan CM, Laterza C, Lee A, Lipworth K, Losh M, Loesch D, Lozano R, Mailick MR, Manolopoulos A, Martinez-Cerdeno V, McLennan Y, Miller RM, Montanaro FAM, Mosconi MW, Potter SN, Raspa M, Rivera SM, Shelly K, Todd PK, Tutak K, Wang JY, Wheeler A, Winarni TI, Zafarullah M, Hagerman RJ. Insight and Recommendations for Fragile X-Premutation-Associated Conditions from the Fifth International Conference on FMR1 Premutation. Cells 2023; 12:2330. [PMID: 37759552 PMCID: PMC10529056 DOI: 10.3390/cells12182330] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2023] [Revised: 09/09/2023] [Accepted: 09/12/2023] [Indexed: 09/29/2023] Open
Abstract
The premutation of the fragile X messenger ribonucleoprotein 1 (FMR1) gene is characterized by an expansion of the CGG trinucleotide repeats (55 to 200 CGGs) in the 5' untranslated region and increased levels of FMR1 mRNA. Molecular mechanisms leading to fragile X-premutation-associated conditions (FXPAC) include cotranscriptional R-loop formations, FMR1 mRNA toxicity through both RNA gelation into nuclear foci and sequestration of various CGG-repeat-binding proteins, and the repeat-associated non-AUG (RAN)-initiated translation of potentially toxic proteins. Such molecular mechanisms contribute to subsequent consequences, including mitochondrial dysfunction and neuronal death. Clinically, premutation carriers may exhibit a wide range of symptoms and phenotypes. Any of the problems associated with the premutation can appropriately be called FXPAC. Fragile X-associated tremor/ataxia syndrome (FXTAS), fragile X-associated primary ovarian insufficiency (FXPOI), and fragile X-associated neuropsychiatric disorders (FXAND) can fall under FXPAC. Understanding the molecular and clinical aspects of the premutation of the FMR1 gene is crucial for the accurate diagnosis, genetic counseling, and appropriate management of affected individuals and families. This paper summarizes all the known problems associated with the premutation and documents the presentations and discussions that occurred at the International Premutation Conference, which took place in New Zealand in 2023.
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Affiliation(s)
- Flora Tassone
- Department of Biochemistry and Molecular Medicine, School of Medicine, University of California Davis, Sacramento, CA 95817, USA;
- MIND Institute, University of California Davis, Davis, CA 95817, USA; (B.D.); (D.H.); (V.M.-C.)
| | - Dragana Protic
- Department of Pharmacology, Clinical Pharmacology and Toxicology, Faculty of Medicine, University of Belgrade, 11129 Belgrade, Serbia;
- Fragile X Clinic, Special Hospital for Cerebral Palsy and Developmental Neurology, 11040 Belgrade, Serbia
| | - Emily Graves Allen
- Department of Human Genetics, Emory University School of Medicine, Atlanta, GA 30322, USA; (E.G.A.); (P.J.); (K.S.)
| | - Alison D. Archibald
- Victorian Clinical Genetics Services, Royal Children’s Hospital, Melbourne, VIC 3052, Australia;
- Department of Paediatrics, Faculty of Medicine, Dentistry and Health Sciences, The University of Melbourne, Melbourne, VIC 3052, Australia;
- Genomics in Society Group, Murdoch Children’s Research Institute, Royal Children’s Hospital, Melbourne, VIC 3052, Australia
| | - Anna Baud
- Department of Gene Expression, Institute of Molecular Biology and Biotechnology, Adam Mickiewicz University, Uniwersytetu Poznańskiego 6, 61-614 Poznan, Poland; (A.B.); (K.T.)
| | - Ted W. Brown
- Central Clinical School, University of Sydney, Sydney, NSW 2006, Australia;
- Fragile X Association of Australia, Brookvale, NSW 2100, Australia;
- NYS Institute for Basic Research in Developmental Disabilities, New York, NY 10314, USA
| | - Dejan B. Budimirovic
- Department of Psychiatry, Fragile X Clinic, Kennedy Krieger Institute, Baltimore, MD 21205, USA;
- Department of Psychiatry & Behavioral Sciences-Child Psychiatry, School of Medicine, Johns Hopkins University, Baltimore, MD 21205, USA
| | - Jonathan Cohen
- Fragile X Alliance Clinic, Melbourne, VIC 3161, Australia;
| | - Brett Dufour
- MIND Institute, University of California Davis, Davis, CA 95817, USA; (B.D.); (D.H.); (V.M.-C.)
- Department of Pathology and Laboratory Medicine, Institute for Pediatric Regenerative Medicine, Shriners Hospitals for Children of Northern California, School of Medicine, University of California Davis, Sacramento, CA 95817, USA;
| | - Rachel Eiges
- Stem Cell Research Laboratory, Medical Genetics Institute, Shaare Zedek Medical Center Affiliated with the Hebrew University School of Medicine, Jerusalem 91031, Israel;
| | - Nicola Elvassore
- Veneto Institute of Molecular Medicine (VIMM), 35129 Padova, Italy; (N.E.); (C.L.)
- Department of Industrial Engineering, University of Padova, 35131 Padova, Italy
| | - Lidia V. Gabis
- Keshet Autism Center Maccabi Wolfson, Holon 5822012, Israel;
- Faculty of Medicine, Tel-Aviv University, Tel Aviv 6997801, Israel
| | - Samantha J. Grudzien
- Department of Neurology, University of Michigan, 4148 BSRB, 109 Zina Pitcher Place, Ann Arbor, MI 48109, USA; (S.J.G.); (P.K.T.)
- Neuroscience Graduate Program, University of Michigan, Ann Arbor, MI 48109, USA
- Department of Computational Medicine and Bioinformatics, University of Michigan, Ann Arbor, MI 48109, USA
| | - Deborah A. Hall
- Department of Neurological Sciences, Rush University, Chicago, IL 60612, USA;
| | - David Hessl
- MIND Institute, University of California Davis, Davis, CA 95817, USA; (B.D.); (D.H.); (V.M.-C.)
- Department of Psychiatry and Behavioral Sciences, School of Medicine, University of California Davis, Sacramento, CA 95817, USA
| | - Abigail Hogan
- Department of Communication Sciences and Disorders, Arnold School of Public Health, University of South Carolina, Columbia, SC 29208, USA; (A.H.); (J.K.)
| | - Jessica Ezzell Hunter
- RTI International, Research Triangle Park, NC 27709, USA; (J.E.H.); (S.N.P.); (M.R.); (A.W.)
| | - Peng Jin
- Department of Human Genetics, Emory University School of Medicine, Atlanta, GA 30322, USA; (E.G.A.); (P.J.); (K.S.)
| | - Poonnada Jiraanont
- Faculty of Medicine, King Mongkut’s Institute of Technology Ladkrabang, Bangkok 10520, Thailand;
| | - Jessica Klusek
- Department of Communication Sciences and Disorders, Arnold School of Public Health, University of South Carolina, Columbia, SC 29208, USA; (A.H.); (J.K.)
| | - R. Frank Kooy
- Department of Medical Genetics, University of Antwerp, 2000 Antwerp, Belgium;
| | - Claudine M. Kraan
- Department of Paediatrics, Faculty of Medicine, Dentistry and Health Sciences, The University of Melbourne, Melbourne, VIC 3052, Australia;
- Diagnosis and Development, Murdoch Children’s Research Institute, Melbourne, VIC 3052, Australia
| | - Cecilia Laterza
- Veneto Institute of Molecular Medicine (VIMM), 35129 Padova, Italy; (N.E.); (C.L.)
- Department of Industrial Engineering, University of Padova, 35131 Padova, Italy
| | - Andrea Lee
- Fragile X New Zealand, Nelson 7040, New Zealand;
| | - Karen Lipworth
- Fragile X Association of Australia, Brookvale, NSW 2100, Australia;
| | - Molly Losh
- Roxelyn and Richard Pepper Department of Communication Sciences and Disorders, Northwestern University, Evanston, IL 60201, USA;
| | - Danuta Loesch
- School of Psychology and Public Health, La Trobe University, Melbourne, VIC 3086, Australia;
| | - Reymundo Lozano
- Departments of Genetics and Genomic Sciences and Pediatrics, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA;
| | - Marsha R. Mailick
- Waisman Center, University of Wisconsin-Madison, Madison, WI 53705, USA;
| | - Apostolos Manolopoulos
- Intramural Research Program, Laboratory of Clinical Investigation, National Institute on Aging, Baltimore, MD 21224, USA;
| | - Veronica Martinez-Cerdeno
- MIND Institute, University of California Davis, Davis, CA 95817, USA; (B.D.); (D.H.); (V.M.-C.)
- Department of Pathology and Laboratory Medicine, Institute for Pediatric Regenerative Medicine, Shriners Hospitals for Children of Northern California, School of Medicine, University of California Davis, Sacramento, CA 95817, USA;
| | - Yingratana McLennan
- Department of Pathology and Laboratory Medicine, Institute for Pediatric Regenerative Medicine, Shriners Hospitals for Children of Northern California, School of Medicine, University of California Davis, Sacramento, CA 95817, USA;
| | | | - Federica Alice Maria Montanaro
- Child and Adolescent Neuropsychiatry Unit, Department of Neuroscience, Bambino Gesù Children’s Hospital, IRCCS, 00165 Rome, Italy;
- Department of Education, Psychology, Communication, University of Bari Aldo Moro, 70121 Bari, Italy
| | - Matthew W. Mosconi
- Schiefelbusch Institute for Life Span Studies, University of Kansas, Lawrence, KS 66045, USA;
- Clinical Child Psychology Program, University of Kansas, Lawrence, KS 66045, USA
- Kansas Center for Autism Research and Training (K-CART), University of Kansas, Lawrence, KS 66045, USA
| | - Sarah Nelson Potter
- RTI International, Research Triangle Park, NC 27709, USA; (J.E.H.); (S.N.P.); (M.R.); (A.W.)
| | - Melissa Raspa
- RTI International, Research Triangle Park, NC 27709, USA; (J.E.H.); (S.N.P.); (M.R.); (A.W.)
| | - Susan M. Rivera
- Department of Psychology, University of Maryland, College Park, MD 20742, USA;
| | - Katharine Shelly
- Department of Human Genetics, Emory University School of Medicine, Atlanta, GA 30322, USA; (E.G.A.); (P.J.); (K.S.)
| | - Peter K. Todd
- Department of Neurology, University of Michigan, 4148 BSRB, 109 Zina Pitcher Place, Ann Arbor, MI 48109, USA; (S.J.G.); (P.K.T.)
- Ann Arbor Veterans Administration Healthcare, Ann Arbor, MI 48105, USA
| | - Katarzyna Tutak
- Department of Gene Expression, Institute of Molecular Biology and Biotechnology, Adam Mickiewicz University, Uniwersytetu Poznańskiego 6, 61-614 Poznan, Poland; (A.B.); (K.T.)
| | - Jun Yi Wang
- Center for Mind and Brain, University of California Davis, Davis, CA 95618, USA;
| | - Anne Wheeler
- RTI International, Research Triangle Park, NC 27709, USA; (J.E.H.); (S.N.P.); (M.R.); (A.W.)
| | - Tri Indah Winarni
- Center for Biomedical Research (CEBIOR), Faculty of Medicine, Universitas Diponegoro, Semarang 502754, Central Java, Indonesia;
| | - Marwa Zafarullah
- Department of Biochemistry and Molecular Medicine, School of Medicine, University of California Davis, Sacramento, CA 95817, USA;
| | - Randi J. Hagerman
- MIND Institute, University of California Davis, Davis, CA 95817, USA; (B.D.); (D.H.); (V.M.-C.)
- Department of Pediatrics, School of Medicine, University of California Davis, Sacramento, CA 95817, USA
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Puri V, Kanojia N, Sharma A, Huanbutta K, Dheer D, Sangnim T. Natural product-based pharmacological studies for neurological disorders. Front Pharmacol 2022; 13:1011740. [PMID: 36419628 PMCID: PMC9676372 DOI: 10.3389/fphar.2022.1011740] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2022] [Accepted: 10/18/2022] [Indexed: 11/07/2023] Open
Abstract
Central nervous system (CNS) disorders and diseases are expected to rise sharply in the coming years, partly because of the world's aging population. Medicines for the treatment of the CNS have not been successfully made. Inadequate knowledge about the brain, pharmacokinetic and dynamic errors in preclinical studies, challenges with clinical trial design, complexity and variety of human brain illnesses, and variations in species are some potential scenarios. Neurodegenerative diseases (NDDs) are multifaceted and lack identifiable etiological components, and the drugs developed to treat them did not meet the requirements of those who anticipated treatments. Therefore, there is a great demand for safe and effective natural therapeutic adjuvants. For the treatment of NDDs and other memory-related problems, many herbal and natural items have been used in the Ayurvedic medical system. Anxiety, depression, Parkinson's, and Alzheimer's diseases (AD), as well as a plethora of other neuropsychiatric disorders, may benefit from the use of plant and food-derived chemicals that have antidepressant or antiepileptic properties. We have summarized the present level of knowledge about natural products based on topological evidence, bioinformatics analysis, and translational research in this review. We have also highlighted some clinical research or investigation that will help us select natural products for the treatment of neurological conditions. In the present review, we have explored the potential efficacy of phytoconstituents against neurological diseases. Various evidence-based studies and extensive recent investigations have been included, which will help pharmacologists reduce the progression of neuronal disease.
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Affiliation(s)
- Vivek Puri
- Chitkara School of Pharmacy, Chitkara University, Baddi, Himachal Pradesh, India
| | - Neha Kanojia
- Chitkara School of Pharmacy, Chitkara University, Baddi, Himachal Pradesh, India
| | - Ameya Sharma
- Chitkara School of Pharmacy, Chitkara University, Baddi, Himachal Pradesh, India
| | - Kampanart Huanbutta
- School of Pharmacy, Eastern Asia University, Rangsit, Pathum Thani, Thailand
| | - Divya Dheer
- Chitkara School of Pharmacy, Chitkara University, Baddi, Himachal Pradesh, India
| | - Tanikan Sangnim
- Faculty of Pharmaceutical Sciences, Burapha University, Muang, Chon Buri, Thailand
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Liu Y, Li H, Liu X, Wang B, Yang H, Wan B, Sun M, Xu X. Clinical and mechanism advances of neuronal intranuclear inclusion disease. Front Aging Neurosci 2022; 14:934725. [PMID: 36177481 PMCID: PMC9513122 DOI: 10.3389/fnagi.2022.934725] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2022] [Accepted: 08/22/2022] [Indexed: 11/13/2022] Open
Abstract
Due to the high clinical heterogeneity of neuronal intranuclear inclusion disease (NIID), it is easy to misdiagnose this condition and is considered to be a rare progressive neurodegenerative disease. More evidence demonstrates that NIID involves not only the central nervous system but also multiple systems of the body and shows a variety of symptoms, which makes a clinical diagnosis of NIID more difficult. This review summarizes the clinical symptoms in different systems and demonstrates that NIID is a multiple-system intranuclear inclusion disease. In addition, the core triad symptoms in the central nervous system, such as dementia, parkinsonism, and psychiatric symptoms, are proposed as an important clue for the clinical diagnosis of NIID. Recent studies have demonstrated that expanded GGC repeats in the 5′-untranslated region of the NOTCH2NLC gene are the cause of NIID. The genetic advances and possible underlying mechanisms of NIID (expanded GGC repeat-induced DNA damage, RNA toxicity, and polyglycine-NOTCH2NLC protein toxicity) are briefly summarized in this review. Interestingly, inflammatory cell infiltration and inflammation were observed in the affected tissues of patients with NIID. As a downstream pathological process of NIID, inflammation could be a therapeutic target for NIID.
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Affiliation(s)
- Yueqi Liu
- Department of Neurology, The First Affiliated Hospital of Soochow University, Suzhou, China
- Institute of Neuroscience, Soochow University, Suzhou, China
| | - Hao Li
- Department of Neurology, The First Affiliated Hospital of Soochow University, Suzhou, China
- Institute of Neuroscience, Soochow University, Suzhou, China
| | - Xuan Liu
- Department of Neurology, The First Affiliated Hospital of Soochow University, Suzhou, China
| | - Bin Wang
- Institute of Neuroscience, Soochow University, Suzhou, China
- Institute for Fetology, The First Affiliated Hospital of Soochow University, Suzhou, China
| | - Hao Yang
- Institute for Fetology, The First Affiliated Hospital of Soochow University, Suzhou, China
| | - Bo Wan
- Institute of Neuroscience, Soochow University, Suzhou, China
- Bo Wan,
| | - Miao Sun
- Institute for Fetology, The First Affiliated Hospital of Soochow University, Suzhou, China
- Miao Sun,
| | - Xingshun Xu
- Department of Neurology, The First Affiliated Hospital of Soochow University, Suzhou, China
- Institute of Neuroscience, Soochow University, Suzhou, China
- Jiangsu Key Laboratory of Neuropsychiatric Diseases, Soochow University, Suzhou, Jiangsu, China
- *Correspondence: Xingshun Xu,
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Yousuf A, Ahmed N, Qurashi A. Non-canonical DNA/RNA structures associated with the pathogenesis of Fragile X-associated tremor/ataxia syndrome and Fragile X syndrome. Front Genet 2022; 13:866021. [PMID: 36110216 PMCID: PMC9468596 DOI: 10.3389/fgene.2022.866021] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2022] [Accepted: 07/22/2022] [Indexed: 11/13/2022] Open
Abstract
Fragile X-associated tremor/ataxia syndrome (FXTAS) and fragile X syndrome (FXS) are primary examples of fragile X-related disorders (FXDs) caused by abnormal expansion of CGG repeats above a certain threshold in the 5′-untranslated region of the fragile X mental retardation (FMR1) gene. Both diseases have distinct clinical manifestations and molecular pathogenesis. FXTAS is a late-adult-onset neurodegenerative disorder caused by a premutation (PM) allele (CGG expansion of 55–200 repeats), resulting in FMR1 gene hyperexpression. On the other hand, FXS is a neurodevelopmental disorder that results from a full mutation (FM) allele (CGG expansions of ≥200 repeats) leading to heterochromatization and transcriptional silencing of the FMR1 gene. The main challenge is to determine how CGG repeat expansion affects the fundamentally distinct nature of FMR1 expression in FM and PM ranges. Abnormal CGG repeat expansions form a variety of non-canonical DNA and RNA structures that can disrupt various cellular processes and cause distinct effects in PM and FM alleles. Here, we review these structures and how they are related to underlying mutations and disease pathology in FXS and FXTAS. Finally, as new CGG expansions within the genome have been identified, it will be interesting to determine their implications in disease pathology and treatment.
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Kameyama S, Mizuguchi T, Doi H, Koyano S, Okubo M, Tada M, Shimizu H, Fukuda H, Tsuchida N, Uchiyama Y, Koshimizu E, Hamanaka K, Fujita A, Misawa K, Miyatake S, Kanai K, Tanaka F, Matsumoto N. Patients with biallelic GGC repeat expansions in NOTCH2NLC exhibiting a typical neuronal intranuclear inclusion disease phenotype. Genomics 2022; 114:110469. [PMID: 36041634 DOI: 10.1016/j.ygeno.2022.110469] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2022] [Revised: 08/16/2022] [Accepted: 08/26/2022] [Indexed: 11/27/2022]
Abstract
We report two patients with autosomal dominant neuronal intranuclear inclusion disease (NIID) harboring the biallelic GGC repeat expansion in NOTCH2NLC to uncover the impact of repeat expansion zygosity on the clinical phenotype. The zygosity of the entire NOTCH2NLC GGC repeat expansion and DNA methylation were comprehensively evaluated using fluorescent amplicon length PCR (AL-PCR), Southern blotting and targeted long-read sequencing, and detailed genetic/epigenetic and clinical features were described. In AL-PCR, we could not recognize the wild-type allele in both patients. Targeted long-read sequencing revealed that one patient harbored a homozygous repeat expansion. The other patient harbored compound heterozygous repeat expansions. The GGC repeats and the nearest CpG island were hypomethylated in all expanded alleles in both patients. Both patients harboring the biallelic GGC repeat expansion showed a typical dementia-dominant NIID phenotype. In conclusion, the biallelic GGC repeat expansion in two typical NIID patients indicated that NOTCH2NLC-related diseases could be completely dominant.
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Affiliation(s)
- Shinichi Kameyama
- Department of Human Genetics, Yokohama City University Graduate School of Medicine, Yokohama 236-0004, Japan; Department of Pathology, Keio University School of Medicine, Tokyo 160-8582, Japan
| | - Takeshi Mizuguchi
- Department of Human Genetics, Yokohama City University Graduate School of Medicine, Yokohama 236-0004, Japan.
| | - Hiroshi Doi
- Department of Neurology and Stroke Medicine, Yokohama City University Graduate School of Medicine, Yokohama 236-0004, Japan
| | - Shigeru Koyano
- Department of Neurology, Yokohama Minami Kyosai Hospital, Yokohama 236-0037, Japan
| | - Masaki Okubo
- Department of Neurology and Stroke Medicine, Yokohama City University Graduate School of Medicine, Yokohama 236-0004, Japan
| | - Mikiko Tada
- Department of Neurology and Stroke Medicine, Yokohama City University Graduate School of Medicine, Yokohama 236-0004, Japan
| | - Hiroshi Shimizu
- Department of Pathology, Brain Research Institute, Niigata University, Niigata 951-8585, Japan
| | - Hiromi Fukuda
- Department of Human Genetics, Yokohama City University Graduate School of Medicine, Yokohama 236-0004, Japan; Department of Neurology and Stroke Medicine, Yokohama City University Graduate School of Medicine, Yokohama 236-0004, Japan
| | - Naomi Tsuchida
- Department of Human Genetics, Yokohama City University Graduate School of Medicine, Yokohama 236-0004, Japan; Department of Rare Disease Genomics, Yokohama City University Hospital, Yokohama 236-0004, Japan
| | - Yuri Uchiyama
- Department of Human Genetics, Yokohama City University Graduate School of Medicine, Yokohama 236-0004, Japan; Department of Rare Disease Genomics, Yokohama City University Hospital, Yokohama 236-0004, Japan
| | - Eriko Koshimizu
- Department of Human Genetics, Yokohama City University Graduate School of Medicine, Yokohama 236-0004, Japan
| | - Kohei Hamanaka
- Department of Human Genetics, Yokohama City University Graduate School of Medicine, Yokohama 236-0004, Japan
| | - Atsushi Fujita
- Department of Human Genetics, Yokohama City University Graduate School of Medicine, Yokohama 236-0004, Japan
| | - Kazuharu Misawa
- Department of Human Genetics, Yokohama City University Graduate School of Medicine, Yokohama 236-0004, Japan
| | - Satoko Miyatake
- Department of Human Genetics, Yokohama City University Graduate School of Medicine, Yokohama 236-0004, Japan; Clinical Genetics Department, Yokohama City University Hospital, Yokohama 236-0004, Japan
| | - Kazuaki Kanai
- Department of Neurology, Fukushima Medical University School of Medicine, Fukushima 960-1295, Japan
| | - Fumiaki Tanaka
- Department of Neurology and Stroke Medicine, Yokohama City University Graduate School of Medicine, Yokohama 236-0004, Japan
| | - Naomichi Matsumoto
- Department of Human Genetics, Yokohama City University Graduate School of Medicine, Yokohama 236-0004, Japan.
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9
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Liufu T, Zheng Y, Yu J, Yuan Y, Wang Z, Deng J, Hong D. The polyG diseases: a new disease entity. Acta Neuropathol Commun 2022; 10:79. [PMID: 35642014 PMCID: PMC9153130 DOI: 10.1186/s40478-022-01383-y] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2022] [Accepted: 05/16/2022] [Indexed: 12/20/2022] Open
Abstract
Recently, inspired by the similar clinical and pathological features shared with fragile X-associated tremor/ataxia syndrome (FXTAS), abnormal expansion of CGG repeats in the 5' untranslated region has been found in neuronal intranuclear inclusion disease (NIID), oculopharyngeal myopathy with leukoencephalopathy (OPML), and oculopharyngodistal myopathy (OPDMs). Although the upstream open reading frame has not been elucidated in OPML and OPDMs, polyglycine (polyG) translated by expanded CGG repeats is reported to be as a primary pathogenesis in FXTAS and NIID. Collectively, these findings indicate a new disease entity, the polyG diseases. In this review, we state the common clinical manifestations, pathological features, mechanisms, and potential therapies in these diseases, and provide preliminary opinions about future research in polyG diseases.
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Affiliation(s)
- Tongling Liufu
- Department of Neurology, Peking University First Hospital, Beijing, China
| | - Yilei Zheng
- Department of Neurology, The First Affiliated Hospital of Nanchang University, Nanchang, China
| | - Jiaxi Yu
- Department of Neurology, Peking University First Hospital, Beijing, China
| | - Yun Yuan
- Department of Neurology, Peking University First Hospital, Beijing, China
| | - Zhaoxia Wang
- Department of Neurology, Peking University First Hospital, Beijing, China.,Beijing Key Laboratory of Neurovascular Disease Discovery, Beijing, China
| | - Jianwen Deng
- Department of Neurology, Peking University First Hospital, Beijing, China. .,Beijing Key Laboratory of Neurovascular Disease Discovery, Beijing, China.
| | - Daojun Hong
- Department of Neurology, The First Affiliated Hospital of Nanchang University, Nanchang, China. .,Department of Medical Genetics, The First Affiliated Hospital of Nanchang University, Nanchang, China.
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10
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Boivin M, Charlet-Berguerand N. Trinucleotide CGG Repeat Diseases: An Expanding Field of Polyglycine Proteins? Front Genet 2022; 13:843014. [PMID: 35295941 PMCID: PMC8918734 DOI: 10.3389/fgene.2022.843014] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2021] [Accepted: 01/31/2022] [Indexed: 12/30/2022] Open
Abstract
Microsatellites are repeated DNA sequences of 3–6 nucleotides highly variable in length and sequence and that have important roles in genomes regulation and evolution. However, expansion of a subset of these microsatellites over a threshold size is responsible of more than 50 human genetic diseases. Interestingly, some of these disorders are caused by expansions of similar sequences, sizes and localizations and present striking similarities in clinical manifestations and histopathological features, which suggest a common mechanism of disease. Notably, five identical CGG repeat expansions, but located in different genes, are the causes of fragile X-associated tremor/ataxia syndrome (FXTAS), neuronal intranuclear inclusion disease (NIID), oculopharyngodistal myopathy type 1 to 3 (OPDM1-3) and oculopharyngeal myopathy with leukoencephalopathy (OPML), which are neuromuscular and neurodegenerative syndromes with overlapping symptoms and similar histopathological features, notably the presence of characteristic eosinophilic ubiquitin-positive intranuclear inclusions. In this review we summarize recent finding in neuronal intranuclear inclusion disease and FXTAS, where the causing CGG expansions were found to be embedded within small upstream ORFs (uORFs), resulting in their translation into novel proteins containing a stretch of polyglycine (polyG). Importantly, expression of these polyG proteins is toxic in animal models and is sufficient to reproduce the formation of ubiquitin-positive intranuclear inclusions. These data suggest the existence of a novel class of human genetic pathology, the polyG diseases, and question whether a similar mechanism may exist in other diseases, notably in OPDM and OPML.
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11
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Fukuda H, Yamaguchi D, Nyquist K, Yabuki Y, Miyatake S, Uchiyama Y, Hamanaka K, Saida K, Koshimizu E, Tsuchida N, Fujita A, Mitsuhashi S, Ohbo K, Satake Y, Sone J, Doi H, Morihara K, Okamoto T, Takahashi Y, Wenger AM, Shioda N, Tanaka F, Matsumoto N, Mizuguchi T. Father-to-offspring transmission of extremely long NOTCH2NLC repeat expansions with contractions: genetic and epigenetic profiling with long-read sequencing. Clin Epigenetics 2021; 13:204. [PMID: 34774111 PMCID: PMC8590777 DOI: 10.1186/s13148-021-01192-5] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2021] [Accepted: 10/27/2021] [Indexed: 12/11/2022] Open
Abstract
Background GGC repeat expansions in NOTCH2NLC are associated with neuronal intranuclear inclusion disease. Very recently, asymptomatic carriers with NOTCH2NLC repeat expansions were reported. In these asymptomatic individuals, the CpG island in NOTCH2NLC is hypermethylated, suggesting that two factors repeat length and DNA methylation status should be considered to evaluate pathogenicity. Long-read sequencing can be used to simultaneously profile genomic and epigenomic alterations. We analyzed four sporadic cases with NOTCH2NLC repeat expansion and their phenotypically normal parents. The native genomic DNA that retains base modification was sequenced on a per-trio basis using both PacBio and Oxford Nanopore long-read sequencing technologies. A custom workflow was developed to evaluate DNA modifications. With these two technologies combined, long-range DNA methylation information was integrated with complete repeat DNA sequences to investigate the genetic origins of expanded GGC repeats in these sporadic cases. Results In all four families, asymptomatic fathers had longer expansions (median: 522, 390, 528 and 650 repeats) compared with their affected offspring (median: 93, 117, 162 and 140 repeats, respectively). These expansions are much longer than the disease-causing range previously reported (in general, 41–300 repeats). Repeat lengths were extremely variable in the father, suggesting somatic mosaicism. Instability is more frequent in alleles with uninterrupted pure GGCs. Single molecule epigenetic analysis revealed complex DNA methylation patterns and epigenetic heterogeneity. We identified an aberrant gain-of-methylation region (2.2 kb in size beyond the CpG island and GGC repeats) in asymptomatic fathers. This methylated region was unmethylated in the normal allele with bilateral transitional zones with both methylated and unmethylated CpG dinucleotides, which may be protected from methylation to ensure NOTCH2NLC expression. Conclusions We clearly demonstrate that the four sporadic NOTCH2NLC-related cases are derived from the paternal GGC repeat contraction associated with demethylation. The entire genetic and epigenetic landscape of the NOTCH2NLC region was uncovered using the custom workflow of long-read sequence data, demonstrating the utility of this method for revealing epigenetic/mutational changes in repetitive elements, which are difficult to characterize by conventional short-read/bisulfite sequencing methods. Our approach should be useful for biomedical research, aiding the discovery of DNA methylation abnormalities through the entire genome. Supplementary Information The online version contains supplementary material available at 10.1186/s13148-021-01192-5.
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Affiliation(s)
- Hiromi Fukuda
- Department of Human Genetics, Yokohama City University Graduate School of Medicine, 3-9 Fukuura, Kanazawa-ku, Yokohama, 236-0004, Japan.,Department of Neurology and Stroke Medicine, Yokohama City University Graduate School of Medicine, Yokohama, Japan
| | | | | | - Yasushi Yabuki
- Department of Genomic Neurology, Institute of Molecular Embryology and Genetics (IMEG), Kumamoto University, Kumamoto, Japan.,Graduate School of Pharmaceutical Sciences, Kumamoto University, Kumamoto, Japan
| | - Satoko Miyatake
- Department of Human Genetics, Yokohama City University Graduate School of Medicine, 3-9 Fukuura, Kanazawa-ku, Yokohama, 236-0004, Japan.,Clinical Genetics Department, Yokohama City University Hospital, Yokohama, Japan
| | - Yuri Uchiyama
- Department of Human Genetics, Yokohama City University Graduate School of Medicine, 3-9 Fukuura, Kanazawa-ku, Yokohama, 236-0004, Japan.,Department of Rare Disease Genomics, Yokohama City University Hospital, Yokohama, Japan
| | - Kohei Hamanaka
- Department of Human Genetics, Yokohama City University Graduate School of Medicine, 3-9 Fukuura, Kanazawa-ku, Yokohama, 236-0004, Japan
| | - Ken Saida
- Department of Human Genetics, Yokohama City University Graduate School of Medicine, 3-9 Fukuura, Kanazawa-ku, Yokohama, 236-0004, Japan
| | - Eriko Koshimizu
- Department of Human Genetics, Yokohama City University Graduate School of Medicine, 3-9 Fukuura, Kanazawa-ku, Yokohama, 236-0004, Japan
| | - Naomi Tsuchida
- Department of Human Genetics, Yokohama City University Graduate School of Medicine, 3-9 Fukuura, Kanazawa-ku, Yokohama, 236-0004, Japan.,Department of Rare Disease Genomics, Yokohama City University Hospital, Yokohama, Japan
| | - Atsushi Fujita
- Department of Human Genetics, Yokohama City University Graduate School of Medicine, 3-9 Fukuura, Kanazawa-ku, Yokohama, 236-0004, Japan
| | - Satomi Mitsuhashi
- Department of Genomic Function and Diversity, Medical Research Institute Tokyo Medical and Dental University, Tokyo, Japan
| | - Kazuyuki Ohbo
- Department of Histology and Cell Biology, Yokohama City University Graduate School of Medicine, Yokohama, Japan
| | - Yuki Satake
- Department of Neurology, Yokkaichi Municipal Hospital, Yokkaichi, Japan
| | - Jun Sone
- Department of Neuropathology, Institute for Medical Science of Aging, Aichi Medical University, Nagakute, Japan.,Department of Neurology, National Hospital Organization Suzuka National Hospital, Suzuka, Japan
| | - Hiroshi Doi
- Department of Neurology and Stroke Medicine, Yokohama City University Graduate School of Medicine, Yokohama, Japan
| | - Keisuke Morihara
- Department of Neurology and Stroke Medicine, Yokohama City University Graduate School of Medicine, Yokohama, Japan
| | - Tomoko Okamoto
- Department of Neurology, National Center Hospital, National Center of Neurology and Psychiatry, Tokyo, Japan
| | - Yuji Takahashi
- Department of Neurology, National Center Hospital, National Center of Neurology and Psychiatry, Tokyo, Japan
| | | | - Norifumi Shioda
- Department of Genomic Neurology, Institute of Molecular Embryology and Genetics (IMEG), Kumamoto University, Kumamoto, Japan.,Graduate School of Pharmaceutical Sciences, Kumamoto University, Kumamoto, Japan
| | - Fumiaki Tanaka
- Department of Neurology and Stroke Medicine, Yokohama City University Graduate School of Medicine, Yokohama, Japan
| | - Naomichi Matsumoto
- Department of Human Genetics, Yokohama City University Graduate School of Medicine, 3-9 Fukuura, Kanazawa-ku, Yokohama, 236-0004, Japan.
| | - Takeshi Mizuguchi
- Department of Human Genetics, Yokohama City University Graduate School of Medicine, 3-9 Fukuura, Kanazawa-ku, Yokohama, 236-0004, Japan.
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12
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Huang XR, Tang BS, Jin P, Guo JF. The Phenotypes and Mechanisms of NOTCH2NLC-Related GGC Repeat Expansion Disorders: a Comprehensive Review. Mol Neurobiol 2021; 59:523-534. [PMID: 34718964 DOI: 10.1007/s12035-021-02616-2] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2021] [Accepted: 10/24/2021] [Indexed: 01/11/2023]
Abstract
The human-specific gene NOTCH2NLC is primarily expressed in radial glial cells and plays an important role in neuronal differentiation and cortical neurogenesis. Increasing studies were conducted to verify the relationship between NOTCH2NLC gene and many neurological diseases, such as neuronal intranuclear inclusion disease, essential tremor, multiple system atrophy, Parkinson's disease, Alzheimer's disease, and even oculopharyngodistal myopathy. Thus, we support the concept, NOTCH2NLC-related GGC repeat expansion disorders (NRED), to summarize all diseases with the GGC repeat expansion in the 5'UTR of NOTCH2NLC gene, regardless of their various clinical phenotypes. Here, we discuss the reported cases to analyze the clinical features of NOTCH2NLC-related GGC repeat expansion disorders, including dementia, parkinsonism, peripheral neuropathy and myopathy, leukoencephalopathy, and essential tremor. In addition, we outline radiological and pathological manifestations of NOTCH2NLC-related GGC repeat expansion disorders, and then present possible mechanisms, such as toxic polyG protein, toxic repeat RNA, the GGC repeat size, and the size and types of trinucleotide interruption. Therefore, this review provides a systematic description of NOTCH2NLC-related GGC repeat expansion disorders and emphasizes the significance for understanding this type of repeat expansion disease.
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Affiliation(s)
- Xiu-Rong Huang
- Department of Neurology, Xiangya Hospital, Central South University, Changsha, 410008, Hunan, China
| | - Bei-Sha Tang
- Department of Neurology, Xiangya Hospital, Central South University, Changsha, 410008, Hunan, China.,National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Central South University, Changsha, Hunan, China.,Centre for Medical Genetics and Hunan Key Laboratory of Medical Genetics, School of Life Sciences, Central South University, Changsha, Hunan, China.,Key Laboratory of Hunan Province in Neurodegenerative Disorders, Central South University, Changsha, Hunan, China
| | - Peng Jin
- Department of Human Genetics, Emory University School of Medicine, Atlanta, GA, USA
| | - Ji-Feng Guo
- Department of Neurology, Xiangya Hospital, Central South University, Changsha, 410008, Hunan, China. .,National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Central South University, Changsha, Hunan, China. .,Centre for Medical Genetics and Hunan Key Laboratory of Medical Genetics, School of Life Sciences, Central South University, Changsha, Hunan, China. .,Key Laboratory of Hunan Province in Neurodegenerative Disorders, Central South University, Changsha, Hunan, China.
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13
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Molecular Pathogenesis and Peripheral Monitoring of Adult Fragile X-Associated Syndromes. Int J Mol Sci 2021; 22:ijms22168368. [PMID: 34445074 PMCID: PMC8395059 DOI: 10.3390/ijms22168368] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2021] [Revised: 07/29/2021] [Accepted: 07/30/2021] [Indexed: 12/16/2022] Open
Abstract
Abnormal trinucleotide expansions cause rare disorders that compromise quality of life and, in some cases, lifespan. In particular, the expansions of the CGG-repeats stretch at the 5’-UTR of the Fragile X Mental Retardation 1 (FMR1) gene have pleiotropic effects that lead to a variety of Fragile X-associated syndromes: the neurodevelopmental Fragile X syndrome (FXS) in children, the late-onset neurodegenerative disorder Fragile X-associated tremor-ataxia syndrome (FXTAS) that mainly affects adult men, the Fragile X-associated primary ovarian insufficiency (FXPOI) in adult women, and a variety of psychiatric and affective disorders that are under the term of Fragile X-associated neuropsychiatric disorders (FXAND). In this review, we will describe the pathological mechanisms of the adult “gain-of-function” syndromes that are mainly caused by the toxic actions of CGG RNA and FMRpolyG peptide. There have been intensive attempts to identify reliable peripheral biomarkers to assess disease progression and onset of specific pathological traits. Mitochondrial dysfunction, altered miRNA expression, endocrine system failure, and impairment of the GABAergic transmission are some of the affectations that are susceptible to be tracked using peripheral blood for monitoring of the motor, cognitive, psychiatric and reproductive impairment of the CGG-expansion carriers. We provided some illustrative examples from our own cohort. Understanding the association between molecular pathogenesis and biomarkers dynamics will improve effective prognosis and clinical management of CGG-expansion carriers.
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