Review

. 2023 Sep 21;12(18):2330.

doi: 10.3390/cells12182330.

Insight and Recommendations for Fragile X-Premutation-Associated Conditions from the Fifth International Conference on FMR1 Premutation

Flora Tassone^{1

2}, Dragana Protic^{3

4}, Emily Graves Allen⁵, Alison D Archibald^{6

7

8}, Anna Baud⁹, Ted W Brown^{10

11

12}, Dejan B Budimirovic^{13

14}, Jonathan Cohen¹⁵, Brett Dufour^{2

16}, Rachel Eiges¹⁷, Nicola Elvassore^{18

19}, Lidia V Gabis^{20

21}, Samantha J Grudzien^{22

23

24}, Deborah A Hall²⁵, David Hessl^{2

26}, Abigail Hogan²⁷, Jessica Ezzell Hunter²⁸, Peng Jin⁵, Poonnada Jiraanont²⁹, Jessica Klusek²⁷, R Frank Kooy³⁰, Claudine M Kraan^{7

31}, Cecilia Laterza^{18

19}, Andrea Lee³², Karen Lipworth¹¹, Molly Losh³³, Danuta Loesch³⁴, Reymundo Lozano³⁵, Marsha R Mailick³⁶, Apostolos Manolopoulos³⁷, Veronica Martinez-Cerdeno^{2

16}, Yingratana McLennan¹⁶, Robert M Miller³⁸, Federica Alice Maria Montanaro^{39

40}, Matthew W Mosconi^{41

42

43}, Sarah Nelson Potter²⁸, Melissa Raspa²⁸, Susan M Rivera⁴⁴, Katharine Shelly⁵, Peter K Todd^{22

45}, Katarzyna Tutak⁹, Jun Yi Wang⁴⁶, Anne Wheeler²⁸, Tri Indah Winarni⁴⁷, Marwa Zafarullah¹, Randi J Hagerman^{2

48}

Affiliations

¹ Department of Biochemistry and Molecular Medicine, School of Medicine, University of California Davis, Sacramento, CA 95817, USA.
² MIND Institute, University of California Davis, Davis, CA 95817, USA.
³ Department of Pharmacology, Clinical Pharmacology and Toxicology, Faculty of Medicine, University of Belgrade, 11129 Belgrade, Serbia.
⁴ Fragile X Clinic, Special Hospital for Cerebral Palsy and Developmental Neurology, 11040 Belgrade, Serbia.
⁵ Department of Human Genetics, Emory University School of Medicine, Atlanta, GA 30322, USA.
⁶ Victorian Clinical Genetics Services, Royal Children's Hospital, Melbourne, VIC 3052, Australia.
⁷ Department of Paediatrics, Faculty of Medicine, Dentistry and Health Sciences, The University of Melbourne, Melbourne, VIC 3052, Australia.
⁸ Genomics in Society Group, Murdoch Children's Research Institute, Royal Children's Hospital, Melbourne, VIC 3052, Australia.
⁹ Department of Gene Expression, Institute of Molecular Biology and Biotechnology, Adam Mickiewicz University, Uniwersytetu Poznańskiego 6, 61-614 Poznan, Poland.
¹⁰ Central Clinical School, University of Sydney, Sydney, NSW 2006, Australia.
¹¹ Fragile X Association of Australia, Brookvale, NSW 2100, Australia.
¹² NYS Institute for Basic Research in Developmental Disabilities, New York, NY 10314, USA.
¹³ Department of Psychiatry, Fragile X Clinic, Kennedy Krieger Institute, Baltimore, MD 21205, USA.
¹⁴ Department of Psychiatry & Behavioral Sciences-Child Psychiatry, School of Medicine, Johns Hopkins University, Baltimore, MD 21205, USA.
¹⁵ Fragile X Alliance Clinic, Melbourne, VIC 3161, Australia.
¹⁶ 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.
¹⁷ Stem Cell Research Laboratory, Medical Genetics Institute, Shaare Zedek Medical Center Affiliated with the Hebrew University School of Medicine, Jerusalem 91031, Israel.
¹⁸ Veneto Institute of Molecular Medicine (VIMM), 35129 Padova, Italy.
¹⁹ Department of Industrial Engineering, University of Padova, 35131 Padova, Italy.
²⁰ Keshet Autism Center Maccabi Wolfson, Holon 5822012, Israel.
²¹ Faculty of Medicine, Tel-Aviv University, Tel Aviv 6997801, Israel.
²² Department of Neurology, University of Michigan, 4148 BSRB, 109 Zina Pitcher Place, Ann Arbor, MI 48109, USA.
²³ Neuroscience Graduate Program, University of Michigan, Ann Arbor, MI 48109, USA.
²⁴ Department of Computational Medicine and Bioinformatics, University of Michigan, Ann Arbor, MI 48109, USA.
²⁵ Department of Neurological Sciences, Rush University, Chicago, IL 60612, USA.
²⁶ Department of Psychiatry and Behavioral Sciences, School of Medicine, University of California Davis, Sacramento, CA 95817, USA.
²⁷ Department of Communication Sciences and Disorders, Arnold School of Public Health, University of South Carolina, Columbia, SC 29208, USA.
²⁸ RTI International, Research Triangle Park, NC 27709, USA.
²⁹ Faculty of Medicine, King Mongkut's Institute of Technology Ladkrabang, Bangkok 10520, Thailand.
³⁰ Department of Medical Genetics, University of Antwerp, 2000 Antwerp, Belgium.
³¹ Diagnosis and Development, Murdoch Children's Research Institute, Melbourne, VIC 3052, Australia.
³² Fragile X New Zealand, Nelson 7040, New Zealand.
³³ Roxelyn and Richard Pepper Department of Communication Sciences and Disorders, Northwestern University, Evanston, IL 60201, USA.
³⁴ School of Psychology and Public Health, La Trobe University, Melbourne, VIC 3086, Australia.
³⁵ Departments of Genetics and Genomic Sciences and Pediatrics, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA.
³⁶ Waisman Center, University of Wisconsin-Madison, Madison, WI 53705, USA.
³⁷ Intramural Research Program, Laboratory of Clinical Investigation, National Institute on Aging, Baltimore, MD 21224, USA.
³⁸ National Fragile X Foundation, Washington, DC 20005, USA.
³⁹ Child and Adolescent Neuropsychiatry Unit, Department of Neuroscience, Bambino Gesù Children's Hospital, IRCCS, 00165 Rome, Italy.
⁴⁰ Department of Education, Psychology, Communication, University of Bari Aldo Moro, 70121 Bari, Italy.
⁴¹ Schiefelbusch Institute for Life Span Studies, University of Kansas, Lawrence, KS 66045, USA.
⁴² Clinical Child Psychology Program, University of Kansas, Lawrence, KS 66045, USA.
⁴³ Kansas Center for Autism Research and Training (K-CART), University of Kansas, Lawrence, KS 66045, USA.
⁴⁴ Department of Psychology, University of Maryland, College Park, MD 20742, USA.
⁴⁵ Ann Arbor Veterans Administration Healthcare, Ann Arbor, MI 48105, USA.
⁴⁶ Center for Mind and Brain, University of California Davis, Davis, CA 95618, USA.
⁴⁷ Center for Biomedical Research (CEBIOR), Faculty of Medicine, Universitas Diponegoro, Semarang 502754, Central Java, Indonesia.
⁴⁸ Department of Pediatrics, School of Medicine, University of California Davis, Sacramento, CA 95817, USA.

PMID: 37759552
PMCID: PMC10529056
DOI: 10.3390/cells12182330

Review

Insight and Recommendations for Fragile X-Premutation-Associated Conditions from the Fifth International Conference on FMR1 Premutation

Flora Tassone et al. Cells. 2023.

. 2023 Sep 21;12(18):2330.

doi: 10.3390/cells12182330.

Authors

Affiliations

¹ Department of Biochemistry and Molecular Medicine, School of Medicine, University of California Davis, Sacramento, CA 95817, USA.
² MIND Institute, University of California Davis, Davis, CA 95817, USA.
³ Department of Pharmacology, Clinical Pharmacology and Toxicology, Faculty of Medicine, University of Belgrade, 11129 Belgrade, Serbia.
⁴ Fragile X Clinic, Special Hospital for Cerebral Palsy and Developmental Neurology, 11040 Belgrade, Serbia.
⁵ Department of Human Genetics, Emory University School of Medicine, Atlanta, GA 30322, USA.
⁶ Victorian Clinical Genetics Services, Royal Children's Hospital, Melbourne, VIC 3052, Australia.
⁷ Department of Paediatrics, Faculty of Medicine, Dentistry and Health Sciences, The University of Melbourne, Melbourne, VIC 3052, Australia.
⁸ Genomics in Society Group, Murdoch Children's Research Institute, Royal Children's Hospital, Melbourne, VIC 3052, Australia.
⁹ Department of Gene Expression, Institute of Molecular Biology and Biotechnology, Adam Mickiewicz University, Uniwersytetu Poznańskiego 6, 61-614 Poznan, Poland.
¹⁰ Central Clinical School, University of Sydney, Sydney, NSW 2006, Australia.
¹¹ Fragile X Association of Australia, Brookvale, NSW 2100, Australia.
¹² NYS Institute for Basic Research in Developmental Disabilities, New York, NY 10314, USA.
¹³ Department of Psychiatry, Fragile X Clinic, Kennedy Krieger Institute, Baltimore, MD 21205, USA.
¹⁴ Department of Psychiatry & Behavioral Sciences-Child Psychiatry, School of Medicine, Johns Hopkins University, Baltimore, MD 21205, USA.
¹⁵ Fragile X Alliance Clinic, Melbourne, VIC 3161, Australia.
¹⁶ 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.
¹⁷ Stem Cell Research Laboratory, Medical Genetics Institute, Shaare Zedek Medical Center Affiliated with the Hebrew University School of Medicine, Jerusalem 91031, Israel.
¹⁸ Veneto Institute of Molecular Medicine (VIMM), 35129 Padova, Italy.
¹⁹ Department of Industrial Engineering, University of Padova, 35131 Padova, Italy.
²⁰ Keshet Autism Center Maccabi Wolfson, Holon 5822012, Israel.
²¹ Faculty of Medicine, Tel-Aviv University, Tel Aviv 6997801, Israel.
²² Department of Neurology, University of Michigan, 4148 BSRB, 109 Zina Pitcher Place, Ann Arbor, MI 48109, USA.
²³ Neuroscience Graduate Program, University of Michigan, Ann Arbor, MI 48109, USA.
²⁴ Department of Computational Medicine and Bioinformatics, University of Michigan, Ann Arbor, MI 48109, USA.
²⁵ Department of Neurological Sciences, Rush University, Chicago, IL 60612, USA.
²⁶ Department of Psychiatry and Behavioral Sciences, School of Medicine, University of California Davis, Sacramento, CA 95817, USA.
²⁷ Department of Communication Sciences and Disorders, Arnold School of Public Health, University of South Carolina, Columbia, SC 29208, USA.
²⁸ RTI International, Research Triangle Park, NC 27709, USA.
²⁹ Faculty of Medicine, King Mongkut's Institute of Technology Ladkrabang, Bangkok 10520, Thailand.
³⁰ Department of Medical Genetics, University of Antwerp, 2000 Antwerp, Belgium.
³¹ Diagnosis and Development, Murdoch Children's Research Institute, Melbourne, VIC 3052, Australia.
³² Fragile X New Zealand, Nelson 7040, New Zealand.
³³ Roxelyn and Richard Pepper Department of Communication Sciences and Disorders, Northwestern University, Evanston, IL 60201, USA.
³⁴ School of Psychology and Public Health, La Trobe University, Melbourne, VIC 3086, Australia.
³⁵ Departments of Genetics and Genomic Sciences and Pediatrics, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA.
³⁶ Waisman Center, University of Wisconsin-Madison, Madison, WI 53705, USA.
³⁷ Intramural Research Program, Laboratory of Clinical Investigation, National Institute on Aging, Baltimore, MD 21224, USA.
³⁸ National Fragile X Foundation, Washington, DC 20005, USA.
³⁹ Child and Adolescent Neuropsychiatry Unit, Department of Neuroscience, Bambino Gesù Children's Hospital, IRCCS, 00165 Rome, Italy.
⁴⁰ Department of Education, Psychology, Communication, University of Bari Aldo Moro, 70121 Bari, Italy.
⁴¹ Schiefelbusch Institute for Life Span Studies, University of Kansas, Lawrence, KS 66045, USA.
⁴² Clinical Child Psychology Program, University of Kansas, Lawrence, KS 66045, USA.
⁴³ Kansas Center for Autism Research and Training (K-CART), University of Kansas, Lawrence, KS 66045, USA.
⁴⁴ Department of Psychology, University of Maryland, College Park, MD 20742, USA.
⁴⁵ Ann Arbor Veterans Administration Healthcare, Ann Arbor, MI 48105, USA.
⁴⁶ Center for Mind and Brain, University of California Davis, Davis, CA 95618, USA.
⁴⁷ Center for Biomedical Research (CEBIOR), Faculty of Medicine, Universitas Diponegoro, Semarang 502754, Central Java, Indonesia.
⁴⁸ Department of Pediatrics, School of Medicine, University of California Davis, Sacramento, CA 95817, USA.

PMID: 37759552
PMCID: PMC10529056
DOI: 10.3390/cells12182330

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.

Keywords: FMR1 molecular and clinical; FMR1 premutation; FXAND; FXPAC; FXPOI; FXTAS.

PubMed Disclaimer

Conflict of interest statement

The authors declare no conflict of interest.

Figures

**Figure 1**
Molecular mechanisms leading to *FMR1*-PM-associated conditions. Three nonexclusive models are proposed for how CGG repeats contribute to the pathogenesis of PM conditions, including FXTAS. First, the cotranscriptional R-loop formation, which compromises genomic stability and triggers a DNA-damage response that can activate inflammatory cascades [116,117]. Second, CGG-repeat RNAs can elicit a gain-of-function toxicity through RNA gelation into nuclear foci and sequestration of various rCGG-repeat-binding proteins, leading to their functional depletion [25,26]. Third, repeat-associated non-AUG (RAN)-initiated translation generates potentially toxic proteins that accumulate within intranuclear neuronal inclusions in FXTAS patients. The relative contribution from each mechanism to downstream sequelae, such as mitochondrial dysfunction and neuronal death, and their potential synergies in disease pathogenesis, are areas of ongoing research in the field. Adapted from [118].

**Figure 2**
FXPAC involvement across the lifespan.

**Figure 3**
(a–c) H&E and ubiquitin staining (brown). Inclusions in astrocytes (a), neurons (b), and Purkinje cells (c); (d) H&E. White-matter disease in cerebellum; (e) Cortical atrophy and venrticulomegalia; (f) Perl’s staining. Iron deposition in capillaries; (g,h) Iba1 staining. Activated microglia; (i,k) GFAP staining. Activated astrocytes; (j) Iba1 staining. Senescent microglia; (l) H&E. Microbleeding; (m,n) H&E and ubiquitin staining (brown). Inclusions in endothelial cells. Arrows and asterisks are indicating the pathology of interest. Arrowhead in (c) points to nucleolus.

**Figure 4**
Lived experience perspective. Results from an anonymous Survey Monkey questionnaire distributed via email to the member based of Fragile X New Zealand (n = 38). (a) Binary data (blue = yes; gray = no); (b) Preferred terminology by survey respondents; (c,d). Example quotes in response to query about (c) what is helpful in research and (d) what is unhelpful in research.

**Figure 5**
Lived experience perspectives from member based of NFXF and FXAA. (a) Results from an anonymous Survey Monkey questionnaire distributed via email to the member based of NFXF and FXAA (n = 255); (b) Example quotes.

**Figure 6**
Attendees at the 5th International Conference on *FMR1* Premutation.

See this image and copyright information in PMC

References

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Insight and Recommendations for Fragile X-Premutation-Associated Conditions from the Fifth International Conference on FMR1 Premutation

Affiliations

Insight and Recommendations for Fragile X-Premutation-Associated Conditions from the Fifth International Conference on FMR1 Premutation

Authors

Affiliations

Abstract

Conflict of interest statement

Figures

References

Publication types

MeSH terms

Substances

Supplementary concepts

Grants and funding

LinkOut - more resources

Full Text Sources

Medical

Miscellaneous