National Fragile X Foundation

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.

The pandemic caused by the spread of the coronavirus disease (COVID-19), beginning in early 2020, had an impact beyond anything experienced in recent history. People with Fragile X Syndrome (FXS), the leading known heritable cause of ASD and intellectual disability, were uniquely vulnerable to pandemic-related changes. This study surveyed parent perspectives of the impact on 33 school-aged children with FXS across daily living skills, education, therapies, behaviors, health visits, and mask wearing. Academic performance was perceived to have decreased in most of the children (58%). Students in online school had the most reports of decline and those in person had the most reported improvement. Parents were significantly more satisfied with services that remained in person compared to those delivered online or in hybrid settings. Additionally, depression (75%), sleep problems (80%), attention problems (73%), and social skills (61%) were reported to have worsened the most. Parents reported that in addition to continuing with a structured schedule, the most helpful strategies were increasing face-to-face social interactions and outdoor activities. Future research should explore strategies to help online interventions and education to be more successful with individuals with FXS, given this may become a resource for families not geographically able to access in-person resources.

FMR1 premutation cytosine-guanine-guanine repeat expansion alleles are relatively common mutations in the general population that are associated with a neurodegenerative disease (fragile X-associated tremor/ataxia syndrome), reproductive health problems and potentially a wide range of additional mental and general health conditions that are not yet well-characterised. The International Fragile X Premutation Registry (IFXPR) was developed to facilitate and encourage research to better understand the FMR1 premutation and its impact on human health, to facilitate clinical trial readiness by identifying and characterising diverse cohorts of individuals interested in study participation, and to build community and collaboration among carriers, family members, researchers and clinicians around the world. Here, we describe the development and content of the IFXPR, characterise its first 747 registrants from 32 countries and invite investigators to apply for recruitment support for their project(s). With larger numbers, increased diversity and potentially the future clinical characterisation of registrants, the IFXPR will contribute to a more comprehensive and accurate understanding of the fragile X premutation in human health and support treatment studies.

The objectives were to describe the demographic characteristics of children with Fragile X syndrome (FXS) and to determine predictors of attendance at Fragile X (FX) clinics. Findings from the Community Support Network (CSN) and Our Fragile X World (OFXW) samples showed that children who attended FX Clinics were mostly male, high-school aged or younger, and white, non-Hispanic. Using logistic regression models, awareness about FX Clinic services, guardian education, and income (CSN), and child age, family income, and total number of co-occurring conditions (OFXW) were predictors of clinic attendance. Demographic and child characteristics accounted for a large portion of the explained variance. Importantly, symptom severity and parent knowledge about services were independent predictors beyond the demographic characteristics of families.

Since its identification in 2001, awareness of fragile X-associated tremor/ataxia syndrome (FXTAS) has increased. The number of patients and families impacted by the condition continues to grow. Families with and without a history of fragile X syndrome (FXS) are impacted. Patients are usually identified based on their neurological findings such as intentional tremor, balance and gait difficulties, cognitive impairment, and brain MRI abnormalities.

These recommendations describe the minimum standard criteria for genetic counseling and testing of individuals and families with fragile X syndrome, as well as carriers and potential carriers of a fragile X mutation. The original guidelines (published in 2000) have been revised, replacing a stratified pre- and full mutation model of fragile X syndrome with one based on a continuum of gene effects across the full spectrum of FMR1 CGG trinucleotide repeat expansion. This document reviews the molecular genetics of fragile X syndrome, clinical phenotype (including the spectrum of premature ovarian failure and fragile X-associated tremor-ataxia syndrome), indications for genetic testing and interpretation of results, risks of transmission, family planning options, psychosocial issues, and references for professional and patient resources. These recommendations are the opinions of a multicenter working group of genetic counselors with expertise in fragile X syndrome genetic counseling, and they are based on clinical experience, review of pertinent English language articles, and reports of expert committees. These recommendations should not be construed as dictating an exclusive course of management, nor does use of such recommendations guarantee a particular outcome. The professional judgment of a health care provider, familiar with the facts and circumstances of a specific case, will always supersede these recommendations.

The National Society of Genetic Counselors' (NSGC) recommendations for fragile X syndrome (FXS) genetic counseling are intended to assist health care professionals who provide genetic counseling for individuals and families in whom the diagnosis of FXS is strongly suspected or has been made. The recommendations are the opinions of genetic counselors with expertise in FXS counseling and are based on clinical experience, a review of pertinent English language medical articles, and reports of expert committees. These recommendations should not be construed as dictating an exclusive course of management, nor does use of such recommendations guarantee a particular outcome. These recommendations do not displace a health care provider's professional judgment based on the clinical circumstances of a particular client.