The International Fragile X Premutation Registry: building a resource for research and clinical trial readiness.

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.

Cerebral Microbleeds in Fragile X-Associated Tremor/Ataxia Syndrome.

BACKGROUND: Fragile X-associated tremor/ataxia syndrome is a neurodegenerative disease of late onset developed by carriers of the premutation in the fragile x mental retardation 1 (FMR1) gene. Pathological features of neurodegeneration in fragile X-associated tremor/ataxia syndrome include toxic levels of FMR1 mRNA, ubiquitin-positive intranuclear inclusions, white matter disease, iron accumulation, and a proinflammatory state. OBJECTIVE: The objective of this study was to analyze the presence of cerebral microbleeds in the brains of patients with fragile X-associated tremor/ataxia syndrome and investigate plausible causes for cerebral microbleeds in fragile X-associated tremor/ataxia syndrome. METHODS: We collected cerebral and cerebellar tissue from 15 fragile X-associated tremor/ataxia syndrome cases and 15 control cases carrying FMR1 normal alleles. We performed hematoxylin and eosin, Perls and Congo red stains, ubiquitin, and amyloid ß protein immunostaining. We quantified the number of cerebral microbleeds, amount of iron, presence of amyloid ß within the capillaries, and number of endothelial cells containing intranuclear inclusions. We evaluated the relationships between pathological findings using correlation analysis. RESULTS: We found intranuclear inclusions in the endothelial cells of capillaries and an increased number of cerebral microbleeds in the brains of those with fragile X-associated tremor/ataxia syndrome, both of which are indicators of cerebrovascular dysfunction. We also found a suggestive association between the amount of capillaries that contain amyloid ß in the cerebral cortex and the rate of disease progression. CONCLUSION: We propose microangiopathy as a pathologic feature of fragile X-associated tremor/ataxia syndrome. © 2021 International Parkinson and Movement Disorder Society.

Inequities in diagnosis of Fragile X syndrome in Colombia.

BACKGROUND: Fragile X syndrome (FXS) is the most common cause of inherited intellectual disability and autism spectrum disorder (ASD). In Colombia, there are no screening or testing protocols established for the diagnosis of FXS. In this study, we aimed to describe the diagnostic trends of FXS in Colombia. METHODS: Data were included on 1322 individuals obtained based on data from the only 2 databases available. Sociodemographic information and data related to the diagnostic process were obtained and included in this study. RESULTS: The average age at the time of diagnosis for individuals with the full mutation (FM) was of 26.9 ± 2.57 years and was strongly dependent on sex and socioeconomic status. Most individuals with a molecular diagnosis were from the main cities. CONCLUSION: The overall age of diagnosis of FXS is later in life than reports from other countries. Restricted access to molecular testing through the national health system might explain this discrepancy in Colombia.

Fragile X-Associated Tremor/Ataxia Syndrome (FXTAS): Pathophysiology and Clinical Implications.

The fragile X-associated tremor/ataxia syndrome (FXTAS) is a neurodegenerative disorder seen in older premutation (55-200 CGG repeats) carriers of FMR1. The premutation has excessive levels of FMR1 mRNA that lead to toxicity and mitochondrial dysfunction. The clinical features usually begin in the 60 s with an action or intention tremor followed by cerebellar ataxia, although 20% have only ataxia. MRI features include brain atrophy and white matter disease, especially in the middle cerebellar peduncles, periventricular areas, and splenium of the corpus callosum. Neurocognitive problems include memory and executive function deficits, although 50% of males can develop dementia. Females can be less affected by FXTAS because of a second X chromosome that does not carry the premutation. Approximately 40% of males and 16% of female carriers develop FXTAS. Since the premutation can occur in less than 1 in 200 women and 1 in 400 men, the FXTAS diagnosis should be considered in patients that present with tremor, ataxia, parkinsonian symptoms, neuropathy, and psychiatric problems. If a family history of a fragile X mutation is known, then FMR1 DNA testing is essential in patients with these symptoms.

Nausea and Vomiting as Initial Manifestations of Pediatric NMOSD.

Intractable nausea and vomiting are commonly attributed to gastrointestinal (GI) conditions but can sometimes be a symptom of an underlying central nervous system disease. One potentially overlooked neurologic cause of intractable nausea and vomiting that is refractory to antiemetics is area postrema syndrome (APS). APS is a condition characterized by lesions of the dorsal caudal medulla and is considered a core clinical feature of neuromyelitis optica spectrum disorder (NMOSD). APS is present in up to 30% of patients ultimately diagnosed with NMOSD and can be the first presenting symptom of NMOSD in 12% of patients, as our case illustrates. Importantly, APS is highly responsive to immunotherapy. We present the case of a 14-year-old female with a history of migraines who presented to the emergency department multiple times for persistent nausea, vomiting, and hiccups. Multiple GI diagnoses were considered until she developed additional neurologic symptoms that prompted further workup and revealed the final diagnosis of NMOSD-APS. We posit that NMOSD-APS should be considered in the differential diagnosis for patients with intractable nausea and vomiting, especially in patients with a negative GI workup result and poor response to antiemetics.

Severe Vaginal Myiasis: Successful Management With Ivermectin.

Myiasis refers to infestation of living animals or humans by maggots or fly larvae. Urogenital myiasis is a rare condition that is linked to poor sanitary conditions and limited access to healthcare and with few published case reports. Here, we describe the case of a 67-year-old homeless woman with multiple comorbidities, who presented with extensive vaginal myiasis requiring inpatient management with ivermectin, ceftriaxone, and metronidazole and daily larvae extraction and debridement. The relevance of this case is providing a report of a successful management with ivermectin of a case of severe vaginal myiasis. Severe cases of vaginal myiasis can require repeated debridement of necrotic tissue and systemic antibiotics in addition to antiparasitic medication. People living under poor sanitary conditions and with poor hygienic practices are at increased risk for severe vaginal myiasis.

Overlapping Molecular Pathways Leading to Autism Spectrum Disorders, Fragile X Syndrome, and Targeted Treatments.

Autism spectrum disorders (ASD) are subdivided into idiopathic (unknown) etiology and secondary, based on known etiology. There are hundreds of causes of ASD and most of them are genetic in origin or related to the interplay of genetic etiology and environmental toxicology. Approximately 30 to 50% of the etiologies can be identified when using a combination of available genetic testing. Many of these gene mutations are either core components of the Wnt signaling pathway or their modulators. The full mutation of the fragile X mental retardation 1 (FMR1) gene leads to fragile X syndrome (FXS), the most common cause of monogenic origin of ASD, accounting for ~ 2% of the cases. There is an overlap of molecular mechanisms in those with idiopathic ASD and those with FXS, an interaction between various signaling pathways is suggested during the development of the autistic brain. This review summarizes the cross talk between neurobiological pathways found in ASD and FXS. These signaling pathways are currently under evaluation to target specific treatments in search of the reversal of the molecular abnormalities found in both idiopathic ASD and FXS.

Fragile X associated neuropsychiatric disorders in a male without FXTAS.

Fragile X syndrome (FXS) is the most common inherited cause of intellectual disability and autism spectrum disorder. In most cases, it is due to an expansion of the CGG triplet to more than 200 repeats within the promoter region of the FMR1 gene. In the premutation (PM) the trinucleotide is expanded to 55-200 repeats. PM carriers can present with disorders associated with the PM including fragile X-associated tremor/ataxia syndrome (FXTAS) and fragile X-associated ovarian insufficiency (FXPOI). Recently fragile X-associated neuropsychiatric disorders (FXAND) was proposed as an umbrella term to include the neuropsychiatric disorders that are more prevalent in PM carriers compared to the general population such as anxiety, depression, chronic fatigue, alcohol abuse, and psychosis, among others. The patient in our study was evaluated by a team of clinicians from the University del Valle in Cali who traveled to Ricaurte, a Colombian town known for being a genetic geographic cluster of FXS. A detailed medical history was collected and complete physical, neurological and psychiatric evaluations were performed in addition to molecular and neuroradiological studies. We report the case of a 78-year-old man, PM carrier, without FXTAS whose main clinical presentation consists of behavioral changes and psychosis. Brain imaging revealed white matter lesions in the periventricular region and mild cerebral atrophy. Although anxiety and depression are the most common neuropsychiatric manifestations in PM carriers, it is important to perform a complete psychiatric evaluation since some patients may present with behavioral changes and psychosis.

Elevated FMR1-mRNA and lowered FMRP - A double-hit mechanism for psychiatric features in men with FMR1 premutations.

Fragile X syndrome (FXS) is caused by a full mutation of the FMR1 gene (>200 CGG repeats and subsequent methylation), such that there is little or no FMR1 protein (FMRP) produced, leading to intellectual disability (ID). Individuals with the premutation allele (55-200 CGG repeats, generally unmethylated) have elevated FMR1 mRNA levels, a consequence of enhanced transcription, resulting in neuronal toxicity and a spectrum of premutation-associated disorders, including the neurodegenerative disorder fragile X-associated tremor/ataxia syndrome (FXTAS). Here we described 14 patients who had both lowered FMRP and elevated FMR1 mRNA levels, representing dual mechanisms of clinical involvement, which may combine features of both FXS and FXTAS. In addition, the majority of these cases show psychiatric symptoms, including bipolar disorder, and/or psychotic features, which are rarely seen in those with just FXS.

Ataxia as the Major Manifestation of Fragile X-Associated Tremor/Ataxia Syndrome (FXTAS): Case Series.

Fragile X-associated tremor and ataxia syndrome (FXTAS) is a neurodegenerative disease developed by carriers of a premutation in the fragile X mental retardation 1 (FMR1) gene. The core clinical symptoms usually manifest in the early 60s, typically beginning with intention tremor followed by cerebellar ataxia. Ataxia can be the only symptom in approximately 20% of the patients. FXTAS has a slow progression, and patients usually experience advanced deterioration 15 to 25 years after the initial diagnosis. Common findings in brain imaging include substantial brain atrophy and white matter disease (WMD). We report three cases with an atypical clinical presentation, all presenting with gait problems as their initial manifestation and with ataxia as the dominant symptom without significant tremor, as well as a faster than usual clinical progression. Magnetic resonance imaging (MRI) was remarkable for severe brain atrophy, ventriculomegaly, thinning of the corpus callosum, and periventricular WMD. Two cases were diagnosed with definite FXTAS on the basis of clinical and radiological findings, with one individual also developing moderate dementia. Factors such as environmental exposure and general anesthesia could have contributed to their clinical deterioration. FXTAS should be considered in the differential diagnosis of patients presenting with ataxia, even in the absence of tremor, and FMR1 DNA testing should be sought in those with a family history of fragile X syndrome or premutation disorders.

Surgimiento de los micro-RNA como biomarcadores potenciales en diversas enfermedades / Emergence of micro-RNAs as potential biomarkers in different diseases / Surgimento dos micro-RNA como bio-marcadores potenciais em diversas doenças

El objetivo de esta revisión es evidenciar el potencial de los micro-RNA (mi-RNA) como biomarcadores en diferentes enfermedades. Los mi-RNA son ácidos nucleicos de ≈ 22 nucleótidos que regulan la traducción de RNA mensajeros (mRNA) codificantes y producen una regulación postranscripcional de la expresión génica. La mayoría de ellos son altamente conservados y tienen una distribución tisular específica, de manera que juegan un papel importante como reguladores de la función celular y la fisiopatología de los diferentes órganos del cuerpo humano. Los mi-RNA surgen como candidatos para ser biomarcadores debido a que se han encontrado cambios en su expresión en diversas enfermedades (cáncer, daño hepático y cardiopatías), con alteración de sus niveles en plasma suero, orina y saliva. Sin embargo, aunque algunos presentan consistencia en su perfil de expresión, otros han sido reportados como posibles candidatos para más de una enfermedad, lo que limita su especificidad y su utilidad diagnóstica. Es pertinente hacer nuevos estudios que ahonden sobre su significado en procesos patológicos y sobre su papel como posibles biomarcadores.

The objective of this review is to evidence the potential of micro-RNAs (mi-RNAs) as possible diagnostic biomarkers in different diseases. Micro-RNAs are nucleic acids of 22 nucleotides that regulate the translation of coding messenger RNAs (mRNAs), and produce a post-transcriptional regulation of genetic expression. Most mi-RNAs are highly conserved and show a tissue-specific distribution; therefore, they play an important role in the regulation of cell function and the physiopathology of different organs. Micro-RNAs emerge as potential candidates for biomarkers due to the changes in their levels of expression in different situations (cancer, hepatic and cardiovascular diseases) and in fluids such as plasma, serum, urine and saliva. However, although some mi-RNAs have a consistent expression profile, others have been reported as possible biomarkers for more than one disease, thus limiting their specificity and usefulness as diagnostic tools. Further studies are important to define the significance of mi-RNAs in pathologic processes and their role as possible biomarkers.

O objetivo desta revisão é evidenciar o potencial dos micro-RNA (mi-RNA) como bio-marcadores em diferentes doenças. Os mi-RNA são ácidos nucleicos de ≈ 22 nucleótidos que regulam a tradução de RNA mensageiros (mRNA) codificantes e produzem uma regulação pós-transcripcional da expressão génica. A maioria desses são altamente conservados e tem uma distribuição tissular específica, de maneira que jogam um papel importante como reguladores da função celular e a fisiopatologia dos diferentes órgãos do corpo humano. Os mi-RNA surgem como candidatos para ser bio-marcadores devido a que se hão encontrado câmbios em sua expressão em diversas doenças (câncer, dano hepático e cardiopatias), com alteração de seus níveis em plasma, soro, urina e saliva. Embora, ainda alguns apresentam consistência em seu perfil de expressão, outros hão sido reportados como possíveis candidatos para mais de uma doença, o que limita sua especificidade e sua utilidade diagnóstica. É pertinente fazer novos estudos que abondem sobre seu significado em processos patológicos e sobre seu papel como possível bio-marcadores.