Fragile X Research Articles

Fragile X mental retardation protein modulates translation of proteins with predicted tendencies for liquid-liquid phase separation.

The Fragile X Mental Retardation Protein (FMRP) is an RNA-binding protein and a key regulator of translation in neurons, hence crucial for neural development and plasticity. FMRP loss, resulting from mutations in the Fmr1 gene, leads to Fragile X Syndrome (FXS) and Autism Spectrum Disorder (ASD), the most common inherited intellectual disabilities. Ribosome profiling in neurons consistently reveals that FMRP-knockout (FK) significantly down-regulates the translation of numerous lengthy genes, many of which are FMRP-binding targets and associated with ASD. Despite these findings, the functional explanation for FMRP's translation regulation of large neuronal proteins remains elusive. Our present study compiles data from published ribosome profiling studies, to identify genes with significantly decreased translation in FK neurons. Using bioinformatic analysis and machine-learning sequence-based tools, PSPredictor and FuzDrop, we found that the proteins encoded by these genes are predicted to be enriched in intrinsically disordered regions and are prone to liquid-liquid phase separation. These findings suggest that FMRP modulates the translation of proteins involved in the formation of biomolecular condensates. Our results can have significant implications for understanding the molecular mechanisms of FXS and ASD, adding complexity to FMRP's regulatory functions, thus offering avenues for further exploration and targeted therapeutic interventions in intellectual disability disorders.

An iPSC model of fragile X syndrome reflects clinical phenotypes and reveals m 6 A- mediated epi-transcriptomic dysregulation underlying synaptic dysfunction.

Fragile X syndrome (FXS), the leading genetic cause of intellectual disability, arises from FMR1 gene silencing and loss of the FMRP protein. N6-methyladenosine (m 6 A) is a prevalent mRNA modification essential for post-transcriptional regulation. FMRP is known to bind to and regulate the stability of m 6 A-containing transcripts. However, how loss of FMRP impacts on transcriptome-wide m 6 A modifications in FXS patients remains unknown. To answer this question, we generated cortical neurons differentiated from induced pluripotent stem cells (iPSC) derived from healthy subjects and FXS patients. In electrophysiology recordings, we validated that synaptic and neuronal network defects in iPSC-derived FXS neurons corresponded to the clinical EEG data of the patients from which the corresponding iPSC line was derived. In analysis of transcriptome-wide methylation, we show that FMRP deficiency led to increased translation of m 6 A writers, resulting in hypermethylation that primarily affecting synapse-associated transcripts and increased mRNA decay. Conversely, in the presence of an m 6 A writer inhibitor, synaptic defects in FXS neurons were rescued. Taken together, our findings uncover that an FMRP-dependent epi-transcriptomic mechanism contributes to FXS pathogenesis by disrupting m 6 A modifications in FXS, suggesting a promising avenue for m 6 A- targeted therapies.

Systematic Review: Fragile X Syndrome Across the Lifespan with a Focus on Genetics, Neurodevelopmental, Behavioral and Psychiatric Associations

Background/Objectives: Fragile X syndrome (FXS) is one of the most common genetic causes of intellectual developmental disability and autism spectrum disorder (ASD), second only to Down’s syndrome and associated with a broad range of neurodevelopmental, behavioral, and psychiatric challenges. FXS may be present in infants or young children with characteristic dysmorphic features, developmental delays, and behavioral challenges. The diagnosis of FXS is confirmed by the molecular genetic testing of the FMR1 gene encoding fragile X messenger RNA-binding protein (FMRP), involved in regulating the translation of multiple mRNAs which play a key role in neuronal development and synaptic plasticity. Understanding the genetic cause, pathophysiology, and natural history of FXS is crucial for identifying commonly associated comorbidities, instituting effective therapeutic interventions, and improving long-term outcomes. Methods: This systematic review employed a comprehensive literature search using multiple electronic databases including PubMed, Web of Science, and Scopus with keywords related to fragile X syndrome, lifespan, genetics, neurodevelopmental, behavioral, and psychiatric disorders. Results: FXS is associated with an increased risk for specific neurodevelopmental, or psychiatric disorders. Symptoms and challenges associated with FXS vary based on multiple factors, including genetic differences, age, sex, comorbid conditions, various environmental influences, the availability of support, and opportunities for therapeutic interventions. Knowledge of these associations helps guide caregivers and clinicians in identifying potentially treatable conditions that can help to improve the lives of affected patients and their families. Conclusions: The focus of this article is to explore and describe the genetic underpinnings of FXS, identify associated developmental, behavioral, and psychiatric conditions over the lifespan, and provide a review of clinical features, therapeutic interventions including investigational treatments, and current research updates.

Altered olfactory responses in Fmr1 KO mice

Fragile X syndrome (FXS) is a neurodevelopmental disorder oftentimes associated with abnormal social behaviors and altered sensory responsiveness. It is hypothesized that the inappropriate filtering of sensory stimuli, including olfaction, can lead to aberrant social behavior in FXS. However, previous studies investigating olfaction in animal models of FXS have shown inconsistent results. Here, we found that Fmr1 knock-out (KO) mice, a mouse model of FXS, showed increased sniffing duration for non-social odors during their first exposure. Additionally, while wild-type (WT) males demonstrated differences in behavioral patterns between non-social odors while Fmr1 KO males did not show such distinction. We also showed that Fmr1 KO males spent significantly less time sniffing female urine odor compared to WT males. Moreover, we found an increased volume of the olfactory bulb in Fmr1 KO males. Overall, our findings suggest that the Fmr1 KO mice demonstrate atypical olfactory behaviors as well as structural changes in the olfactory bulb.

GABAergic Progenitor Cell Graft Rescues Cognitive Deficits in Fragile X Syndrome Mice.

Fragile X syndrome (FXS) is an inherited neurodevelopmental disorder characterized by a range of clinical manifestations with no effective treatment strategy to date. Here, transplantation of GABAergic precursor cells from the medial ganglionic eminence (MGE) is demonstrated to significantly improve cognitive performance in Fmr1 knockout (KO) mice. Within the hippocampus of Fmr1-KO mice, MGE-derived cells from wild-type donor mice survive, migrate, differentiate into functionally mature interneurons, and form inhibitory synaptic connections with host pyramidal neurons. MGE cell transplantation restores Ras-PKB signaling in pyramidal neurons, enhances AMPA receptor trafficking, rescues synaptic plasticity, and corrects abnormal hippocampal neural oscillations. These findings highlight the potential of GABAergic precursor cell transplantation as a promising therapeutic strategy for FXS.

Enhanced CB1 receptor function in GABAergic neurons mediates hyperexcitability and impaired sensory-driven synchrony of cortical circuits in Fragile X Syndrome model mice.

Electroencephalographic (EEG) recordings in individuals with Fragile X Syndrome (FXS) and the mouse model of FXS ( Fmr1 KO) display cortical hyperexcitability at rest, as well as deficits in sensory-driven cortical network synchrony. A form of circuit hyperexcitability is observed in ex vivo cortical slices of Fmr1 KO mice as prolonged persistent activity, or Up, states. It is unknown if the circuit mechanisms that cause prolonged Up states contribute to FXS-relevant EEG phenotypes. Here we examined the role of endocannabinoids (eCB) in prolonged Up states in slices and resting and sensory-driven EEG phenotypes in awake Fmr1 KO mice. Bidirectional changes in eCB function are reported in the Fmr1 KO that depend on synapse type (excitatory or inhibitory). We demonstrate that pharmacological or genetic reduction of Cannabinoid Receptor 1 (CB1R) in GABAergic neurons rescues prolonged cortical Up states and deficits in sensory-driven cortical synchrony in Fmr1 KO mice. In support of these findings, recordings from Fmr1 KO cortical Layer (L) 2/3 pyramidal neurons revealed enhanced CB1R-mediated suppression of inhibitory synaptic currents. In contrast, genetic reduction of Cnr1 in glutamatergic neurons did not affect Up state duration, but deletion of Fmr1 in the same neurons was sufficient to cause long Up states. These findings support a model where loss of Fmr1 in glutamatergic neurons leads to enhanced CB1R-mediated suppression of GABAergic synaptic transmission, prolonged cortical circuit activation and reduced sensory-driven circuit synchronization. Results suggest that antagonism of CB1Rs as a therapeutic strategy to correct sensory processing deficits in FXS.

Role of peroxisome proliferator-activated receptors α and γ in mediating the beneficial effects of β-caryophyllene in a rat model of fragile X syndrome.

β-Caryophyllene (BCP) is a naturally occurring sesquiterpene found in numerous plant species, including Cannabis sativa. BCP has shown a high safety profile and a wide range of biological functions, including beneficial effects in neurodegenerative and inflammatory diseases. Here, we used behavioral, pharmacological, and in-silico docking analyses to investigate the effects and mechanism of action of BCP in Fragile X Syndrome (FXS), the most common inherited cause of Autism Spectrum Disorder (ASD) and intellectual disability. To this aim, we used the recently validated Fmr1-Δexon 8 rat model of FXS, that is also a genetic rat model of ASD. Acute and repeated oral administration of BCP rescued the cognitive deficits displayed by Fmr1-Δexon 8 rats, without inducing tolerance after repeated administration. These beneficial effects were mediated by activation of hippocampal peroxisome proliferator-activated receptors (PPARs) α and γ, and were mimicked by the PPARα agonist Fenofibrate and the PPARγ agonist Pioglitazone. Conversely, CB2 cannabinoid receptors were not involved. Docking analyses further confirmed the ability of BCP to bind rat PPARs. Together, our findings demonstrate that hippocampal PPARs α and γ play a role in the cognitive deficits observed in a rat model of FXS, and provide first preclinical evidence about the efficacy and mechanism of action of BCP in neurodevelopmental disorders.

Different faces of autism: Patients with mutations in PTEN and FMR1 genes.

Autism spectrum disorder (ASD) is among the most common neurodevelopmental conditions in humans. While public awareness of the challenges faced by individuals with autism is steadily increasing, the underlying causes of abnormalities observed in ASD remains incompletely understood. The autism spectrum is notably broad, with symptoms that can manifest in various forms and degrees of severity. Core features of ASD, such as communication difficulties, impaired social interactions, and restricted patterns of behavior, interests, and activities, are often accompanied by other co‑occurring conditions, such as anxiety. ASD affects individuals regardless of gender, race, or ethnicity. Although we are currently unable to pinpoint a single definitive cause of autism, it is clear that genetics play a crucial role in its development. The first genes associated with an increased risk for ASD were discovered in rare monogenic disorders, such as fragile X syndrome (FXS), caused by mutations in the fragile X messenger ribonucleoprotein 1 (FMR1) gene, and macrocephaly, linked to mutations in the phosphatase and tensin homolog (PTEN) gene. This review aims to summarize the current knowledge of ASD in patients with mutations in the FMR1 and PTEN genes.

Trinucleotide Repeat Expansion and RNA Dysregulation in Fragile X Syndrome: Emerging Therapeutic Approaches.

Fragile X Syndrome (FXS) is characterized by intellectual impairment caused by CGG repeat expansion in the FMR1 gene. When repeats exceed 200, they induce DNA methylation of the promoter and the repeat region, resulting in transcriptional silencing of the FMR1 gene and the subsequent loss of FMRP protein. In the past decade or so, research has focused on the role of FMRP as an RNA-binding protein involved in translation inhibition in the brain in FXS model mice, particularly by slowing or stalling ribosome translocation on mRNA. More recent advances have shown that FMRP has a profound role in RNA splicing, at least in some cases by modulating the translation of splicing factor mRNAs. In a surprise, the human FMR1 gene is transcribed in most cases even with a full CGG expansion. However, much of the FMR1 that is produced is mis-spliced, which can be corrected by splice-switching antisense oligonucleotide (ASO) administration. Other recent findings suggest that inhibition of multiple kinases can demethylate the FMR1 gene and induce the formation of an R-loop in the CGG repeat region, leading to contraction of the repeat and FMRP restoration. These insights are paving the way for possible future therapeutic approaches for this disorder. We highlight the importance of FMRP restoration by ASO-mediated splice switching or CGG repeat modulation as key advances that may lead to successful treatments for FXS.

Therapeutic approaches for repeat expansion diseases: a comprehensive review

Repeat expansion diseases (REDs) are genetic disorders caused by unusual expansions of DNA sequences within certain genes. They cause several neurodegenerative diseases including Huntington’s disease (HD), myotonic dystrophy (DM), spinal and bulbar muscular atrophy (SBMA), fragile X syndrome (FXS), and others. The pathogenic repeat expansions disrupt normal cellular processes by producing aberrant RNA repeat sequences, leading to toxic protein aggregation, RNA foci, and altered gene expression. Although they belong to the rare disease group, such diseases must be investigated to understand integral mechanisms and prevention. Current methods for alleviating these diseases involve—gene silencing therapies by antisense oligonucleotides (ASOs) and RNA interference (RNAi), CRISPR/Cas9 gene editing, small molecule therapies, etc. ASOs and RNAi reduce toxic protein production genes while CRISPR/Cas9 excise or alter expanded repeats. Small molecule therapies targeting RNA repeat-binding or proteostasis regulation are being developed to alleviate toxic protein accumulation, prevent RNA toxic foci formation, and promote the degradation of misfolded proteins. Additionally, gene replacement and regulatory element modification restore normal gene function. Some researchers tried to modulate toxic protein aggregation using heat shock proteins and chemical chaperones. This is a comprehensive review on the available research on RED treatment and their ongoing challenges, such as efficient delivery of therapies to the central nervous system, minimizing off-target effects in gene editing, sustaining therapeutic efficacy, and addressing toxicity and scalability in large-scale applications.

Discovery of MDI-114215: A Potent and Selective LIMK Inhibitor To Treat Fragile X Syndrome.

LIMKs are serine/threonine and tyrosine kinases responsible for controlling cytoskeletal dynamics as key regulators of actin stability, ensuring synaptic health through normal synaptic bouton structure and function. However, LIMK1 overactivation results in abnormal dendritic synaptic development that characterizes the pathogenesis of Fragile X Syndrome (FXS). As a result, the development of LIMK inhibitors represents an emerging disease-modifying therapeutic approach for FXS. We report the discovery of MDI-114215 (85), a novel, potent allosteric dual-LIMK1/2 inhibitor that demonstrates exquisite kinome selectivity. 85 reduces phospho-cofilin in mouse brain slices and rescues impaired hippocampal long-term potentiation in brain slices from FXS mice. We also show that LIMK inhibitors are effective in reducing phospho-cofilin levels in iPSC neurons derived from FXS patients, demonstrating 85 to be a potential therapeutic candidate for FXS that could have broad application to neurological disorders or cancers caused by LIMK1/2 overactivation and actin instability.

Somatic Instability Leading to Mosaicism in Fragile X Syndrome and Associated Disorders: Complex Mechanisms, Diagnostics, and Clinical Relevance

Fragile X syndrome (FXS) is a genetic condition caused by the inheritance of alleles with >200 CGG repeats in the 5′ UTR of the fragile X messenger ribonucleoprotein 1 (FMR1) gene. These full mutation (FM) alleles are associated with DNA methylation and gene silencing, which result in intellectual disabilities, developmental delays, and social and behavioral issues. Mosaicism for both the size of the CGG repeat tract and the extent of its methylation is commonly observed in individuals with the FM. Mosaicism has also been reported in carriers of premutation (PM) alleles, which have 55–200 CGG repeats. PM alleles confer risk for the fragile X premutation-associated conditions (FXPAC), including FXTAS, FXPOI, and FXAND, conditions thought to be due to the toxic consequences of transcripts containing large CGG-tracts. Unmethylated FM (UFM) alleles are transcriptionally and translationally active. Thus, they produce transcripts with toxic effects. These transcripts do produce some FMRP, the encoded product of the FMR1 gene, albeit with reduced translational efficiency. As a result, mosaicism can result in a complex clinical presentation. Here, we review the concept of mosaicism in both FXS and in PM carriers, including its potential clinical significance.

Pre-trained artificial intelligence language model represents pragmatic language variability central to autism and genetically related phenotypes.

Autism is clinically defined by challenges with social language, including difficulties offering on-topic language in a conversation. Similar differences are also seen in genetically related conditions such as fragile X syndrome (FXS), and even among those carrying autism-related genes who do not have clinical diagnoses (e.g., the first-degree relatives of autistic individuals and carriers of the FMR1 premutation), which suggests there are genetic influences on social language related to the genes involved in autism. Characterization of social language is therefore important for informing potential intervention strategies and understanding the causes of communication challenges in autism. However, current tools for characterizing social language in both clinical and research settings are very time and labor intensive. In this study, we test an automized computational method that may address this problem. We used a type of artificial intelligence known as pre-trained language model to measure aspects of social language in autistic individuals and their parents, non-autistic comparison groups, and individuals with FXS and the FMR1 premutation. Findings suggest that these artificial intelligence approaches were able to identify differences in social language in autism, and to provide insight into the individuals' ability to keep a conversation on-topic. These findings also were associated with broader measures of participants' social communication ability. This study is one of the first to use artificial intelligence models to capture important differences in social language in autism and genetically related groups, demonstrating how artificial intelligence might be used to provide automatized, efficient, and objective tools for language characterization.

Specialization of the brain for language in children with Fragile X Syndrome: a functional Near Infrared Spectroscopy study

Specialization of the brain for language is early emerging and essential for language learning in young children. Fragile X Syndrome (FXS) is a neurogenetic disorder marked by high rates of delays in both expressive and receptive language, but neural activation patterns during speech and language processing are unknown. We report results of a functional Near Infrared Spectroscopy (fNIRS) study of responses to speech and nonspeech sounds in the auditory cortex in a sample of 2- to 10-year-old children with FXS and typically developing controls (FXS n = 23, TDC n = 15, mean age = 6.44 and 7.07 years, respectively). Specifically, we measured changes in oxygenated and deoxygenated hemoglobin in the auditory cortex during blocks of speech and nonspeech matched noise in children with FXS and sex-and-age-matched controls. Similar to controls, children with FXS showed hemodynamic change consistent with neural activation of the primary auditory regions for speech as well as leftward lateralization for speech sound processing, strength of which was associated with higher verbal abilities in FXS. However, while controls showed neural differentiation of speech and nonspeech in the left auditory cortex, children with FXS did not demonstrate differentiation of the two conditions in this study. In addition, the children with FXS showed a greater neural activation to the nonspeech condition overall. Overall, these results suggest that basic patterns of neural activation for speech are present in FXS in childhood, but neural response to nonspeech sounds may differ in FXS when compared to controls.

Apocynin, a Selective NADPH Oxidase (Nox2) Inhibitor, Ameliorates Behavioural and Learning Deficits in the Fragile X Syndrome Mouse Model.

Background/Objectives: Fragile X Syndrome (FXS) is associated with intellectual disability, hyperactivity, social anxiety and signs of autism. Hyperactivation of NADPH oxidase has been previously described in the brain of the male Fmr1-KO mouse. This work aims to demonstrate the efficacy of Apocynin, a specific NADPH oxidase inhibitor, in treating Fragile X mouse hallmarks. Methods: Free radicals, lipid and protein oxidation markers and behavioural and learning paradigms were measured after chronic treatment with orally administered vehicle, 10 mg/kg/day or 30 mg/kg/day of Apocynin. Results: The results revealed a reduction in testis weight, an increase in peritoneal fat, and no variation in body weight after chronic treatment. Furthermore, a reduction in hyperactivity was detected in Apocynin-treated male Fmr1-KO mice. Additionally, the higher dose of 30 mg/kg/day also improves behaviour and learning in the male Fmr1-KO mice, normalising free radical production and oxidative parameters. Moreover, a reduction in phospho-EKR1 and P47-Phox protein signals was observed in specific brain areas. Conclusions: Thus, chronic treatment with Apocynin could lead to a new therapeutic option for the Fragile X Syndrome.

FMR1 Disorders: Basics of Biology and Therapeutics in Development.

Fragile X Syndrome (FXS) presents with a constellation of phenotypes, including trouble regulating emotion and aggressive behaviors, disordered sleep, intellectual impairments, and atypical physical development. Genetic study of the X chromosome revealed that substantial repeat expansion of the 5' end of the gene fragile X messenger ribonucleoprotein 1 (FMR1) promoted DNA methylation and, consequently, silenced expression of FMR1. Further analysis proved that shorter repeat expansions in FMR1 also manifested in disease at later stages in life. Treatment and therapy options do exist, but they only manage symptoms. Up to now, no cure for FMR1 disorders exists. In this review, we aim to provide an overview of FMR1 biology and the latest research focused on developing therapeutic interventions that can potentially prevent and/or reverse FXS.

Syntactic Growth of Adolescent Boys With Fragile X Syndrome or Down Syndrome: A Longitudinal Study.

The current study addresses a gap in the literature regarding syntactic development of adolescent boys with fragile X syndrome (FXS) and Down syndrome (DS). Specifically, we ask whether syntactic skills plateau or continue to change during adolescence for these groups and whether the profile of syntactic change differs between boys with FXS and those with DS. Participants were 38 boys with FXS (with and without autism) and 20 boys with DS between the ages of 10 and 16 years, as well as 33 boys who were neurotypical between the ages of 3 and 8 years at study entry. Trained examiners evaluated the participants annually for four consecutive years. The evaluation included standardized language assessments and a conversational language sample, which was analyzed using mean length of utterance-morphemes and the Index of Productive Syntax. For each measure, we fit a series of candidate models, including the intercept-only model and models with nonverbal cognition and maternal IQ as moderators. We then used Akaike's information criteria-corrected to determine which model in a candidate set had the most empirical evidence. Our between-groups results indicated that FXS and DS have distinct syntactic profiles. However, our growth analyses and moderator analyses yielded mixed results. For most measures, the most likely models suggest that there is no plateau in the growth of syntactic skills for boys with FXS or DS and that nonverbal cognition is associated with the rate of change. These results suggest that syntactic change continues to occur throughout adolescence for boys with FXS or DS. The results also indicate that the growth profiles are distinct between the two groups. Future research with more participants from more diverse backgrounds would add more clarity to these findings. https://doi.org/10.23641/asha.27984548.

Challenges in diagnosis of fragile X-associated tremor/ataxia syndrome

Fragile X-associated tremor/ataxia syndrome (FXTAS) is a neurodegenerative disease recently described in the literature with a low percentage of detectability in patients due to insufficient awareness of doctors. The clinical picture is characterized by high phenotypic variability and coincidence of symptoms with other, more well-known motor disorders, in connection with which patients are observed for a long time with erroneous diagnoses. The issue of the differential diagnosis fragile X-associated tremor/ataxia syndrome with essential tremor, Parkinson’s disease, multiple system atrophy, spinocerebellar ataxia and progressive supranuclear paralysis is highlighted separately. In order to demonstrate the complexity of the diagnosis of this disease, a description of a case of genetically confirmed case of genetically confirmed fragile X-associated tremor/ataxia syndrome is presented. The described clinical case is represented by a combination of asymmetric disabling postural kinetic tremor of the hands, minor resting tremor, moderate cerebellar ataxia, asymmetric moderate dopa-responsive parkinsonism syndrome, mild cognitive impairment and psychotic symptoms. Not only the clinical picture of the disease is described in detail, but also the hereditary history of the patient: the results of a genetic study of a daughter premutation carriers of the FMR1 gene and a grandson suffering from Martin–Bell syndrome. A special feature of the clinical case is the long-term erroneous observation of a patient diagnosed with Parkinson’s disease, as well as high-dose therapy with levodopa/carbidopa 250 mg + 25 mg (up to 6 tablets per day). When studying the available domestic literature, the previously described cases of fragile X-associated tremor/ataxia syndrome were not found.

Women's healthcare providers' knowledge and practices surrounding fragile-X associated primary ovarian insufficiency (FXPOI).

This study investigates the knowledge gaps about fragile X-associated primary ovarian insufficiency (FXPOI) among women's healthcare providers. Previous research highlighted a lack of awareness regarding FXPOI as a cause of primary ovarian insufficiency (POI) and its diagnosis. The objective of this study was to describe these gaps and explore demographic factors influencing FXPOI knowledge in women's healthcare practitioners. A survey assessed familiarity with primary ovarian insufficiency and FXPOI knowledge among 107 women's healthcare providers and 14 medical students in the USA. Knowledge Scores, ranging from 0 to 16, were assigned, and demographic data, including healthcare provider type, specialty, and genetics exposure in education or training, were collected. Participants scored an average of 6.92 (± 2.19) out of 16 (42%) despite 88% of participants reporting genetics exposure in training. Maternal fetal medicine (MFM) and reproductive endocrinology (REI) providers significantly outperformed general obstetrics and gynecology (OBGYN) practitioners (p = 0.0186 and 0.0125, respectively). Participants with a genetic counselor in their clinic scored 8% higher (p = 0.0083) than those without. Additionally, medical school graduation year was a significant predictor for knowledge score (p = 0.0397). This study underscores limited FXPOI knowledge among women's healthcare providers, aligning with patient reports. Notably, medical specialty and the presence of a genetic counselor impacted knowledge, emphasizing the urgency for broader education in women's healthcare, particularly among OBGYNs, the initial point of contact for patients with POI symptoms.

Drug Treatments for Neurodevelopmental Disorders: Targeting Signaling Pathways and Homeostasis.

Preclinical and clinical evidence support the notion that neurodevelopmental disorders (NDDs) are synaptic disorders, characterized by excitatory-inhibitory imbalance. Despite this, NDD drug development programs targeting glutamate or gamma-aminobutyric acid (GABA) receptors have been largely unsuccessful. Nonetheless, recent drug trials in Rett syndrome (RTT), fragile X syndrome (FXS), and other NDDs targeting other mechanisms have met their endpoints. The purpose of this review is to identify the basis of these successful studies. Despite increasing evidence of disruption in synaptic homeostasis, most genetic variants associated with NDDs implicate proteins involved in cell regulation and not in neurotransmission. Metabolic processes, in particular mitochondrial function, appear to play a role in NDD pathophysiology. NDDs are also characterized by distinctive cell signaling abnormalities, which link cellular and synaptic homeostasis. Recent successful trials in NDDs, including those of trofinetide, the first drug specifically approved for one of these disorders (i.e., RTT), implicate the targeting of downstream processes (i.e., signaling pathways) rather than neurotransmitter receptors. Recent positive drug studies in NDDs and their underlying mechanisms, in conjunction with new knowledge on the pathophysiology of these disorders, support the concept that targeting signaling and cellular and synaptic homeostasis may be a preferred approach for ameliorating synaptic abnormalities in many NDDs.