Sertraline may improve language developmental trajectory in young children with fragile x syndrome: a retrospective chart review

An Update on Psychopharmacological Treatment of Autism Spectrum Disorder

While behavioral interventions remain the mainstay of treatment of autism spectrum disorder (ASD), several potential targeted treatments addressing the underlying neurophysiology of ASD have emerged in the last few years. These are promising for the potential to, in future, become part of the mainstay treatment in addressing the core symptoms of ASD. Although it is likely that the development of future targeted treatments will be influenced by the underlying heterogeneity in etiology, associated genetic mechanisms influencing ASD are likely to be the first targets of treatments and even gene therapy in the future for ASD. In this article, we provide a review of current psychopharmacological treatment in ASD including those used to address common comorbidities of the condition and upcoming new targeted approaches in autism management. Medications including metformin, arbaclofen, cannabidiol, oxytocin, bumetanide, lovastatin, trofinetide, and dietary supplements including sulforophane and N-acetylcysteine are discussed. Commonly used medications to address the comorbidities associated with ASD including atypical antipsychotics, serotoninergic agents, alpha-2 agonists, and stimulant medications are also reviewed. Targeted treatments in Fragile X syndrome (FXS), the most common genetic disorder leading to ASD, provide a model for new treatments that may be helpful for other forms of ASD. Appeared originally in Neurotherapeutics 2022; 19:248-262.

Longitudinal Adaptive Behavioral Outcomes in Ogden Syndrome by Seizure Status and Therapeutic Intervention

Ogden syndrome, also known as NAA10-related neurodevelopmental syndrome, is a rare genetic condition associated with pathogenic variants in the NAA10 N-terminal acetylation family of proteins. The condition was initially described in 2011, and is characterized by a range of neurologic symptoms, including intellectual disability and seizures, as well as developmental delays, psychiatric symptoms, congenital heart abnormalities, hypotonia and others. Previously published articles have described the etiology and phenotype of Ogden syndrome, mostly with retrospective analyses; herein, we report prospective data concerning its progress over time. Additionally, we describe the nature of seizures in this condition in greater detail, as well as investigate how already-available non-pharmaceutical therapies impact individuals with NAA10-related neurodevelopmental syndrome. Using Vineland-3 scores, we show decline in cognitive function over time in individuals with Ogden syndrome. Sub-domain analysis found the decline to be present across all modalities. Additional investigation between seizure and non-seizure groups showed no significant difference in adaptive behavior outcomes. Therapy investigation showed speech therapy to be the most commonly used therapy by individuals with NAA10-related neurodevelopmental syndrome, followed by occupational and physical therapy. with more severely affected individuals receiving more types of therapy than their less-severe counterparts. Early intervention analysis was only significantly effective for speech therapy, with analyses of all other therapies being non-significant. Our study portrays the decline in cognitive function over time of individuals within our cohort, independent of seizure status and therapies being received, and highlights the urgent need for the development of effective treatments for Ogden syndrome.

An Update on Psychopharmacological Treatment of Autism Spectrum Disorder

While behavioral interventions remain the mainstay of treatment of autism spectrum disorder (ASD), several potential targeted treatments addressing the underlying neurophysiology of ASD have emerged in the last few years. These are promising for the potential to, in future, become part of the mainstay treatment in addressing the core symptoms of ASD. Although it is likely that the development of future targeted treatments will be influenced by the underlying heterogeneity in etiology, associated genetic mechanisms influencing ASD are likely to be the first targets of treatments and even gene therapy in the future for ASD. In this article, we provide a review of current psychopharmacological treatment in ASD including those used to address common comorbidities of the condition and upcoming new targeted approaches in autism management. Medications including metformin, arbaclofen, cannabidiol, oxytocin, bumetanide, lovastatin, trofinetide, and dietary supplements including sulforophane and N-acetylcysteine are discussed. Commonly used medications to address the comorbidities associated with ASD including atypical antipsychotics, serotoninergic agents, alpha-2 agonists, and stimulant medications are also reviewed. Targeted treatments in Fragile X syndrome (FXS), the most common genetic disorder leading to ASD, provide a model for new treatments that may be helpful for other forms of ASD.

Review of Autism Profiles and Response to Sertraline in Fragile X Syndrome-Associated Autism vs. Non-syndromic Autism; Next Steps for Targeted Treatment

Given significant genetic, molecular, and phenotypic overlaps, researchers have begun to investigate whether targeted treatments for Fragile X Syndrome (FXS) could also be beneficial for patients with Autism Spectrum Disorder (ASD). For example, low-dose sertraline, an SSRI, was used in two recent controlled trials in children with FXS and ASD. The first trial recruited 52 children with FXS, 32 of which were also diagnosed with ASD; the second trial recruited 58 children with non-syndromic ASD. One focus of the present study is to compare the response to sertraline between the FXS-associated ASD and non-syndromic ASD groups. Another focus is to compare baseline ASD-related characteristics between the groups and review these differences within the context of recent literature comparing these populations. Our comparison showed more severe ASD profiles in children with non-syndromic ASD vs. FXS-associated ASD. Regarding response to sertraline, the FXS-ASD group displayed significant improvements in language development, while the non-syndromic group did not show any significant improvements. One possible explanation for this differential response is the distinct anxiety profiles that are seen in these two groups. The heightened anxiety phenotype seen in those with FXS-ASD may have led to a greater relief of anxiety symptoms with sertraline compared to those with non-syndromic ASD; this, in turn, could have led to measurably greater developmental gains. Further research is required to solidify this connection between anxiety relief and developmental gains in these populations.

Pharmacological Treatments for Fragile X Syndrome Based on Synaptic Dysfunction

BACKGROUND

Fragile X syndrome (FXS) is the most common form of monogenic hereditary cognitive impairment, including intellectual disability, autism, hyperactivity, and epilepsy.

METHODS

This article reviews the literature pertaining to the role of synaptic dysfunction in FXS.

RESULTS

In FXS, synaptic dysfunction alters the excitation-inhibition ratio, dysregulating molecular and cellular processes underlying cognition, learning, memory, and social behavior. Decades of research have yielded important hypotheses that could explain, at least in part, the development of these neurological disorders in FXS patients. However, the main goal of translating lab research in animal models to pharmacological treatments in the clinic has been so far largely unsuccessful, leaving FXS a still incurable disease.

CONCLUSION

In this concise review, we summarize and analyze the main hypotheses proposed to explain synaptic dysregulation in FXS, by reviewing the scientific evidence that led to pharmaceutical clinical trials and their outcome.

Treatment of Fragile X Syndrome with Cannabidiol: A Case Series Study and Brief Review of the Literature

Fragile X syndrome (FXS) is an X-linked dominant disorder caused by a mutation in the fragile X mental retardation 1 gene. Cannabidiol (CBD) is an exogenous phytocannabinoid with therapeutic potential for individuals with anxiety, poor sleep, and cognitive deficits, as well as populations with endocannabinoid deficiencies, such as those who suffer from FXS. The objective of this study was to provide a brief narrative review of recent literature on endocannabinoids and FXS and to present a case series describing three patients with FXS who were treated with oral CBD-enriched (CBD+) solutions. We review recent animal and human studies of endocannabinoids in FXS and present the cases of one child and two adults with FXS who were treated with various oral botanical CBD+ solutions delivering doses of 32.0 to 63.9 mg daily. Multiple experimental and clinical models of FXS combine to highlight the therapeutic potential of CBD for management of FXS. All three patients described in the case series exhibited functional benefit following the use of oral CBD+ solutions, including noticeable reductions in social avoidance and anxiety, as well as improvements in sleep, feeding, motor coordination, language skills, anxiety, and sensory processing. Two of the described patients exhibited a reemergence of a number of FXS symptoms following cessation of CBD+ treatment (e.g., anxiety), which then improved again after reintroduction of CBD+ treatment. Findings highlight the importance of exploring the therapeutic potential of CBD within the context of rigorous clinical trials.

New Therapeutic Options for Fragile X Syndrome

PURPOSE OF REVIEW

The purpose of this review is to provide an overview of current research and clinical practice guidelines in fragile X syndrome (FXS) with regard to therapeutic approaches in the management of this condition. The authors summarize and discuss findings from relevant preclinical studies and results from clinical trials in human subjects with FXS. Additionally, we provide an outline of the basic framework for understanding and providing educational and psychosocial supports for these individuals.

RECENT FINDINGS

Current treatments in FXS are largely symptom based and focused on managing associated psychiatric and behavioral co-morbidities. While data from animal studies has been promising in providing targeted treatments to correct the underlying deficits at the cellular level, there have not been as robust findings in human trials. There are several targeted treatments for FXS currently under development. Individuals with FXS present with several behavioral challenges including anxiety, social withdrawal, ADHD, hyperarousal, self-injury, and aggression. Therapeutic services are often necessary, such as behavioral intervention, speech and language therapy, occupational therapy, and individualized educational support; adjunctive psychopharmacologic treatment is often helpful as well. It is important to address these symptoms and weigh the evidence for the use of medications that target the underlying neurobiology and pathophysiology of the syndrome.

What's missing in autism spectrum disorder motor assessments?

BACKGROUND

Motor delays and impairments in autism spectrum disorders (ASD) are extremely common and often herald the emergence of pervasive atypical development. Clinical accounts of ASD and standardized measures of motor function have identified deficits in multiple motor domains. However, literature describing frequently used standardized motor assessments in children with ASD, their test properties, and their limitations are sparse.

METHODS

We systematically reviewed the literature to identify the most frequently used standardized motor assessments used to evaluate children with ASD from infancy to early childhood. All assessments included were required to possess reference norms, evaluate more than one motor domain, and have undergone some degree of validation.

RESULTS

We identified six frequently used standardized measures of motor function per our inclusion and exclusion criteria. We investigated and described in detail the psychometric properties of these assessments, their utility for use with children with ASD, and their individual and overall strengths and limitations. The global strengths of these assessments are the ability to identify early development delays and differences in fine and gross motor function in children with ASD. Global limitations of these studies are lack of validation in individuals with ASD and scoring systems that often miss specific and subtle abnormalities.

CONCLUSIONS

Standardized assessments of motor function have provided valuable information on motor impairments in ASD. However, significant limitations remain in the use of these measures in children with ASD. Moving forward, it is imperative that standardized measures of motor function receive greater validation testing in children with ASD to assess their potential application given the clinical heterogeneity of this condition. In addition, utilizing quantitative measures of motor function should allow for evaluation and comparison of individuals with ASD across the lifespan with varying cognitive and behavioral abilities.

Assessment of efficacy of prenatal genetic diagnosis for fragile X syndrome using nested PCR

Fragile X syndrome (FXS) is the most common inherited cause of intellectual disability and the leading monogenic cause of autism spectrum disorder. It has previously been demonstrated that prenatal genetic diagnosis is efficient for the diagnosis of FXS. The present study investigated the diagnostic effects of nested polymerase chain reaction (PCR) for fragile X mental retardation 1 (FMR1) and expanded CGG repeats. It was demonstrated that the nested PCR assay rapidly measured the multi-copies of the FMR1 gene in individual samples. The nested PCR assay detected normal CGG repeat lengths and expanded CGG repeat lengths with a low occurrence of false positives. In addition, the nested PCR assay resulted in increased sensitivity and specificity for patients with FXS. Furthermore, the nested PCR assay identified the mutation and generated conclusive cases for FXS, indicating that this assay is beneficial for the diagnosis of FXS patients. In conclusion, these outcomes indicate that nested PCR assay is a reliable and easier method for diagnosis of FXS, which may be used for the diagnosis of FXS patients.

Fragile X syndrome and fragile X-associated disorders

Fragile X syndrome (FXS) is caused by a full mutation on the FMR1 gene and a subsequent lack of FMRP, the protein product of FMR1. FMRP plays a key role in regulating the translation of many proteins involved in maintaining neuronal synaptic connections; its deficiency may result in a range of intellectual disabilities, social deficits, psychiatric problems, and dysmorphic physical features. A range of clinical involvement is also associated with the FMR1 premutation, including fragile X-associated tremor ataxia syndrome, fragile X-associated primary ovarian insufficiency, psychiatric problems, hypertension, migraines, and autoimmune problems. Over the past few years, there have been a number of advances in our knowledge of FXS and fragile X-associated disorders, and each of these advances offers significant clinical implications. Among these developments are a better understanding of the clinical impact of the phenomenon known as mosaicism, the revelation that various types of mutations can cause FXS, and improvements in treatment for FXS.

Molecular biomarkers predictive of sertraline treatment response in young children with fragile X syndrome

OBJECTIVES

Several neurotransmitters involved in brain development are altered in fragile X syndrome (FXS), the most common monogenic cause of autism spectrum disorder (ASD). Serotonin plays a vital role in synaptogenesis and postnatal brain development. Deficits in serotonin synthesis and abnormal neurogenesis were shown in young children with autism, suggesting that treating within the first years of life with a selective serotonin reuptake inhibitor might be the most effective time. In this study we aimed to identify molecular biomarkers involved in the serotonergic pathway that could predict the response to sertraline treatment in young children with FXS.

METHODS

Genotypes were determined for several genes involved in serotonergic pathway in 51 children with FXS, ages 24-72months. Correlations between genotypes and deviations from baseline in primary and secondary outcome measures were modeled using linear regression models.

RESULTS

A significant association was observed between a BDNF polymorphism and improvements for several clinical measures, including the Clinical Global Impression scale (P=0.008) and the cognitive T score (P=0.017) in those treated with sertraline compared to those in the placebo group. Additionally, polymorphisms in the MAOA, Cytochrome P450 2C19 and 2D6, and in the 5-HTTLPR gene showed a significant correlation with some of the secondary measures included in this study.

CONCLUSION

This study shows that polymorphisms of genes involved in the serotonergic pathway could play a potential role in predicting response to sertraline treatment in young children with FXS. Larger studies are warranted to confirm these initial findings.

Pharmacotherapy for Fragile X Syndrome: Progress to Date

To date, no drug is approved for the treatment of Fragile X Syndrome (FXS) although many drugs are used to manage challenging behaviors from a symptomatic perspective in this population. While our understanding of FXS pathophysiology is expanding, efforts to devise targeted FXS-specific treatments have had limited success in placebo-controlled trials. Compounds aimed at rectifying excessive glutamate and deficient gamma-aminobutyric acid (GABA) neurotransmission, as well as other signaling pathways known to be affected by Fragile X Mental Retardation Protein (FMRP) are under various phases of development in FXS. With the failure of several metabotropic glutamate receptor subtype 5 (mGlur5) selective antagonists under clinical investigation, no clear single treatment appears to be greatly effective. These recent challenges call into question various aspects of clinical study design in FXS. More objective outcome measures are under development and validation. Future trials will likely be aimed at correcting multiple pathways known to be disrupted by the loss of FMRP. This review offers a brief summary of the prevalence, phenotypic characteristics, genetic causes and molecular functions of FMRP in the brain (as these have been extensively reviewed elsewhere), discusses the most recent finding in FXS drug development, and summarizes FXS trials utilizing symptomatic treatment.

The neurobiology of the Prader-Willi phenotype of fragile X syndrome

Fragile X syndrome (FXS) is the most common inherited cause of intellectual disability and autism, caused by a CGG expansion to greater than 200 repeats in the promoter region of FMR1 on the bottom of the X chromosome. A subgroup of individuals with FXS experience hyperphagia, lack of satiation after meals and severe obesity, this subgroup is referred to have the Prader-Willi phenotype of FXS. Prader-Willi syndrome is one of the most common genetic severe obesity disorders known and it is caused by the lack of the paternal 15q11-13 region. Affected individuals suffer from hyperphagia, lack of satiation, intellectual disability, and behavioral problems. Children with fragile X syndrome Prader-Willi phenotye and those with Prader Willi syndrome have clinical and molecular similarities reviewed here which will impact new treatment options for both disorders.

A Randomized, Double-Blind, Placebo-Controlled Trial of Low-Dose Sertraline in Young Children With Fragile X Syndrome

OBJECTIVE

Observational studies and anecdotal reports suggest that sertraline, a selective serotonin reuptake inhibitor, may improve language development in young children with fragile X syndrome (FXS).

METHODS

The authors evaluated the efficacy of 6 months of treatment with low-dose sertraline in a randomized, double-blind, placebo-controlled trial in 52 children with FXS aged 2 to 6 years.

RESULTS

Eighty-one subjects were screened for eligibility, and 57 were randomized to sertraline (27) or placebo (30). Two subjects from the sertraline arm and 3 from the placebo arm discontinued. Intent-to-treat analysis showed no difference from placebo on the primary outcomes: the Mullen Scales of Early Learning (MSEL) expressive language (EL) age equivalent and Clinical Global Impression Scale-Improvement. However, analyses of secondary measures showed significant improvements, particularly in motor and visual perceptual abilities and social participation. Sertraline was well tolerated, with no difference in side effects between sertraline and placebo groups. No serious adverse events occurred.

CONCLUSION

This randomized controlled trial of 6 months of sertraline treatment showed no primary benefit with respect to early EL development and global clinical improvement. However, in secondary exploratory analyses, there were significant improvements seen on motor and visual perceptual subtests, the cognitive T score sum on the MSEL, and on one measure of social participation on the Sensory Processing Measure-Preschool. Furthermore, post hoc analysis found significant improvement in early EL development as measured by the MSEL among children with autism spectrum disorder on sertraline. Treatment appears safe for this 6-month period in young children with FXS, but the authors do not know the long-term side effects of this treatment. These results warrant further studies of sertraline in young children with FXS using refined outcome measures as well as longer term follow-up studies to address long-term side effects of low-dose sertraline in early childhood.

Molecular medicine of fragile X syndrome: based on known molecular mechanisms

BACKGROUND

Extensive research on fragile X mental retardation gene knockout mice and mutant Drosophila models has largely expanded our knowledge on mechanism-based treatment of fragile X syndrome (FXS). In light of these findings, several clinical trials are now underway for therapeutic translation to humans.

DATA SOURCES

Electronic literature searches were conducted using the PubMed database and ClinicalTrials.gov. The search terms included "fragile X syndrome", "FXS and medication", "FXS and therapeutics" and "FXS and treatment". Based on the publications identified in this search, we reviewed the neuroanatomical abnormalities in FXS patients and the potential pathogenic mechanisms to monitor the progress of FXS research, from basic studies to clinical trials.

RESULTS

The pathological mechanisms of FXS were categorized on the basis of neuroanatomy, synaptic structure, synaptic transmission and fragile X mental retardation protein (FMRP) loss of function. The neuroanatomical abnormalities in FXS were described to motivate extensive research into the region-specific pathologies in the brain responsible for FXS behavioural manifestations. Mechanism-directed molecular medicines were classified according to their target pathological mechanisms, and the most recent progress in clinical trials was discussed.

CONCLUSIONS

Current mechanism-based studies and clinical trials have greatly contributed to the development of FXS pharmacological therapeutics. Research examining the extent to which these treatments provided a rescue effect or FMRP compensation for the developmental impairments in FXS patients may help to improve the efficacy of treatments.

Translational Mouse Models of Autism: Advancing Toward Pharmacological Therapeutics

Animal models provide preclinical tools to investigate the causal role of genetic mutations and environmental factors in the etiology of autism spectrum disorder (ASD). Knockout and humanized knock-in mice, and more recently knockout rats, have been generated for many of the de novo single gene mutations and copy number variants (CNVs) detected in ASD and comorbid neurodevelopmental disorders. Mouse models incorporating genetic and environmental manipulations have been employed for preclinical testing of hypothesis-driven pharmacological targets, to begin to develop treatments for the diagnostic and associated symptoms of autism. In this review, we summarize rodent behavioral assays relevant to the core features of autism, preclinical and clinical evaluations of pharmacological interventions, and strategies to improve the translational value of rodent models of autism.

Identification of a male with fragile X syndrome through newborn screening

A pilot newborn screening (NBS) study for fragile X syndrome was recently conducted at the University of California, Davis Medical Center. The screening study identified a case of a male with the full mutation completely methylated and no detectable expression of the fragile X mental retardation-1 (FMR1) gene. The patient was initially seen in clinic at the MIND Institute, for medical follow-up and a genetic counseling session at the chronological age of 3 months. Since then, he has been seen in clinic every six months for follow up, medical examination and developmental assessments. Longitudinally administered developmental testing of the infant has revealed persistent delays in development, consistent with fragile X syndrome. Cascade testing revealed that the patient's mother and two siblings also have the full mutation. The patient has been receiving speech and language therapy, combined with physical and occupational therapies on a weekly basis since the age of one year. He is currently being treated with 2.5 mg of sertraline, which has been demonstrated to be helpful for improving language in young children with the syndrome.

Emerging pharmacologic treatment options for fragile X syndrome

Fragile X syndrome (FXS) is the most common single gene cause of intellectual disability and autism spectrum disorder. Caused by a silenced fragile X mental retardation 1 gene and the subsequent deficiency in fragile X mental retardation protein, patients with FXS experience a range of physical, behavioral, and intellectual debilitations. The FXS field, as a whole, has recently met with some challenges, as several targeted clinical trials with high expectations of success have failed to elucidate significant improvements in a variety of symptom domains. As new clinical trials in FXS are planned, there has been much discussion about the use of the commonly used clinical outcome measures, as well as study design considerations, patient stratification, and optimal age range for treatment. The evidence that modification of these drug targets and use of these failed compounds would prove to be efficacious in human clinical study were rooted in years of basic and translational research. There are questions arising as to the use of the mouse models for studying FXS treatment development. This issue is twofold: many of the symptom domains and molecular and biochemical changes assessed and indicative of efficacy in mouse model study are not easily amenable to clinical trials in people with FXS because of the intolerability of the testing paradigm or a lack of noninvasive techniques (prepulse inhibition, sensory hypersensitivity, startle reactivity, or electrophysiologic, biochemical, or structural changes in the brain); and capturing subtle yet meaningful changes in symptom domains such as sociability, anxiety, and hyperactivity in human FXS clinical trials is challenging with the currently used measures (typically parent/caregiver rating scales). Clinicians, researchers, and the pharmaceutical industry have all had to take a step back and critically evaluate the way we think about how to best optimize future investigations into pharmacologic FXS treatments. As new clinical trials are coming down the drug discovery pipeline, it is clear that the field is moving in a direction that values the development of molecular biomarkers, less subjective quantitative measures of symptom improvement, and rating scales developed specifically for use in FXS in conjunction with drug safety. While summarizing preclinical evidence, where applicable, and discussing challenges in FXS treatment development, this review details both completed clinical trials for the targeted and symptomatic treatment of FXS and introduces novel projects on the cusp of clinical trial investigation.

Treatment of the psychiatric problems associated with fragile X syndrome

PURPOSE OF REVIEW

This work reviews recent research regarding treatment of fragile X syndrome (FXS), the most common inherited cause of intellectual disability and autism spectrum disorder. The phenotype includes anxiety linked to sensory hyperarousal, hyperactivity, and attentional problems consistent with attention deficit hyperactivity disorder and social deficits leading to autism spectrum disorder in 60% of boys and 25% of girls with FXS.

RECENT FINDINGS

Multiple targeted treatments for FXS have rescued the phenotype of the fmr1 knockout mouse, but few have been beneficial to patients with FXS. The failure of the metabotropic glutamate receptor 5 antagonists falls on the heels of the failure of Arbaclofen's efficacy in children and adults with autism or FXS. In contrast, efficacy has been demonstrated in a controlled trial of minocycline in children with FXS. Minocycline lowers the abnormally elevated levels of matrix metalloproteinase 9 in FXS. Acamprosate and lovastatin have been beneficial in open-label trials in FXS. The first 5 years of life may be the most efficacious time for intervention when combined with behavioral and/or educational interventions.

SUMMARY

Minocycline, acamprosate, lovastatin, and sertraline are treatments that can be currently prescribed and have shown benefit in children with FXS. Use of combined medical and behavioral interventions will likely be most efficacious for the treatment of FXS.

Serotonin dysregulation in Fragile X Syndrome: implications for treatment

Fragile X Syndrome (FXS) is a trinucleotide repeat disorder that results in the silencing of the Fragile X Mental Retardation 1 gene (FMR1), leading to a lack of the FMR1 protein (FMRP). FMRP is an mRNA-binding protein that regulates the translation of hundreds of mRNAs important for synaptic plasticity. Several of these pathways have been identified and have guided the development of targeted treatments for FXS. Here we present evidence that serotonin is dysregulated in FXS and treatment with the selective serotonin reuptake inhibitor (SSRI) sertraline may be beneficial for individuals with FXS, particularly in early childhood.

Fragile X syndrome

Fragile X Syndrome (FXS) is a genetic disease due to a CGG trinucleotide expansion, named full mutation (greater than 200 CGG repeats), in the fragile X mental retardation 1 gene locus Xq27.3; which leads to an hypermethylated region in the gene promoter therefore silencing it and lowering the expression levels of the fragile X mental retardation 1, a protein involved in synaptic plasticity and maturation. Individuals with FXS present with intellectual disability, autism, hyperactivity, long face, large or prominent ears and macroorchidism at puberty and thereafter. Most of the young children with FXS will present with language delay, sensory hyper arousal and anxiety. Girls are less affected than boys, only 25% have intellectual disability. Given the genomic features of the syndrome, there are patients with a number of triplet repeats between 55 and 200, known as premutation carriers. Most carriers have a normal IQ but some have developmental problems. The diagnosis of FXS has evolved from karyotype with special culture medium, to molecular techniques that are more sensitive and specific including PCR and Southern Blot. During the last decade, the advances in the knowledge of FXS, has led to the development of investigations on pharmaceutical management or targeted treatments for FXS. Minocycline and sertraline have shown efficacy in children.

Maternal predictors of anxiety risk in young males with fragile X

Children with fragile X syndrome (FXS) demonstrate high rates of anxiety disorders, with 65-83% meeting diagnostic criteria. The severity of anxiety symptoms in FXS has been shown to be partially predicted by elevated negative affect across early childhood [Tonnsen et al. (2013a); J Abnorm Child Psychol 41:267-280]. This association suggests that biologically driven vulnerability emerges early in development, as is reported in non-clinical populations. However, anxiety emergence is likely moderated by multifaceted genetic, biological and environmental risk and protective factors. Mothers with the FMR1 premutation have been shown to exhibit elevated parenting stress and internalizing symptoms, which have each been associated with child behavior problems [Bailey et al. (2008a); Am J Med Genet Part A 146A:2060-2069 and Bailey et al. (2008b) Am J Med Genet Part A 146A:720-729]. Despite these findings, it is unclear whether maternal factors directly relate to anxiety vulnerability in high-risk children with FXS, a question essential to informing targeted, family-sensitive treatment. The present study examines how maternal protective and risk factors relate to child inhibition reflected in (1) child anxiety symptoms, (2) child trajectories of negative affect, and (3) the association between child anxiety and negative affect. Primary predictors include maternal parenting stress, indicators of mental health risk (anxiety and depressive symptoms), and maternal optimism. We also examine genetic correlates in mothers (CGG repeats, activation ratio, mRNA). Our findings suggest that behavioral inhibition in young children with FXS is associated with higher parenting stress and lower optimism, and higher parenting stress is associated with lower maternal X-activation ratio. These findings underscore the need for family-sensitive treatment strategies for anxiety disorders in children with FXS.

Psychiatric symptoms in boys with fragile X syndrome: a comparison with nonsyndromic autism spectrum disorder

In the present study, we examined the profile of psychiatric symptoms in boys with fragile X syndrome (FXS) using a parent report instrument. In addition, by comparing boys with FXS to boys with nonsyndromic autism spectrum disorder (ASD) utilizing multiple matching strategies, we examined between-group differences in the types of psychiatric symptoms observed and in the strength of their concurrent associations. Across all matching strategies, symptoms of manic/hyperactive behaviors and general anxiety were more frequently reported for boys with FXS than for boys with nonsyndromic ASD. Results also indicated a positive association between social avoidance and general anxiety in FXS that was stronger than that observed in nonsyndromic ASD across all matching strategies. Theoretical and treatment implications are discussed.

Newborn screening for fragile X syndrome

Fragile X syndrome (FXS), caused by a trinucleotide expansion (>200 CGG repeats) in the fragile X mental retardation gene (FMR1), is currently not included in newborn screening (NBS) panels in the United States as it does not meet the standards for recommendation. Although in the past few years FXS has met many of the criteria for population screening and studies have shown that NBS for FXS is feasible, the idea is still controversial and the debate is open. The recent advances in genomic testing as well as groundbreaking advances in targeted treatment for FXS have been challenging the dogma and principle of the national NBS program: screen only if you can intervene. Arguments in favor of NBS include benefits of early intervention and follow-up for the identified baby, which would justify NBS even in the absence of medical benefit to the child. In addition, the extended family members may benefit from genetic and reproductive counseling, informed decision making before a subsequent pregnancy, and access to treatment and services. However, communicating the results and the potential consequences to families is a challenge and could lead to a heavy psychosocial burden. A controversial issue is the identification of premutation carriers (55-200 CGG repeats), because it not only can lead to information on the reproductive possibility of having a child with FXS but also leads to information about personal health risks associated with the premutation. Yet, knowledge of carrier status could stimulate and encourage lifestyle changes and preventive measures likely to reduce the risk of medical problems reported in premutation carriers. If NBS for FXS is developed, it must be carried out with clear awareness of the potential impact on the lives of the children, and it should be done after counseling and parents' informed consent. Importantly, the infrastructure to support testing, counseling, treatment, and follow-up will have to be made available to the families.

The challenges of clinical trials in fragile X syndrome

RATIONALE

Advances in understanding the underlying mechanisms of conditions such as fragile X syndrome (FXS) and autism spectrum disorders have revealed heterogeneous populations. Recent trials of novel FXS therapies have highlighted several challenges including subpopulations with possibly differential therapeutic responses, the lack of specific outcome measures capturing the full range of improvements of patients with FXS, and a lack of biomarkers that can track whether a specific mechanism is responsive to a new drug and whether the response correlates with clinical improvement.

OBJECTIVES

We review the phenotypic heterogeneity of FXS and the implications for clinical research in FXS and other neurodevelopmental disorders.

RESULTS

Residual levels of fragile X mental retardation protein (FMRP) expression explain in part the heterogeneity in the FXS phenotype; studies indicate a correlation with both cognitive and behavioral deficits. However, this does not fully explain the extent of phenotypic variance observed or the variability of drug response. Post hoc analyses of studies involving the selective mGluR5 antagonist mavoglurant and the GABAB agonist arbaclofen have uncovered significant therapeutic responses following patient stratification according to FMR1 promoter methylation patterns or baseline severity of social withdrawal, respectively. Future studies designed to quantify disease modification will need to develop new strategies to track changes effectively over time and in multiple symptom domains.

CONCLUSION

Appropriate selection of patients and outcome measures is central to optimizing future clinical investigations of these complex disorders.

Pharmacotherapy for the core symptoms in autistic disorder: current status of the research

The current review covers extant literature on pharmacotherapy for core symptoms of autism. The core symptoms of autism include impairments in social interaction and communication, as well as the presence of restricted and repetitive behaviors. There are no known efficacious treatments for the core social symptoms, although effects on repetitive behaviors are indicated with some data. While studies of fenfluramine, secretin, opiates, and mood stabilizers generally find no effect, mixed results suggest more research is needed on antidepressants and atypical antipsychotics. Newer lines of research, including cholinergic and glutamatergic agents and oxytocin, will be of considerable interest in the future. However, research on the treatment of core symptoms is plagued by limitations in study design, statistical power, and other issues inherent to the study of treatments for autism (e.g., heterogeneity of the disorder) that continue to prevent the elucidation of efficacious treatments.

Prevention and early intervention for behaviour problems in children with developmental disabilities

PURPOSE OF REVIEW

To review the recent evidence regarding early intervention and prevention studies for children with developmental disabilities and behaviour problems from 2011 to 2013. Recent advances in the field are discussed and important areas for future research are highlighted.

RECENT FINDINGS

Recent reviews and studies highlight the utility of antecedent interventions and skills training interventions for reducing behaviour problems. There is preliminary evidence for the effectiveness of parent training interventions when delivered in minimally sufficient formats or in clinical settings. Two recent studies have demonstrated the utility of behavioural interventions for children with genetic causes of disability.

SUMMARY

Various forms of behavioural and parent training interventions are effective at reducing the behaviour problems in children with developmental disabilities. However, research on prevention and early intervention continues to be relatively scarce. Further large-scale dissemination studies and effectiveness studies in clinical or applied settings are needed.