Behavioral phenotype of fragile X syndrome in adolescence and adulthood

Age-related trajectories of health and cognition in mothers of children with developmental disabilities: Longitudinal findings from two independent studies

Developmental disabilities are a heterogenous group of disorders characterized by impairments in physical functioning, learning, language, behavior, and self-care (Zablotsky et al., 2019). Parenting a child with a developmental disability can be a profound source of stress, particularly for mothers. This atypical parenting experience can begin with the birth of the child, or soon thereafter, and continues over the life course, often extending six decades or more. However, there is limited research on the impact of this parenting role across the full adult life course - from mothers' early years of parenting through older age. Here we draw on data from two separate studies, one a national study of mothers of children with a range of developmental conditions (n = 96) and the other a community study of mothers of children with autism (n = 391). We used an accelerated longitudinal design to estimate mothers' trajectories of health, mental health, and cognitive functioning beginning in their 20s and extending until their 80s or beyond, and conducted a series of cohort and sensitivity analyses. Together, the results of analyses of these two studies revealed very similar patterns across a number of important outcomes. The inclusion in one of the studies of a nationally representative comparison group of mothers whose children did not have disabilities (n = 1,181) indicated that after around age 65, aging in mothers of children with developmental disabilities differed from the norm, suggesting the 'wear-and-tear' effects of this common form of stressful parenting.

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.

Novel p.Arg534del Mutation and MTHFR C667T Polymorphism in Fragile X Syndrome (FXS) With Autism Spectrum Phenotype: A Case Report

Fragile X syndrome (FXS) presents with autism spectrum disorder (ASD), intellectual disability, developmental delay, seizures, hypotonia during infancy, joint laxity, behavioral issues, and characteristic facial features. The predominant mechanism is due to CGG trinucleotide repeat expansion of more than 200 repeats in the 5'UTR (untranslated region) of FMR1 (Fragile X Messenger Ribonucleoprotein 1) causing promoter methylation and transcriptional silencing. However, not all patients presenting with the characteristic phenotype and point/frameshift mutations with deletions in FMR1 have been described in the literature. It is believed that < 1% of cases are caused by point mutations. Genetic and functional testing of point mutations in FXS has yielded insights on KH domain RNA-binding properties of FMRP (Fragile X Messenger Ribonucleoprotein Protein) and nuclear export of the protein. Here, we report a c.1599_1601del p.Arg534del novel mutation in FMR1 with homozygous C677T MTHFR polymorphism in a 12-year-old boy. He presents with unique phenotype of FXS with ASD, developmental delay, nonverbal learning disorder (NVLD), overall IQ in the 5th percentile with above average verbal IQ (66th percentile), difficulties with quantitative reasoning, dyspraxia, below average visual-spatial skills (2nd percentile), difficulty with social pragmatics and social understanding, and executive dysfunction. He has a strong aptitude for music and exceptional aural skills. Identification of novel variants has helped in understanding functional aspects of FMRP. In addition, it aids families in genetic counseling and in administering therapies for children with FXS who present with atypical features.

Behavioral, neurotransmitter and transcriptomic analyses in male and female Fmr1 KO mice

Introduction

Fragile X syndrome is an inherited X-linked disorder associated with intellectual disabilities that begin in childhood and last a lifetime. The symptoms overlap with autism spectrum disorder, and the syndrome predominantly affects males. Consequently, FXS research tends to favor analysis of social behaviors in males, leaving a gap in our understanding of other behavioral traits, especially in females.

Methods

We used a mouse model of FXS to analyze developmental, behavioral, neurochemical, and transcriptomic profiles in males and females.

Results

Our behavioral assays demonstrated locomotor hyperactivity, motor impulsivity, increased "approach" behavior in an approach-avoidance assay, and deficits in nest building behavior. Analysis of brain neurotransmitter content revealed deficits in striatal GABA, glutamate, and serotonin content. RNA sequencing of the ventral striatum unveiled expression changes associated with neurotransmission as well as motivation and substance use pathways. Sex differences were identified in nest building behavior, striatal neurotransmitter content, and ventral striatal gene expression.

Discussion

In summary, our study identified sex differences in specific behavioral, neurotransmitter, and gene expression phenotypes and gene set enrichment analysis identified significant enrichment of pathways associated with motivation and drug reward.

FMR1 Protein Expression Correlates with Intelligence Quotient in Both Peripheral Blood Mononuclear Cells and Fibroblasts from Individuals with an FMR1 Mutation

Fragile X syndrome (FXS) is the most common heritable form of intellectual disability and is caused by CGG repeat expansions exceeding 200 (full mutation). Such expansions lead to hypermethylation and transcriptional silencing of the fragile X messenger ribonucleoprotein 1 (FMR1) gene. As a consequence, little or no FMR1 protein (FMRP) is produced; absence of the protein, which normally is responsible for neuronal development and maintenance, causes the syndrome. Previous studies have demonstrated the causal relationship between FMRP levels and cognitive abilities in peripheral blood mononuclear cells (PBMCs) and dermal fibroblast cell lines of patients with FXS. However, it is arguable whether PBMCs or fibroblasts would be the preferred surrogate for measuring molecular markers, particularly FMRP, to represent the cognitive impairment, a core symptom of FXS. To address this concern, CGG repeats, methylation status, FMR1 mRNA, and FMRP levels were measured in both PBMCs and fibroblasts derived from 66 individuals. The findings indicated a strong association between FMR1 mRNA expression levels and CGG repeat numbers in PBMCs of premutation males after correcting for methylation status. Moreover, FMRP expression levels from both PBMCs and fibroblasts of male participants with a hypermethylated full mutation and with mosaicism demonstrated significant association between the intelligence quotient levels and FMRP levels, suggesting that PBMCs may be preferable for FXS clinical studies, because of their greater accessibility.

Case Series: Vestibular Migraines in Fragile X Premutation Carriers

BACKGROUND

Vestibular migraine (VM) is one of the most common causes of recurrent vertigo and presents with a history of spontaneous or positional vertigo with a history of migraine headaches. While research has identified a high prevalence of migraine headaches and vestibular deficits among fragile X premutation carriers, there has been no discussion about VM within this population.

OBJECTIVE

This case series and review seeks to describe the clinical characteristics and pathophysiology of VM among individuals with the fragile X premutation. We also seek to discuss treatment and future steps in addressing VM in this population.

METHODS

A review of the literature regarding vestibular migraine and presentation of migraine headaches and vestibular deficits among premutation carriers was performed. A detailed clinical history of migraine headaches and vertigo was obtained from three patients with the fragile X premutation seen by the senior author (RJH).

RESULTS

All three cases first developed symptoms of migraine headaches earlier in life, with the development of VM near menopause. Two of the three cases developed progressive balance issues following the development of VM. All three cases found that their VM episodes were improved or resolved with pharmacological and/or lifestyle interventions.

CONCLUSIONS

It is important to recognize VM among premutation carriers because beneficial treatments are available. Future studies are needed regarding the prevalence of VM and the relationship to subsequent FXTAS. The pathophysiology of VM remains uncertain but possibilities include mitochondrial abnormalities, cranial nerve VIII toxicity secondary to neurotoxic protein accumulation, and calcitonin gene-related peptide (CGRP) signaling dysfunction due to altered levels of fragile X messenger ribonucleoprotein (FMRP).

ADHD and ASD symptoms in young males with fragile X syndrome: associations with early trajectories of inhibitory control

Inhibitory control (IC), the ability to suppress inappropriate responses, emerges late in the first year of life and improves across typical development, concurrent with brain maturation. The development of IC is critical to various social-emotional and behavioral functions, with IC difficulties being linked to numerous neurodevelopmental disorders, including attention-deficit/hyperactivity disorder (ADHD) and autism spectrum disorder (ASD). Fragile X syndrome (FXS) is a single-gene disorder characterized by IC difficulties, and elevated rates of ADHD and ASD, making it a useful model for understanding the early development and consequences of IC. In this longitudinal study, we characterized IC trajectories across multiple time points between 16 and 71 months of age in young males with FXS (n = 79) relative to neurotypical (NT) controls (n=49). To explore the association between behavioral outcomes and IC, we identified a subsample of 50 children with longitudinal IC data and an outcome assessment for ADHD and ASD symptoms at age 5 (FXS: n = 26, NT: n = 24). Results indicated that, compared to their NT peers, young males with FXS exhibit differences in IC as early as 24 months, with group differences increasing through age 5. Additionally, we determined that lower IC levels at 24 months were associated with later ADHD symptoms and a decreasing slope in IC over time was associated with later ASD symptoms in male children with FXS. These findings help refine early developmental phenotypes of FXS and highlight IC as a potential target for early detection and intervention of ASD and ADHD symptoms in male children with FXS.

Systematic Review: Emotion Dysregulation in Syndromic Causes of Intellectual and Developmental Disabilities

OBJECTIVE

To summarize the current state of the literature regarding emotion dysregulation (ED) in syndromic intellectual disabilities (S-IDs) in 6 of the most common forms of S-IDs-Down syndrome, fragile X syndrome (FXS), tuberous sclerosis complex, Williams syndrome, Prader-Willi syndrome, and Angelman syndrome-and to determine future research directions for identification and treatment of ED.

METHOD

PubMed bibliographic database was searched from date of inception to May 2021. PRISMA 2020 guidelines were followed with the flowchart, table of included studies, list of excluded studies, and checklist provided. Filters applied included human research and English. Only original research articles were included in the final set, but review articles were used to identify secondary citations of primary studies. All articles were reviewed for appropriateness by 2 authors and summarized. Inclusion criteria were met by 145 articles (Down syndrome = 29, FXS = 55, tuberous sclerosis complex = 11, Williams syndrome = 18, Prader-Willi syndrome = 24, Angelman syndrome = 8).

RESULTS

Each syndrome review was summarized separately and further subdivided into articles related to underlying neurobiology, behaviors associated with ED, assessment, and targeted intervention. FXS had the most thorough research base, followed by Down syndrome and Prader-Willi syndrome, with the other syndromes having more limited available research. Very limited research was available regarding intervention for all disorders except FXS.

CONCLUSION

Core underlying characteristics of S-IDs appear to place youth at higher risk for ED, but further research is needed to better assess and treat ED in S-IDs. Future studies should have a standard assessment measure of ED, such as the Emotion Dysregulation Inventory, and explore adapting established curricula for ED from the neurotypical and autism spectrum disorder fields.

Transactional relationships between maternal requesting and responsivity, adolescent compliance, and task demands in fragile X syndrome

BACKGROUND

Males with fragile X syndrome (FXS) may have difficulty with social communication and language in addition to behavioral concerns such as noncompliance to maternal requests. Mothers vary in how they pose requests to their children, and contextual demands may also be a factor in compliance. This study examined the relationships between maternal requesting behaviors, maternal responsivity, child compliance, and task demands in adolescent males with FXS.

METHODS

35 mother-son dyads completed three interactive tasks during in-home visits (puzzle, iPad games, snack). The adolescents also completed assessments of language and autism symptoms. The three interactive tasks were video-recorded, and behavior-by-behavior coding and transcription was completed.

RESULTS

Comparing between tasks, mothers requested a behavior most often during the snack task and used a higher proportion of indirect requests during the iPad task. Adolescents were largely compliant across tasks, with average compliance equal to 70%. Adolescent compliance was predicted by maternal request frequency such that mothers who used more requests had adolescent sons who were less compliant. Maternal responsivity was higher for mothers of adolescents with FXS-only compared to those with FXS and high autism symptoms.

CONCLUSIONS AND IMPLICATIONS

Task demands may have influenced maternal requesting, which in turn may have impacted adolescent compliance. Compliance with requests is important for both social and educational aspects of life, and further study of requesting and compliance in FXS is needed to identify effective teaching and behavioral intervention methods.

"Corp-Osa-Mente", a Combined Psychosocial-Neuropsychological Intervention for Adolescents and Young Adults with Fragile X Syndrome: An Explorative Study

Fragile X Syndrome is the most known inherited form of intellectual disability due to an expansion in the full mutation range (>200 CGG repeats) of the promoter region of the FMR1 gene located on X chromosomes leading to gene silencing. Despite clear knowledge of the cognitive-behavioral phenotype of FXS and the necessity of tailored interventions, empirical research on the effectiveness of behavioral treatments among patients with FXS is still lacking, with studies on adolescents and young adults even more insufficient. Here we present "Corposamente", a combined psychosocial-neuropsychological intervention conducted with a group of ten adolescents/young adults with FXS, who are non-ASD and without significant behavioral problems. In total, 20 sessions were performed, alternating between online and face-to-face meetings. At the end of the intervention, participants, family members and participants' educators anonymously completed a survey that was designed around key areas of improvement as well as treatment satisfaction. The survey results indicated that participants improved mostly in their ability to cope with negative emotions and that occupational intervention was considered the most effective technique both from families and participants. Our exploratory study suggests that group therapy for the management of the FXS cognitive-behavioral phenotype may be a promising approach to continue to pursue, mostly in adolescence when the environmental demands increase.

Profiles of autism characteristics in thirteen genetic syndromes: a machine learning approach

BACKGROUND

Phenotypic studies have identified distinct patterns of autistic characteristics in genetic syndromes associated with intellectual disability (ID), leading to diagnostic uncertainty and compromised access to autism-related support. Previous research has tended to include small samples and diverse measures, which limits the generalisability of findings. In this study, we generated detailed profiles of autistic characteristics in a large sample of > 1500 individuals with rare genetic syndromes.

METHODS

Profiles of autistic characteristics based on the Social Communication Questionnaire (SCQ) scores were generated for thirteen genetic syndrome groups (Angelman n = 154, Cri du Chat n = 75, Cornelia de Lange n = 199, fragile X n = 297, Prader-Willi n = 278, Lowe n = 89, Smith-Magenis n = 54, Down n = 135, Sotos n = 40, Rubinstein-Taybi n = 102, 1p36 deletion n = 41, tuberous sclerosis complex n = 83 and Phelan-McDermid n = 35 syndromes). It was hypothesised that each syndrome group would evidence a degree of specificity in autistic characteristics. To test this hypothesis, a classification algorithm via support vector machine (SVM) learning was applied to scores from over 1500 individuals diagnosed with one of the thirteen genetic syndromes and autistic individuals who did not have a known genetic syndrome (ASD; n = 254). Self-help skills were included as an additional predictor.

RESULTS

Genetic syndromes were associated with different but overlapping autism-related profiles, indicated by the substantial accuracy of the entire, multiclass SVM model (55% correctly classified individuals). Syndrome groups such as Angelman, fragile X, Prader-Willi, Rubinstein-Taybi and Cornelia de Lange showed greater phenotypic specificity than groups such as Cri du Chat, Lowe, Smith-Magenis, tuberous sclerosis complex, Sotos and Phelan-McDermid. The inclusion of the ASD reference group and self-help skills did not change the model accuracy.

LIMITATIONS

The key limitations of our study include a cross-sectional design, reliance on a screening tool which focuses primarily on social communication skills and imbalanced sample size across syndrome groups.

CONCLUSIONS

These findings replicate and extend previous work, demonstrating syndrome-specific profiles of autistic characteristics in people with genetic syndromes compared to autistic individuals without a genetic syndrome. This work calls for greater precision of assessment of autistic characteristics in individuals with genetic syndromes associated with ID.

Examining Phenotypic Differences in Gaze Avoidance Between Autism Spectrum Disorder and Fragile X Syndrome

We examined potential phenotypic differences in eye gaze avoidance exhibited by boys with autism spectrum disorder (ASD) and boys with fragile X syndrome (FXS). In Study 1, the Eye Contact Avoidance Scale (ECAS) was administered to caregivers of boys aged 7-18 years with FXS (n = 148), ASD (n = 168), and mixed developmental disabilities (MDD; n = 128). In Study 2, subsets of boys with FXS (n = 31) and boys with ASD (n = 25) received a brief behavioral treatment probe to improve eye contact. Results showed that boys with FXS obtained significantly higher scores on the ECAS compared to boys with ASD and MDD. Exposure to the brief behavioral treatment probe resulted in significant decreases in scores for boys with FXS, but not for boys with ASD.

Verbal Ability, Behavior Problems, and Mother-Child Relationship Quality in Autism Spectrum Disorder

This study examined differences in mother-child relationship quality and parent-rated child behavior problems based on child verbal status (i.e., minimally verbal versus verbal) in mothers and their adolescent and adult children with autism spectrum disorder (n = 219 dyads; child M_age = 25.38 years, SD = 10.22). Relationship quality was assessed via parent-reported maternal burden and mother-child closeness, and coded speech samples ascertaining maternal critical and positive remarks regarding the child. Groups did not differ in relationship quality. The verbal group was more likely to display disruptive and socially inappropriate behaviors, but otherwise the groups did not differ in behavior problems. Verbal status moderated the relationship between behavior problems and negative (maternal burden, critical remarks) but not positive (mother-child closeness, positive remarks) aspects of relationship quality.

Attention/Deficit Hyperactivity Disorder in Adolescent and Young Adult Males With Fragile X Syndrome

This study characterized the rates of attention-deficit/hyperactivity disorder (ADHD) in adolescent and young adult males with fragile X syndrome (FXS) using a multi-method approach integrating a DSM-based parent interview (Children's Interview for Psychiatric Syndromes; P-ChIPS, Fristad et al., 1998) and a parent rating scale (Child Behavior Checklist; CBCL, Achenbach, 2001). Thirty-one males with FXS, aged 16-24 years, participated. Forty-two percent met DSM-5 criteria for ADHD and 35% exceeded the CBCL cut-offs. Agreement between the two classification methods was fair (κ = 0.38). Autism symptom severity and nonverbal cognitive ability did not predict ADHD diagnoses/symptoms. Results show high rates of ADHD in males with FXS during late adolescence and young adulthood, which are not accounted for by impaired nonverbal cognitive skills or autism symptom severity. DSM-based ADHD-specific scales are recommended over broadband symptom scales to improve accurate identification.

Pragmatic Profiles of Adults with Fragile X Syndrome and Williams Syndrome

Linguistic phenotypes of individuals with Fragile X (FXS) and Williams (WS) syndromes exhibit various degrees of pragmatic impairment, involving difficulties in social communication and in adapting to conversational principles. The goal of the present study was to explore syndrome-specific pragmatic profiles of adults with FXS and WS based on the assessment of the observance of Gricean maxims of conversation. The participants were 12 Spanish-speaking adults (6 FXS/6 WS), without a diagnosis of ASD, whose extensive naturalistic conversations (71,859 words) were transcribed and coded with the CHILDES/TALKBANK tools and the PREP-CORP pragmatic protocol. Violations of the maxims of conversation were analyzed, and indexes of cooperation and conversational response were obtained. Both groups showed reduced verbal production and repetitive dysfluencies; prominent features in the FXS profile were higher proportion of non-contingent language, perseverations of topic and form, and impulsive conversational responses; in the WS profile, salient characteristics were higher proportion of tangential utterances, reformulations, and conversational responses reflecting overly literal interpretation. Pragmatic profiles of violation of conversational maxims reflect specific communication skills impaired in adults with FXS and WS and raise the need for assessment and intervention methods that specifically address their social communication abilities.

Fragile X premutation carrier screening in Pakistani preconception women in primary care consultation

PURPOSE

Women of reproductive age who carry fragile X premutation (PM) alleles have 56 to 200 CGG repeats in the 5'-untranslated region of FMR1 gene are at increased risk for producing children with intellectual disabilities (ID) or autism spectrum disorders (ASD) due to expansion of PM alleles to full mutation alleles (> 200 repeats) during maternal transmission.

METHODS

In present study fragile X PM carrier screening was performed in total 808 women who were consulting primary health care centers for preconception care in Khyber Pakhtunkhwa region of Pakistan between April, 2018 and December, 2020. Polymerase chain reaction (PCR) was performed for detection of PM carrier women and the CGG repeats number was confirmed by Southern blotting and capillary electrophoresis.

RESULTS

The prevalence rate for PM carriers among preconception women was found to be 0.7% that was contributed by 0.5% women in risk group (RG1) with family history of ID and 0.2% in risk group 2 (RG2) with family history of ASD. PM carrier women had at least one affected child or sibling. In addition, the preconception women with FMR1 PM alleles were found to be at increased risk for primary ovary insufficiency (RG1: P = 0.0265, RG2: P = 0.0389), postpartum depression (RG1: P = 0.0240, RG2: P = 0.0501) and neuropsychiatric disorders (RG1: P = 0.0389, RG2: P = 0.0432).

CONCLUSIONS

Current study provides first evidence of fragile X PM carrier screening in Pakistani preconception women in primary care consultation. Findings of current study may help to improve preconception care and to reduce burden of fragile X associated disorders in our population.

Behavior Problems and Social Competence in Fragile X Syndrome: A Systematic Review

Fragile X syndrome (FXS) causes intellectual disability and is the known leading cause of autism. Common problems in FXS include behavior and social problems. Along with syndromic characteristics and autism comorbidity, environmental factors might influence these difficulties. This systematic review focuses on the last 20 years of studies concerning behavior and social problems in FXS, considering environmental and personal variables that might influence both problems. Three databases were reviewed, leading to fifty-one studies meeting the inclusion criteria. Attention deficit hyperactivity disorder (ADHD) problems remain the greatest behavior problems, with behavioral problems and social competence being stable during the 20 years. Some developmental trajectories might have changed due to higher methodological control, such as aggressive behavior and attention problems. The socialization trajectory from childhood to adolescence remains unclear. Comorbidity with autism in individuals with FXS increased behavior problems and worsened social competence profiles. At the same time, comparisons between individuals with comorbid FXS and autism and individuals with autism might help define the comorbid phenotype. Environmental factors and parental characteristics influenced behavior problems and social competence. Higher methodological control is needed in studies including autism symptomatology and parental characteristics. More studies comparing autism in FXS with idiopathic autism are needed to discern differences between conditions.

Autism Symptoms in Children and Young Adults With Fragile X Syndrome, Angelman Syndrome, Tuberous Sclerosis Complex, and Neurofibromatosis Type 1: A Cross-Syndrome Comparison

OBJECTIVE

The etiology of autism spectrum disorder (ASD) remains unclear, due to genetic heterogeneity and heterogeneity in symptoms across individuals. This study compares ASD symptomatology between monogenetic syndromes with a high ASD prevalence, in order to reveal syndrome specific vulnerabilities and to clarify how genetic variations affect ASD symptom presentation.

METHODS

We assessed ASD symptom severity in children and young adults (aged 0-28 years) with Fragile X Syndrome (FXS, n = 60), Angelman Syndrome (AS, n = 91), Neurofibromatosis Type 1 (NF1, n = 279) and Tuberous Sclerosis Complex (TSC, n = 110), using the Autism Diagnostic Observation Schedule and Social Responsiveness Scale. Assessments were part of routine clinical care at the ENCORE expertise center in Rotterdam, the Netherlands. First, we compared the syndrome groups on the ASD classification prevalence and ASD severity scores. Then, we compared individuals in our syndrome groups with an ASD classification to a non-syndromic ASD group (nsASD, n = 335), on both ASD severity scores and ASD symptom profiles. Severity scores were compared using MANCOVAs with IQ and gender as covariates.

RESULTS

Overall, ASD severity scores were highest for the FXS group and lowest for the NF1 group. Compared to nsASD, individuals with an ASD classification in our syndrome groups showed less problems on the instruments' social domains. We found a relative strength in the AS group on the social cognition, communication and motivation domains and a relative challenge in creativity; a relative strength of the NF1 group on the restricted interests and repetitive behavior scale; and a relative challenge in the FXS and TSC groups on the restricted interests and repetitive behavior domain.

CONCLUSION

The syndrome-specific strengths and challenges we found provide a frame of reference to evaluate an individual's symptoms relative to the larger syndromic population and to guide treatment decisions. Our findings support the need for personalized care and a dimensional, symptom-based diagnostic approach, in contrast to a dichotomous ASD diagnosis used as a prerequisite for access to healthcare services. Similarities in ASD symptom profiles between AS and FXS, and between NF1 and TSC may reflect similarities in their neurobiology. Deep phenotyping studies are required to link neurobiological markers to ASD symptomatology.

Daily Living Skills in Adolescent and Young Adult Males With Fragile X Syndrome

By adulthood, most males with fragile X syndrome (FXS) require support to navigate day-to-day settings. The present study cross-sectionally: (1) characterized the profile of daily living skills in males with FXS and (2) examined associated participant characteristics (i.e., fragile X mental retardation protein [FMRP] expression, nonverbal cognition, language, autism symptomatology, and anxiety symptomatology) using the Waisman-Activities of Daily Living questionnaire. Males with FXS (n = 57, ages 15-23 years) needed more help/support in the areas of domestic and community daily livings skills, than in the area of personal daily living skills. Significant associations were observed between reduced daily living skills and lower nonverbal cognition, receptive language, expressive language, and increased autism symptomatology. Receptive language emerged as the strongest unique predictor of daily living skill performance.

Change in Behavior Problems from Childhood Through Adolescence for Children with Fragile X Syndrome

In this study, we examined trajectories of specific domains of behavior problems (i.e., attention problems, depression/anxiety, and aggressive behavior) from age 6 to 18 in a sample of 55 children with fragile X syndrome. We also examined autism status and early parenting as predictors of subsequent behavioral trajectories. We found that attention problems and aggressive behavior declined steadily from childhood through adolescence whereas anxious/depressed behavior demonstrated relative stability over the same period. Youth with highly flexible mothers displayed more optional trajectories of improvement in attention problems.

Parental Reports on Early Autism Behaviors in Their Children with Fragile X Syndrome as a Function of Infant Feeding

This study evaluates the prevalence of autistic behaviors in fragile X syndrome as a function of infant diet. Retrospective survey data from the Fragile X Syndrome Nutrition Study, which included data on infant feeding and caregiver-reported developmental milestones for 190 children with fragile X syndrome enrolled in the Fragile X Online Registry with Accessible Database (FORWARD), were analyzed. Exploratory, sex-specific associations were found linking the use of soy-based infant formula with worse autistic behaviors related to language in females and self-injurious behavior in males. These findings prompt prospective evaluation of the effects of soy-based infant formula on disease comorbidities in fragile X syndrome, a rare disorder for which newborn screening could be implemented if there was an intervention. Gastrointestinal problems were the most common reason cited for switching to soy-based infant formula. Thus, these findings also support the study of early gastrointestinal problems in fragile X syndrome, which may underly the development and severity of disease comorbidities. In conjunction with comorbidity data from the previous analyses of the Fragile X Syndrome Nutrition Study, the findings indicate that premutation fragile X mothers should be encouraged to breastfeed.

Autism spectrum disorder in females with fragile X syndrome: a systematic review and meta-analysis of prevalence

BACKGROUND

Whilst up to 60% of males with fragile X syndrome (FXS) meet criteria for autism spectrum disorder (ASD), the prevalence and nature of ASD in females with FXS remains unclear.

METHOD

A systematic literature search identified papers reporting ASD prevalence and/or symptomatology in females with FXS.

RESULTS AND CONCLUSION

Meta-analysis suggested that rates of ASD for females with FXS are reliably higher than for females in the general population (a random effects model estimated weighted average prevalence at 14%, 95% CI 13-18%). Whilst papers highlighted a number of social and repetitive difficulties for females with FXS, characteristic profiles of impairment are not clear. Possible associations between ASD traits and IQ, and between ASD and levels of fragile X mental retardation protein, are suggested, but data are equivocal.

Verbal Ability, Behavior Problems, and Mother-Child Relationship Quality in Autism Spectrum Disorder

This study examined differences in mother-child relationship quality and parent-rated child behavior problems based on child verbal status (i.e., minimally verbal versus verbal) in mothers and their adolescent and adult children with autism spectrum disorder (n = 219 dyads; child M_age = 25.38 years, SD = 10.22). Relationship quality was assessed via parent-reported maternal burden and mother-child closeness, and coded speech samples ascertaining maternal critical and positive remarks regarding the child. Groups did not differ in relationship quality. The verbal group was more likely to display disruptive and socially inappropriate behaviors, but otherwise the groups did not differ in behavior problems. Verbal status moderated the relationship between behavior problems and negative (maternal burden, critical remarks) but not positive (mother-child closeness, positive remarks) aspects of relationship quality.

Maternal Mental Health and Parenting Stress and Their Relationships to Characteristics of the Child With Fragile X Syndrome

Although previous research supports the notion that characteristics of both the child and the mother impact maternal well-being and parenting stress in mothers of children with FXS, more work is needed in which self-report measures are supplemented by physiological measures of stress and well-being. The inclusion of physiological measures, such as heart rate variability (HRV), may provide a window into the biological origins and consequences of maternal perceptions of their experiences, including the challenges of raising a child with developmental challenges. The proposed project, therefore, involved the collection of multimodal assessment data from mothers and their school-aged children with FXS. Further, given the importance of understanding how mothers of youth with FXS are faring in their everyday environment, the present study collected all data using telehealth procedures and wearable technology. Participants were 20 biological mothers and their children with FXS between the ages of 6 and 11 years. We measured maternal mental health and parenting stress through self-report as well as through HRV as a more objective measure of psychological well-being. We also examined the associations between these variables and child characteristics such as externalizing and internalizing behaviors as well as autism symptomatology. We found significant support for an elevated rate of depressive symptoms in the sample of mothers (35%) and some potential indicators for heightened rates of anxiety (15%) when compared to normed samples and rates in the general population. We also found that the mothers presented with an atypical HRV profile akin to those experiencing depression or chronic stress, although limitations of the present measure suggest the need for additional confirmatory research. Further, we found that child externalizing behaviors were the primary correlates of maternal well-being. These findings contribute to the growing body of literature regarding the unique challenges faced by these mother-child dyads and supports the importance of increasing the availability of services available to these mothers, not only for meeting the needs of their children's development and behavior, but in supporting their own well-being as well.

Growing up with Fragile X Syndrome: Concerns and Care Needs of Young Adult Patients and Their Parents

Little is known about care needs of young adults with Fragile X Syndrome (FXS). Patient-driven information is needed to improve understanding and support of young adults with FXS. A qualitative study was performed in 5 young adult patients (aged 18–30), and 33 parents of young adults. Concerns and care needs were categorized using the International Classification of Functioning, Disability, and Health. Results indicated concerns on 14 domains for males, and 13 domains for females, including physical, psychological and socio-economical issues. In both groups parents reported high stress levels and a lack of knowledge of FXS in adult care providers. This study revealed concerns on various domains, requiring gender-specific, multidisciplinary transitional care and adult follow-up for patients with FXS.

Trajectories of Change in the Behavioral and Health Phenotype of Adolescents and Adults with Fragile X Syndrome and Intellectual Disability: Longitudinal Trends Over a Decade

This study examined trajectories of daily living skills, behavior problems, body mass index (BMI), and health conditions spanning nearly a decade in adolescents and adults with fragile X syndrome (N = 134; age range at study end = 19-49 years), examining influences of sex and autism spectrum disorder (ASD) symptoms. Hierarchical linear modeling revealed early increases in daily living skills, with decreases at older ages. Behavior problems became less severe over time, with some increases at older ages. Individuals gained weight and had increasing health problems over time. Fewer ASD symptoms were associated with greater daily living skills and fewer behavior problems at study start. This study offers some of the first prospective quantitative analyses of behavioral and health life course trajectories in FXS.

Abnormal development of auditory responses in the inferior colliculus of a mouse model of Fragile X Syndrome

Sensory processing abnormalities are frequently associated with autism spectrum disorders, but the underlying mechanisms are unclear. Here we studied auditory processing in a mouse model of Fragile X Syndrome (FXS), a leading known genetic cause of autism and intellectual disability. Both humans with FXS and the Fragile X mental retardation gene (Fmr1) knockout (KO) mouse model show auditory hypersensitivity, with the latter showing a strong propensity for audiogenic seizures (AGS) early in development. Because midbrain abnormalities cause AGS, we investigated whether the inferior colliculus (IC) of the Fmr1 KO mice shows abnormal auditory processing compared with wild-type (WT) controls at specific developmental time points. Using antibodies against neural activity marker c-Fos, we found increased density of c-Fos+ neurons in the IC, but not auditory cortex, of Fmr1 KO mice at P21 and P34 following sound presentation. In vivo single-unit recordings showed that IC neurons of Fmr1 KO mice are hyperresponsive to tone bursts and amplitude-modulated tones during development and show broader frequency tuning curves. There were no differences in rate-level responses or phase locking to amplitude-modulated tones in IC neurons between genotypes. Taken together, these data provide evidence for the development of auditory hyperresponsiveness in the IC of Fmr1 KO mice. Although most human and mouse work in autism and sensory processing has centered on the forebrain, our new findings, along with recent work on the lower brainstem, suggest that abnormal subcortical responses may underlie auditory hypersensitivity in autism spectrum disorders.NEW & NOTEWORTHY Autism spectrum disorders (ASD) are commonly associated with sensory sensitivity issues, but the underlying mechanisms are unclear. This study presents novel evidence for neural correlates of auditory hypersensitivity in the developing inferior colliculus (IC) in Fmr1 knockout (KO) mouse, a mouse model of Fragile X Syndrome (FXS), a leading genetic cause of ASD. Responses begin to show genotype differences between postnatal days 14 and 21, suggesting an early developmental treatment window.

The Persistence of Self-injurious and Aggressive Behavior in Males with Fragile X Syndrome Over 8 Years: A Longitudinal Study of Prevalence and Predictive Risk Markers

Self-injurious and aggressive behaviors are common in fragile X syndrome (FXS). However, little is known about the persistence of these behaviors and associated risk markers. We established the prevalence and persistence of self-injurious and aggressive behaviors over eight years in males with FXS, and associations with risk markers. Results showed 77% and 69% persistence rates for self-injurious and aggressive behavior, respectively. Baseline levels of repetitive behavior predicted persistent self-injurious behavior. Chronological age, impulsivity and overactivity were associated with persistent aggressive behavior but only impulsivity predicted persistence. This is the first study to document the persistence of self-injurious and aggressive behavior in FXS over the medium to long term and to identify behavioral risk markers that might facilitate targeted early intervention.

Mass Spectrometry for the Study of Autism and Neurodevelopmental Disorders

Mass spectrometry (MS) has been increasingly used to study central nervous system (CNS) disorders, including autism spectrum disorders (ASDs). The first studies of ASD using MS focused on the identification of external toxins, but current research is more directed at understanding endogenous protein changes that occur in ASD (ASD proteomics). This chapter focuses on how MS has been used to study ASDs, with particular focus on proteomic analysis. Other neurodevelopmental disorders have been investigated using this technique, including genetic syndromes associated with autism such as fragile X syndrome (FXS) and Smith-Lemli-Opitz Syndrome (SLOS).

Unaffected siblings of adolescents and adults with fragile X syndrome: Effects on maternal well-being

The present study investigated the effects of children without disabilities on maternal physical and mental health in families with adolescents or adults with fragile X syndrome. Mothers with the FMR1 premutation (N = 87) reported on behavior problems and functional limitations of their adolescent or adult child with fragile X syndrome and their own physical and mental health. Mothers also provided a blood sample to determine FMR1 CGG repeat length. The proportion of unaffected children in the family significantly buffered the effect of both child behavior problems and functional limitations on maternal self-rated health, such that having a higher proportion of unaffected children in the family had a protective effect on maternal health when the target child had more severe behavior problems and functional limitations. There was a similar buffering process for maternal depressive symptoms but at a trend level. Additionally, maternal CGG repeat length had a significant curvilinear association with self-rated health, indicating that mothers with midrange repeat lengths reported the poorest health, whereas mothers with lower and higher repeat lengths in the premutation range reported better health. The data suggest that unaffected children in the family may be an important resource for premutation carrier mothers. Findings are consistent with previous research indicating that mothers with varying levels of genetic liability have variable risk for health problems. (PsycINFO Database Record (c) 2019 APA, all rights reserved).

More Than IQ: Executive Function Explains Adaptive Behavior Above and Beyond Nonverbal IQ in Youth With Autism and Lower IQ

Adaptive behavior is a critical metric for measuring outcomes in those with autism spectrum disorder (ASD). Executive function skills predict adaptive behavior in youth with ASD with average or higher IQ; however, no study has examined this relationship in ASD with lower IQ (IQ ≤ 75). The current study evaluated whether executive function predicted adaptive behavior in school-age youth with ASD with lower IQ, above and beyond nonverbal IQ. We examined adaptive behavior and executive function through informant report on 100 youth with ASD with lower IQ. Executive function skills explained variance in adaptive social and communication domains, beyond nonverbal IQ; monitoring skills played a significant role. This research suggests that malleable skills like executive function may contribute to functional outcomes in this population.

ASD Comorbidity in Fragile X Syndrome: Symptom Profile and Predictors of Symptom Severity in Adolescent and Young Adult Males

Many males with FXS meet criteria for ASD. This study was designed to (1) describe ASD symptoms in adolescent and young adult males with FXS (n = 44) and (2) evaluate the contributions to ASD severity of cognitive, language, and psychiatric factors, as well as FMRP (the protein deficient in FXS). A few ASD symptoms on the ADOS-2 were universal in the sample. There was less impairment in restricted and repetitive behaviors (RRB) than in the social affective (SA) domain. The best predictor of overall ASD severity and SA severity was expressive syntactic ability. RRB severity was best predicted by the psychiatric factors. Implications for clinical practice and for understanding the ASD comorbidity in FXS are discussed.

Prevalence and Predictors of Anxiety Disorders in Adolescent and Adult Males with Autism Spectrum Disorder and Fragile X Syndrome

Anxiety disorders affect ~ 15-20% of youths without neurodevelopmental disorders, with persons having autism spectrum disorder (ASD) and fragile X syndrome (FXS) at elevated risk for anxiety disorders. Few studies have compared rates and predictors of anxiety disorders in adolescents with FXS or ASD. This study directly compares rates, predictors, and medication of anxiety disorders between age-matched, male adolescents with FXS (n = 31) or ASD (n = 20). Results indicate that 51.6% of FXS and 50.0% of ASD adolescents met criteria for an anxiety disorder. Cognitive scores and ASD severity did not predict anxiety. Of those with anxiety, ~ 40% of the FXS and 20% of the ASD participants were prescribed medications for anxiety.

Friendships and social participation as markers of quality of life of adolescents and adults with fragile X syndrome and autism

Friendships and social participation are key domains of quality of life for individuals with intellectual disabilities. This study examined the friendships, social and recreational activities, and family social networks of individuals with intellectual disabilities from two distinct diagnostic groups: individuals diagnosed with fragile X syndrome (n = 81) compared with those diagnosed with autistic disorder (n = 226). Within each diagnostic group, individuals in two developmental stages were compared: adolescence and adulthood. Quality of life in friendships and social participation domains was notably low for individuals with fragile X and those with autism. Individuals with fragile X had more friendships and a less negative social impact on the family than individuals with autism. Across both groups, adolescents spent less time with friends and neighbors, and more time in exercising, than did adults.

Dendritic Spines in Early Postnatal Fragile X Mice Are Insensitive to Novel Sensory Experience

Autism spectrum disorders are often associated with atypical sensory processing and sensory hypersensitivity, which can lead to maladaptive behaviors, such as tactile defensiveness. Such altered sensory perception in autism spectrum disorders could arise from disruptions in experience-dependent maturation of circuits during early brain development. Here, we tested the hypothesis that synaptic structures of primary somatosensory cortex (S1) neurons in Fragile X syndrome (FXS), which is a common inherited cause of autism, are not modulated by novel sensory information during development. We used chronic in vivo two-photon microscopy to image dendritic spines and axon "en passant" boutons of layer 2/3 pyramidal neurons in S1 of male and female WT and Fmr1 KO mice, a model of FXS. We found that a brief (overnight) exposure to dramatically enhance sensory inputs in the second postnatal week led to a significant increase in spine density in WT mice, but not in Fmr1 KO mice. In contrast, axon "en passant" boutons dynamics were impervious to this novel sensory experience in mice of both genotypes. We surmise that the inability of Fmr1 KO mice to modulate postsynaptic dynamics in response to increased sensory input, at a time when sensory information processing first comes online in S1 cortex, could play a role in altered sensory processing in FXS.SIGNIFICANCE STATEMENT Very few longitudinal in vivo imaging studies have investigated synaptic structure and dynamics in early postnatal mice. Moreover, those studies tend to focus on the effects of sensory input deprivation, a process that rarely occurs during normal brain development. Early postnatal imaging experiments are critical because a variety of neurodevelopmental disorders, including those characterized by autism, could result from alterations in how circuits are shaped by incoming sensory inputs during critical periods of development. In this study, we focused on a mouse model of Fragile X syndrome and demonstrate how dendritic spines are insensitive to a brief period of novel sensory experience.

Toward the Language Oscillogenome

Language has been argued to arise, both ontogenetically and phylogenetically, from specific patterns of brain wiring. We argue that it can further be shown that core features of language processing emerge from particular phasal and cross-frequency coupling properties of neural oscillations; what has been referred to as the language ‘oscillome.’ It is expected that basic aspects of the language oscillome result from genetic guidance, what we will here call the language ‘oscillogenome,’ for which we will put forward a list of candidate genes. We have considered genes for altered brain rhythmicity in conditions involving language deficits: autism spectrum disorders, schizophrenia, specific language impairment and dyslexia. These selected genes map on to aspects of brain function, particularly on to neurotransmitter function. We stress that caution should be adopted in the construction of any oscillogenome, given the range of potential roles particular localized frequency bands have in cognition. Our aim is to propose a set of genome-to-language linking hypotheses that, given testing, would grant explanatory power to brain rhythms with respect to language processing and evolution.

Understanding the pediatric psychiatric phenotype of 22q11.2 deletion syndrome

The purpose of this article is to provide an overview of current insights into the neurodevelopmental and psychiatric manifestations of 22q11.2 deletion syndrome (22q11DS) in children and adolescents. The pediatric neuropsychiatric expression of 22q11DS is characterized by high variability, both interindividual and intraindividual (different expressions over the lifespan). Besides varying levels of intellectual disability, the prevalence of autism spectrum disorders, attention deficit disorders, anxiety disorders, and psychotic disorders in young individuals with 22q11DS is significantly higher than in the general population, or in individuals with idiopathic intellectual disability. Possible explanations for this observed phenotypic variability will be discussed, including genetic pleiotropy, gene-environment interactions, the age-dependency of phenotypes, but also the impact of assessment and ascertainment bias as well as the limitations of our current diagnostic classification system. The implications inferred by these observations aforementioned bear direct relevance to both scientists and clinicians. Observations regarding the neuropsychiatric manifestations in individuals with 22q11DS exemplify the need for a dimensional approach to neuropsychiatric assessment, in addition to our current categorical diagnostic classification system. The potential usefulness of 22q11DS as a genetic model to study the early phases of schizophrenia as well as the phenomenon of neuropsychiatric pleiotropy observed in many CNV's will be delineated. From a clinical perspective, the importance of regular neuropsychiatric evaluations with attention to symptoms not always captured in diagnostic categories and of maintaining equilibrium between individual difficulties and competencies and environmental demands will be discussed.

Mothers' perspectives on challenging behaviours in their children with fragile X syndrome

BACKGROUND

Individuals with intellectual and developmental disabilities are more likely to engage in problem behaviours than peers with typical development. The purpose of this study was to provide descriptive and qualitative information about problem behaviours in children with fragile X syndrome (FXS) and how families respond to these behaviours.

METHOD

We examined interview responses from 53 mothers of 9-year-old children with FXS.

RESULTS

Defiance, tantrums, inattention, stereotypy, and aggression were the most frequently reported problem behaviours of children with FXS. Stereotypy, physical aggression, self-injury, and elopement were reported more often by mothers of children with dual diagnoses of FXS and autism than by mothers of children with a single diagnosis of FXS.

CONCLUSIONS

Results indicated that for many families, by 9 years of age, problem behaviours led to frustration and altered family activities.

Overactivity, impulsivity and repetitive behaviour in males with fragile X syndrome: contrasting developmental trajectories in those with and without elevated autism symptoms

BACKGROUND

Hyperactivity and repetitive behaviour are characteristic features of fragile X syndrome (FXS). However, little is known about the influence of autism symptomatology on how these characteristics develop over time. We investigate the profiles and developmental trajectories of overactivity, impulsivity and repetitive behaviour, in males with FXS over three time points spanning 8 years.

METHOD

Participants formed two subgroups, those who displayed elevated symptoms of autism at Time 1 (n = 37; M_age  = 16.32; age range = 6.61-43.51) and those who did not (n = 32; M_age  = 8.43; age range = 8.94-47.49).

RESULTS

Participants without elevated symptoms of autism showed a reduction in impulsivity and repetitive questioning over time, whereas those with elevated symptoms of autism did not. Differences between the two subgroups in several topographies of repetitive behaviour emerged at Time 3 only.

CONCLUSIONS

These results further understanding of the relationship between autistic phenomenology and behavioural characteristics in FXS.

A comparison of functional academic and daily living skills in males with fragile X syndrome with and without autism

BACKGROUND

Adaptive behaviors, such as functional academic and daily living skills, are critical for independence in adults with intellectual and developmental disabilities. However, little is known about these skills in fragile X syndrome (FXS), the most common form of inherited intellectual disability.

AIMS

The purposes of this study were to describe the functional academic and daily living skills of males diagnosed with FXS across different age groups and compare skill attainment by autism status and other common co-occurring conditions.

METHODS AND PROCEDURES

We used survey methods to assess parent-reported functional academic and daily living skills in 534 males with FXS. Functional academic skills included time and schedules, money, math, reading, and writing skills. Daily living skills included hygiene, cooking, laundry and housekeeping, transportation, and safety skills.

OUTCOMES AND RESULTS

Analyses examined functional academic and daily living skills in a cross-sectional sample of males between ages 5 and 67. Differences in skill attainment were found by child age, co-morbid autism status, total number of co-occurring conditions, and respondent education. Functional academic and daily living skills were predictive of community employment and independent living.

CONCLUSIONS AND IMPLICATIONS

These data provide important information on the mastery of both foundational and more complex adaptive skills in males with FXS. Both functional academic and daily living skills were predictive of measures of independence above and beyond other child and family characteristics. These findings point to the need to focus interventions to support the attainment of independence in males with FXS.

Health Profiles of Mosaic Versus Non-mosaic FMR1 Premutation Carrier Mothers of Children With Fragile X Syndrome

The FMR1 premutation is of increasing interest to the FXS community, as questions about a primary premutation phenotype warrant research attention. 100 FMR1 premutation carrier mothers (mean age = 58; 67–138 CGG repeats) of adults with fragile X syndrome were studied with respect to their physical and mental health, motor, and neurocognitive characteristics. We explored the correlates of CGG repeat mosaicism in women with expanded alleles. Mothers provided buccal swabs from which DNA was extracted and the FMR1 CGG genotyping was performed (Amplidex Kit, Asuragen). Mothers were categorized into three groups: Group 1: premutation non-mosaic (n = 45); Group 2: premutation mosaic (n = 41), and Group 3: premutation/full mutation mosaic (n = 14). Group 2 mothers had at least two populations of cells with different allele sizes in the premutation range besides their major expanded allele. Group 3 mothers had a very small population of cells in the full mutation range (>200 CGGs) in addition to one or multiple populations of cells with different allele sizes in the premutation range. Machine learning (random forest) was used to identify symptoms and conditions that correctly classified mothers with respect to mosaicism; follow-up comparisons were made to characterize the three groups. In categorizing mosaicism, the random forest yielded significantly better classification than random classification, with overall area under the receiver operating characteristic curve (AUROC) of 0.737. Among the most important symptoms and conditions that contributed to the classification were anxiety, menopause symptoms, executive functioning limitations, and difficulty walking several blocks, with the women who had full mutation mosaicism (Group 3) unexpectedly having better health. Although only 14 premutation carrier mothers in the present sample also had a small population of full mutation cells, their profile of comparatively better health, mental health, and executive functioning was unexpected. This preliminary finding should prompt additional research on larger numbers of participants with more extensive phenotyping to confirm the clinical correlates of low-level full mutation mosaicism in premutation carriers and to probe possible mechanisms.

Medication use by adolescents and adults with fragile X syndrome

BACKGROUND

The behavioural challenges and medical conditions associated with fragile X syndrome (FXS) can lead to increased need for medications.

METHOD

This longitudinal study examined the use of prescription medications for psychotropic and non-psychotropic purposes by adolescents and adults with FXS drawn from a North American community sample (N = 105). Odds and probabilities of continuing or discontinuing medication were calculated. Predictors of medication use were calculated.

RESULTS

More than two-thirds took psychotropic medication, and about one-quarter took non-psychotropic medication. Over a 3-year period, those who initially took prescription medications were considerably more likely to remain on medications than to stop. Individuals with more autism symptoms, more behavioural problems, a mental health diagnosis, and greater family income were significantly more likely to use psychotropic medication 3 years later. Individuals who had more health problems, a mental health diagnosis, and were female were more likely to use non-psychotropic medication over this time period.

CONCLUSIONS

Findings highlight the elevated and ongoing use of medication by individuals with FXS. Implications for social and behavioural research on FXS are discussed.

Autism Symptoms in Fragile X Syndrome

Fragile X syndrome (FXS) is recognized as the most common genetic cause of intellectual disability and autism spectrum disorder (ASD). Although symptoms of ASD are frequently observed in patients with FXS, researchers have not yet clearly determined whether the symptoms in patients with FXS differ from the symptoms in patients without ASD or nonsyndromic ASD. Behavioral similarities and differences between FXS and ASD are important to improve our understanding of the causes and correlations of ASD with FXS. Based on the evidence presented in this review, individuals with FXS and comorbid ASD have more severe behavioral problems than individuals with FXS alone. However, patients with FXS and comorbid ASD exhibit less severe impairments in the social and communication symptoms than patients with nonsyndromic ASD. Individuals with FXS also present with anxiety and seizures in addition to comorbid ASD symptoms, and differences in these conditions are noted in patients with FXS and ASD. This review also discusses the role of fragile X mental retardation 1 protein (FMRP) in FXS and ASD phenotypes.

Lessons learned from studying syndromic autism spectrum disorders

Syndromic autism spectrum disorders represent a group of childhood neurological conditions, typically associated with chromosomal abnormalities or mutations in a single gene. The discovery of their genetic causes has increased our understanding of the molecular pathways critical for normal cognitive and social development. Human studies have revealed that the brain is particularly sensitive to changes in dosage of various proteins from transcriptional and translational regulators to synaptic proteins. Investigations of these disorders in animals have shed light on previously unknown pathogenic mechanisms leading to the identification of potential targets for therapeutic intervention. The demonstration of reversibility of several phenotypes in adult mice is encouraging, and brings hope that with novel therapies, skills and functionality might improve in affected children and young adults. As new research reveals points of convergence between syndromic and nonsyndromic autism spectrum disorders, we believe there will be opportunities for shared therapeutics for this class of conditions.

Public Health Literature Review of Fragile X Syndrome

OBJECTIVES

The purpose of this systematic literature review is to describe what is known about fragile X syndrome (FXS) and to identify research gaps. The results can be used to help inform future public health research and provide pediatricians with up-to-date information about the implications of the condition for individuals and their families.

METHODS

An electronic literature search was conducted, guided by a variety of key words. The search focused on 4 areas of both clinical and public health importance: (1) the full mutation phenotype, (2) developmental trajectories across the life span, (3) available interventions and treatments, and (4) impact on the family. A total of 661 articles were examined and 203 were included in the review.

RESULTS

The information is presented in the following categories: developmental profile (cognition, language, functional skills, and transition to adulthood), social-emotional profile (cooccurring psychiatric conditions and behavior problems), medical profile (physical features, seizures, sleep, health problems, and physiologic features), treatment and interventions (educational/behavioral, allied health services, and pharmacologic), and impact on the family (family environment and financial impact). Research gaps also are presented.

CONCLUSIONS

The identification and treatment of FXS remains an important public health and clinical concern. The information presented in this article provides a more robust understanding of FXS and the impact of this complex condition for pediatricians. Despite a wealth of information about the condition, much work remains to fully support affected individuals and their families.

Automated screening for Fragile X premutation carriers based on linguistic and cognitive computational phenotypes

Millions of people globally are at high risk for neurodegenerative disorders, infertility or having children with a disability as a result of the Fragile X (FX) premutation, a genetic abnormality in FMR1 that is underdiagnosed. Despite the high prevalence of the FX premutation and its effect on public health and family planning, most FX premutation carriers are unaware of their condition. Since genetic testing for the premutation is resource intensive, it is not practical to screen individuals for FX premutation status using genetic testing. In a novel approach to phenotyping, we have utilized audio recordings and cognitive profiling assessed via self-administered questionnaires on 200 females. Machine-learning methods were developed to discriminate FX premutation carriers from mothers of children with autism spectrum disorders, the comparison group. By using a random forest classifier, FX premutation carriers could be identified in an automated fashion with high precision and recall (0.81 F1 score). Linguistic and cognitive phenotypes that were highly associated with FX premutation carriers were high language dysfluency, poor ability to organize material, and low self-monitoring. Our framework sets the foundation for computational phenotyping strategies to pre-screen large populations for this genetic variant with nominal costs.

Decreased home cage movement and oromotor impairments in adult Fmr1-KO mice

Fragile X syndrome (FXS) is a common inherited disorder that significantly impacts family and patient day-to-day living across the entire life span. The childhood and adolescent behavioral consequences of FXS are well appreciated. However, there are significantly fewer studies (except those examining psychiatric comorbidities) assessing behavioral phenotypes seen in adults with FXS. Mice engineered with a genetic lesion of fragile X mental retardation 1 (Fmr1) recapitulate important molecular and neuroanatomical characteristics of FXS, and provide a means to evaluate adult behavioral phenotypes associated with FXS. We give the first description of baseline behaviors including feeding, drinking, movement and their circadian rhythms; all observed over 16 consecutive days following extensive environmental habituation in adult Fmr1-KO mutant mice. We find no genotypic changes in mouse food ingestion, feeding patterns, metabolism or circadian patterns of movement, feeding and drinking. After habituation, Fmr1-KO mice show significantly less daily movement during their active phase (the dark cycle). However, Fmr1-KO mice have more bouts of activity during the light cycle compared with wild types. In addition, Fmr1-KO mice show significantly less daily water ingestion during the circadian dark cycle, and this reduction in water intake is accompanied by a decrease in the amount of water ingested per lick. The observed water ingestion and circadian phenotypes noted in Fmr1-KO mice recapitulate known clinical aspects previously described in FXS. The finding of decreased movement in Fmr1-KO mice is novel, and suggests a dissociation between baseline and novelty-evoked activity for Fmr1-KO mice.

[Pilot study of psychiatric and social aspects of children and adolescents with fragile X syndrome]

Objective

The study describes the burden of psychosocial risks of mental illnesses and the ways in which children and adolescents with fragile X syndrome (FRX) can be treated.

Method

Data from a sample of 34 patients with FRX younger than 18 years stemming from a prospective multicenter (n = 11) registry study (EXPLAIN) were analyzed with regard to psychosocial burden and Treatment.

Results

One third of all participants reported having relatives who suffer from FRX. The majority of participants were suffering themselves from one kind or another mental or neurological problems. Younger participants (< 14 years) tended to suffer from atactic disorders, epileptic seizures, and autistic symptoms. These disorders were usually treated by psychotropic drugs supplemented by logopedic therapies and occupational therapies (more than once a month). In our sample, 96.3 % of the younger patients and more than 57.1 % of the older patients were still living with their parents.

Conclusions

Patients with FRX often suffer from additional neurological and mental disorders. For that reason, they should be diagnosed and treated early on.