A developmental approach to understanding Fragile X syndrome in females

Suppression of astrocyte BMP signaling improves fragile X syndrome molecular signatures and functional deficits

Fragile X syndrome (FXS) is a monogenic neurodevelopmental disorder with manifestations spanning molecular, neuroanatomical, and behavioral changes. Astrocytes contribute to FXS pathogenesis and show hundreds of dysregulated genes and proteins; targeting upstream pathways mediating astrocyte changes in FXS could therefore be a point of intervention. To address this, we focused on the bone morphogenetic protein (BMP) pathway, which is upregulated in FXS astrocytes. We generated a conditional KO (cKO) of Smad4 in astrocytes to suppress BMP signaling, and found this lessens audiogenic seizure severity in FXS mice. To ask how this occurs on a molecular level, we performed in vivo transcriptomic and proteomic profiling of cortical astrocytes, finding upregulation of metabolic pathways, and downregulation of secretory machinery and secreted proteins in FXS astrocytes, with these alterations no longer present when BMP signaling is suppressed. Functionally, astrocyte Smad4 cKO restores deficits in inhibitory synapses present in FXS auditory cortex. Thus, astrocytes contribute to FXS molecular and functional phenotypes, and targeting astrocytes can mitigate FXS symptoms.

A longitudinal investigation of pragmatic language across contexts in autism and related neurodevelopmental conditions

Background

Pragmatic language, or the use of language in social contexts, is a critical skill in daily life, supporting social interactions and the development of meaningful social relationships. Pragmatic language is universally impacted in autism spectrum disorder (ASD) and pragmatic deficits are also common in other neurodevelopmental conditions, particularly those related to ASD, such as fragile X syndrome (FXS). This study used a multi-method, longitudinal approach to characterize potentially unique pragmatic profiles across different neurodevelopmental disabilities, and across contexts that varied in degree of social demand. The utility of computational linguistic analyses, as an efficient tool for capturing pragmatic abilities, was also explored.

Methods

Pragmatic skills of boys with idiopathic ASD (ASD-O, n = 43), FXS with and without ASD (FXS-ASD, n = 57; FXS-O, n = 14), Down syndrome (DS, n = 22), and typical development (TD, n = 24) were compared using variables obtained from a standardized measure, narrative, and semi-naturalistic conversation at up to three time points.

Results

Pragmatic language was most significantly impacted among males with ASD-O and FXS-ASD across all three contexts, with more difficulties in the least structured context (conversation), and also some differences based on FXS comorbidity. Patterns of group differences were more nuanced for boys with FXS-O and DS, with context having less of an impact. Clinical groups demonstrated minimal changes in pragmatic skills with age, with some exceptions. Computational language measurement tools showed some utility for measuring pragmatic skills, but were not as successful as traditional methods at capturing differences between clinical groups.

Conclusion

Overlap and differences between ASD and other forms of neurodevelopmental disability in general, and between idiopathic and syndromic ASD in particular, have important implications for developing precisely tailored assessment and intervention approaches, consistent with a personalized medicine approach to clinical study and care in ASD.

Executive function, repetitive behaviour and restricted interests in neurodevelopmental disorders

BACKGROUND

Individuals with genetic syndromes show unique profiles of repetitive behaviours and restricted interests (RRBs). The executive dysfunction account of RRBs suggests that in autistic (AUT) individuals executive function impairments underpin RRBs, but not communication and social interaction autistic characteristics.

AIMS

To 1) describe profiles of behavioural manifestations of executive function (EF behaviours) and 2) explore the relationship between EF behaviours and autistic traits across individuals with Cornelia de Lange (CdLS), fragile X (FXS) and Rubinstein-Taybi syndromes (RTS), and AUT individuals.

METHOD

Carers completed the Behavior Rating Inventory of Executive Function - Preschool Version and the Social Communication Questionnaire. Data reporting on 25 individuals with CdLS (Mage = 18.60, SD = 8.94), 25 with FXS (Mage = 18.48, SD = 8.80), 25 with RTS (Mage = 18.60, SD = 8.65) and 25 AUT individuals (Mage = 18.52, SD = 8.65) matched on chronological age and adaptive ability were included in analyses.

RESULTS

All groups showed impairments across EF behaviours compared to two-to-three-year-old typically developing normative samples with no differences between groups. Different EF behaviours predicted RRBs in the syndrome groups with no associations found in the AUT group.

CONCLUSIONS

Syndrome related differences should be considered when developing targeted interventions that focus on EF behaviours and/or RRBs in these groups.

Mental Health Challenges, Parenting Stress, and Features of the Couple Relationship in Parents of Children With Fragile X Syndrome

BACKGROUND

Individuals with fragile X syndrome (FXS) have significant delays in cognition and language, as well as anxiety, symptoms of autism spectrum disorder, and challenging behaviors such as hyperactivity and aggression. Biological mothers of children with FXS, who are themselves FMR1 premutation or full mutation carriers, are at elevated risk for mental health challenges in addition to experiencing stress associated with parenting a child with significant disabilities. However, little is known about fathers in these families, including the ways in which parental well-being influences the mother-father relationship and the impact of child characteristics on paternal and couple functioning.

METHOD

The current study examined features of, and relationships between, parental well-being, couple well-being, and child functioning in 23 families of young boys with FXS. Mothers and fathers independently completed multiple questionnaires about their individual well-being, couple functioning, and child behavior. One parent per family also completed an interview about the child's adaptive skills.

RESULTS

Results suggest that both mothers and fathers in these families experience clinically significant levels of mental health challenges and elevated rates of parenting stress relative to the general population. Findings also indicate that the couples' relationship may be a source of strength that potentially buffers against some of the daily stressors faced by these families. Additionally, parents who reported less parenting stress had higher couples satisfaction and dyadic coping. Finally, parents of children with less severe challenging behaviors exhibited fewer mental health challenges, less parenting stress, and higher levels of both couples satisfaction and dyadic coping. Parents of children with higher levels of adaptive behavior also reported less parenting stress and higher couples satisfaction.

CONCLUSION

Overall, this study provides evidence that families of children with FXS need access to services that not only target improvements in the child's functioning, but also ameliorate parental stress. Family-based services that include both mothers and fathers would lead to better outcomes for all family members.

Concurrent Associations between Expressive Language Ability and Independence in Adolescents and Adults with Fragile X Syndrome

BACKGROUND

Few individuals with fragile X syndrome (FXS) successfully meet adult normative expectations in education, employment, peer relations, and habitation, although there is within-syndrome variability in this regard. The primary goal of this study was to determine whether expressive language skills contribute to the capacity for independent functioning in adulthood even after controlling for nonverbal cognitive ability.

METHODS

Participants were 18- to 23-year-olds with FXS. Expressive language was assessed using the psychometrically validated Expressive Language Sampling (ELS) conversation and narration procedures. The language produced was transcribed and analyzed to yield measures of expressive vocabulary, syntax, and intelligibility. Parents concurrently completed questionnaires on the independent functioning of the participants with FXS.

RESULTS

All three ELS measures were significantly corelated with multiple measures of independence. The magnitudes of the correlations were reduced when nonverbal IQ was controlled through partial correlation. Nonetheless, many of the partial correlations were medium to large and several were statistically significant.

CONCLUSIONS

Expressive language skills appear to contribute uniquely to the capacity for independence, although longitudinal data are needed to evaluate the possibility of a bidirectional relationship between these domains. Thus, language intervention may be a prerequisite for preparing youth with FXS for an independent adult life.

Pilot study of socio-emotional factors and adaptive behavior in young females with fragile X syndrome

Girls with Fragile-X-Syndrome (FXS) present high levels of social anxiety, social avoidance, extreme shyness, tendency to social isolation, poor eye contact, learning difficulties, and depression. The aims of the present study, which is based on a group of young females with FXS are: 1) to analyze the possible associations between emotion recognition, theory of mind, and social anxiety, and adaptive behavior, and emotional state; 2) to study the relationship between intelligence quotient (IQ) and adaptive behavior; and 3) to assess whether social anxiety is more prevalent in girls with FXS. The study has 40 female participants aged between 7 and 16 years (26 positive full mutation FXS and 14 as a control group). A neuropsychological assessment was conducted using the following tests: WISC-V, NEPSY-II, SENA, ADHD Rating Scale, BAS, and ABAS-II. In comparison with the control group, the group with FXS presented a greater association between IQ and self-direction ability, and between emotion recognition and leadership. The FXS group presented higher levels of social anxiety and shyness. In the group of girls with FXS, IQ may have prognostic value for both self-direction ability and social adaptation level.

Fragile X syndrome in young females: Influence of executive function on the neurocognitive profile and adaptive behavior

INTRODUCTION

The aim of this study is to describe the relationship between executive function (EF) and performance in different areas of the neurocognitive profile in young girls with Fragile-X-Syndrome (FXS).

METHOD

A neuropsychological assessment was carried out to 40 female participants aged 7-16 years (26 FXS, 14 control group).

RESULTS

Regarding intellectual ability, in the group of girls with FXS 3.84 % of the participants obtained IQ scores in the range of moderate ID (IQ 35-40 to 49), 46.15 % in the range of mild ID (IQ 50-70), 38.46 % in the borderline range (IQ 70-85), and 11.53 % within the average range (IQ > 85). EF was found to have a greater influence on adaptive behavior, arithmetic ability, theory of mind, leadership, social integration, social competence, and anxiety/shyness in the group with FXS.

CONCLUSIONS

In girls with FXS, EF showed a greater influence on adaptive behavior, arithmetic ability, and social domain.

Language in young females with fragile X syndrome: Influence on the neurocognitive profile and adaptive behavior

Fragile X syndrome (FXS) is the leading cause of inherited intellectual disability. The objective of this research is to analyze the relationship between linguistic functions and performance of the following neuropsychological functions: executive, quantitative reasoning, social perception, behavior, social skills, and adaptive behavior. A neuropsychological and behavioral evaluations were carried out with a group of 26 girls with FXS, and 14 girls without FXS as a control group, using standardized tests. The two groups were homogeneous in age and IQ. Significant differences were found between groups in the relationship between some language processes: inhibition, auditory working memory, cognitive flexibility, level of social adaptation, self-direction, conceptual adaptation, academic skills, leadership ability, theory of mind, and arithmetic. In the group of girls with FXS, it was found that different aspects of language influence some of the executive functions evaluated, in addition to some specific aspects of social perception, adaptive behavior, and quantitative reasoning, in different ways. Future research should incorporate the study of the influence of other cognitive variables such as visual perception and executive function on behavioral, social, and adaptive aspects to know the real influence of all the cognitive variables on the behavior of girls with FXS.

Bullying Victimization in Young Females with Fragile-X-Syndrome

The aim of this study is to investigate the risk associated with girls with fragile X syndrome (FXS) suffering bullying in the role of a victim and its effects on their adaptive behavior, socialization style, and emotional state. A neuropsychological assessment was carried out on a sample of 40 participants (26 FXS positive and 14 control group) using the following instruments: WISC-V, SENA, BAS-2, ABAS-II. The results show that the group of girls with FXS presented higher ratios of lack of social support and isolation from classmates. This finding suggests that problems with social interaction and communication in the group of girls with FXS could lead to difficulties in interpreting social signals and identifying situations of bullying correctly, placing them in a very vulnerable situation.

Understanding attention, memory and social biases in fragile X syndrome: Going below the surface with a multi-method approach

Fragile X syndrome (FXS) is characterised by atypical social behaviours, such as gaze aversion. However, it remains unclear whether, or if so how, these behaviours affect cognitive processing and influence memory. We asked children with FXS (N = 16) and typically developing children (TD; N = 46) to explore naturalistic scenes containing social and non-social salient items unrelated to their task at hand (searching for a simple target object). We also assessed children's memory for target locations. We complemented behavioural responses with eye-tracking data for the subset of participants who managed to comply with calibration and the demands of the experimental testing session (6 children with FXS and 43 TD children). Children with FXS performed well at the experimental task, and showed similar accuracy and speed in locating targets in natural scenes to children of equivalent verbal abilities. They also learned target locations over blocks, but their memory of target locations was not as precise as that of comparison children. In addition, children with FXS initially directed few first looks to salient social items within the scenes, but these looks increased over blocks. Like TD children, children with FXS also dwelled gaze upon social items while recalling target locations from memory. Individual differences in everyday social characteristics also related to gaze and behavioural measures. In conclusion, experimental approaches can highlight cognitive underpinnings of atypical social behaviour in FXS, pinpointing both similarities and differences to TD individuals.

Expressive language sampling as a source of outcome measures for treatment studies in fragile X syndrome: feasibility, practice effects, test-retest reliability, and construct validity

BACKGROUND

The evaluation of treatment efficacy for individuals with fragile X syndrome (FXS) or intellectual disability (ID) more generally has been hampered by the lack of adequate outcome measures. We evaluated expressive language sampling (ELS) as a procedure for generating outcome measures for treatment research in FXS. We addressed: (a) feasibility, (b) practice effects over two administrations, (c) test-retest reliability over the repeated administrations, and (d) construct validity. We addressed these issues for the full sample as well as for subgroups defined by age, IQ, and ASD status.

METHODS

Participants were 106 individuals with FXS between ages 6 and 23 years who had IQs within the range of intellectual disability (IQ < 70). ELS procedures for collecting samples in conversation and narration were followed and analyzed separately. Five measures were derived from transcripts segmented into C-units (i.e., an independent clause and its modifiers): number of C-units per minute (talkativeness), number of different word roots (vocabulary), C-unit length in morphemes (syntax), percentage of C-units containing dysfluency (utterance planning), and percentage of C-units that were fully or partly unintelligible (articulatory quality). ELS procedures were administered twice at 4-week intervals for each participant. Standardized tests and informant reports were administered and provided measures for evaluating construct validity of ELS measures.

RESULTS

We found low rates of noncompliance, suggesting the task can be completed meaningfully by most individuals with FXS, although noncompliance was higher for younger, lower IQ, and more autistic participants. Minimal practice effects and strong test-retest reliability over the 4-week interval were observed for the full sample and across the range of ages, IQs, and autism symptom severity. Evidence of convergent construct validity was observed for the measures of vocabulary, syntax, and unintelligibility for the full sample and across the range of IQ and autism symptom severity, but not for participants under age 12. Conversation and narration yielded largely similar results in all analyses.

CONCLUSIONS

The findings suggest that the ELS procedures are feasible and yield measures with adequate psychometric properties for a majority of 6 to 23 years with FXS who have ID. The procedures work equally well regardless of level of ID or degree of ASD severity. The procedures, however, are more challenging and have somewhat less adequate psychometric properties for individuals with FXS under age 12.

Social and Object Attention Is Influenced by Biological Sex and Toy Gender-Congruence in Children With and Without Autism

Emerging research suggests social attention in autism spectrum disorder (ASD) girls is enhanced relative to ASD boys but may also be affected by the type of social and nonsocial content presented. This study examined how biological sex and gender norms interact to influence visual attention in 79 school-aged children observing scenes that included gender-associated toys and actors of both sexes. Attention to social (faces) and object activity (hands with toys) stimuli was measured. Previously described distinctions between social attention in ASD boys and girls were replicated, with ASD girls looking more at faces than ASD boys. Irrespective of diagnosis, males and females attended more to actors that shared their same sex, and attended more to toys with gender-associations that were consistent with their own sex, suggesting that social and object salience increases for children under sex-consistent conditions. Importantly, ASD and typically developing (TD) children increased their gaze to faces when male actors were shown playing with female-associated toys, suggesting that both groups of children are sensitive to societal messages about the acceptability of males playing with female-associated toys. Our findings provide further evidence of heightened attention to faces in ASD girls relative to ASD boys, and indicate that social attention in ASD and TD children is influenced by who (male or female actor) and what (male- or female-associated toy) is being observed. Collectively, these results present a nuanced profile of attention in ASD that adds to a growing body of research indicating subtle phenotypic differences in ASD girls that may impact identification, assessment, and intervention. Autism Res 2020, 13: 763-776.. © 2019 International Society for Autism Research, Wiley Periodicals, Inc. LAY SUMMARY: Sex differences observed in typical development may also be present in individuals with autism. In this study, we developed an eye-tracking paradigm featuring videos of boys and girls playing with toys that varied in their gender associations. Attention to faces differed between autistic and non-autistic children but was also influenced by the sex of the actor and gender-association of toys. Autistic females demonstrated subtle attention differences that distinguished them from autistic males and may influence referral, diagnosis, and intervention.

Syntactic Ability of Girls With Fragile X Syndrome: Phonological Memory and Discourse Demands on Complex Sentence Use

This study was designed to establish the extent of delay in complex sentence use by females with fragile X syndrome (FXS) and to identify sources of variability among individuals. Females with FXS (n = 16; 10;2-15;7) and younger typically developing girls (n = 17; 4;1-8;11) were group-wise matched on nonverbal cognition and receptive syntax. Language samples (conversation and narration) yielded syntactic complexity in terms of mean length of C-unit (MLCU) and Developmental Level sentence coding (DLevel; Rosenberg & Abbeduto, 1987 ). Complex syntax was not weaker than developmental expectations; however, MLCU was lower than expected for age. Phonological memory and verbal working memory correlated with measures of syntactic complexity in narration. Discourse demands may play an important role in the language produced by females with FXS.

Visual attention to faces in children with autism spectrum disorder: are there sex differences?

Background

The male bias in autism spectrum disorder (ASD) diagnoses is well documented. As a result, less is known about the female ASD phenotype. Recent research suggests that conclusions drawn from predominantly male samples may not accurately capture female behavior. In this study, we explore potential sex differences in attention to social stimuli, which is generally reported to be diminished in ASD. Population-based sex differences in attention to faces have been reported, such that typically developing (TD) females attend more to social stimuli (including faces) from infancy through adulthood than TD males. It is yet unknown whether population-based sex differences in the face domain are preserved in ASD.

Methods

A dynamic, naturalistic infrared eye-tracking paradigm measured attention to social stimuli (faces) in 74 school-aged males and females with ASD (male N = 23; female N = 19) and without ASD (male N = 16; female N = 16). Two kinds of video stimuli were presented that varied in social content: rich social scenes (dyadic play between two children) and lean social scenes (parallel play by two children).

Results

Results revealed a significant 3-way interaction between sex, diagnosis, and condition after controlling for chronological and mental age. ASD females attended more to faces than ASD males in the socially lean condition. This effect was not found in the typically developing (TD) group. ASD males attended less to faces regardless of social context; however, ASD females only attended significantly less to faces compared to TD females in the socially rich condition. TD males and ASD females did not differ in their attention to faces in either condition.

Conclusions

This study has implications for how the field understands core social deficits in children with ASD, which should ideally be benchmarked against same-sex peers (male and female). Social attention in ASD females fell on a continuum—greater than their ASD male peers, but not as great as TD females. Overall, their social attention mirrored that of TD males. Improved understanding of the female social phenotype in ASD will enhance early screening and diagnostic efforts and will guide the development of sex-sensitive experimental paradigms and social interventions.

Optimization of ribosome profiling using low-input brain tissue from fragile X syndrome model mice

Dysregulated protein synthesis is a major underlying cause of many neurodevelopmental diseases including fragile X syndrome. In order to capture subtle but biologically significant differences in translation in these disorders, a robust technique is required. One powerful tool to study translational control is ribosome profiling, which is based on deep sequencing of mRNA fragments protected from ribonuclease (RNase) digestion by ribosomes. However, this approach has been mainly applied to rapidly dividing cells where translation is active and large amounts of starting material are readily available. The application of ribosome profiling to low-input brain tissue where translation is modest and gene expression changes between genotypes are expected to be small has not been carefully evaluated. Using hippocampal tissue from wide type and fragile X mental retardation 1 (Fmr1) knockout mice, we show that variable RNase digestion can lead to significant sample batch effects. We also establish GC content and ribosome footprint length as quality control metrics for RNase digestion. We performed RNase titration experiments for low-input samples to identify optimal conditions for this critical step that is often improperly conducted. Our data reveal that optimal RNase digestion is essential to ensure high quality and reproducibility of ribosome profiling for low-input brain tissue.

Parenting of children with Down syndrome compared to fragile X syndrome

Children with Down syndrome (DS) and fragile X syndrome (FXS) struggle with language development. Parenting variables, such as responsiveness to children's communication attempts (Maternal Responsivity), and techniques used to support and teach appropriate behavior (Behavior Management) are known to have a significant impact on early child development. We examined these two aspects of parenting style via coded, videotaped parent-child interactions in two groups of participants matched on child age (2-5 years) and child expressive language level: mothers of children with DS and mothers of children with FXS. The mothers differed in their use of gestures and redirecting the child's attention. Overall, mothers in both groups of children appeared to adapt appropriately to their children's developmental needs.

Noncomprehension Signaling in Males and Females With Fragile X Syndrome

Purpose

This study used a prospective longitudinal design to evaluate the trajectory and predictors of noncomprehension signaling in male and female youth with fragile X syndrome (FXS).

Method

A direction-following task in which some of the directions were inadequate was administered. Participants were 52 youth (36 boys, 16 girls) with FXS. Upon study entry, participants ranged from 10 to 16 years. The average number of annual assessments per participant was 3.65 (range = 1-4), providing 198 data points for analysis.

Results

Participants with FXS were less likely to signal noncomprehension than younger, typically developing, cognitively matched children. The average rate of change in noncomprehension signaling was not significantly different from 0 for either boys or girls, suggesting a plateau. Both FMRP and nonverbal IQ were significant independent predictors of noncomprehension signaling for boys. Variability in noncomprehension signaling among girls was not explained by any of the predictors, but trends similar to those observed for boys were observed.

Conclusions

Noncomprehension signaling appears to be an area of weakness for individuals with FXS. Because the failure to signal noncomprehension can have negative, cumulative effects on comprehension, the results suggest a need for interventions targeting the requisite cognitive skills.

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.

Prognostic dilemmas and genetic counseling for prenatally detected fragile X gene expansions

With widespread adoption of fragile X carrier screening in pregnant women, the number of expectant couples receiving news of an unanticipated Fragile X Mental Retardation 1 (FMR1) gene expansion has increased. The most common abnormal result from maternal FMR1 testing involves an intermediate allele, also known as a gray zone result, which requires genetic counseling but poses minimal risk for an adverse developmental outcome. By contrast, the finding of a maternal FMR1 premutation or full mutation during pregnancy has important implications for the woman herself, her unborn child, and her extended family. These multiple levels of impact, in addition to the complex inheritance pattern and variable expressivity of fragile X-associated disorders, cause significant stress for newly identified expectant couples and pose unique challenges for genetic counselors in the prenatal setting. © 2016 John Wiley & Sons, Ltd.

Do Children With Fragile X Syndrome Show Declines or Plateaus in Adaptive Behavior?

This study explores if children with fragile X syndrome (FXS) show advances, declines, or plateaus in adaptive behavior over time and the relationship of nonverbal cognitive abilities and autistic behavior on these trajectories. Parents of 55 children with FXS completed the Vineland Adaptive Behavior Scales ( Sparrow, Balla, & Cicchetti, 1984 ; Sparrow, Cicchetti, & Balla, 2005 ) between 3 and 6 times from 2 to 10 years of age. Using raw scores, results indicate that about half of the sample showed advances in adaptive behavior, whereas the other half showed declines, indicating a regression in skills. Children who were more cognitively advanced and had less autistic behaviors had higher trajectories. Understanding the developmental course of adaptive behavior in FXS has implications for educational planning and intervention, especially for those children showing declines.

A comparison of pragmatic language in boys with autism and fragile X syndrome

PURPOSE

Impaired pragmatic language (i.e., language use for social interaction) is a hallmark feature of both autism spectrum disorder (ASD) and fragile X syndrome (FXS), the most common known monogenic disorder associated with ASD. However, few cross-population comparisons of ASD and FXS have been conducted, and it is unclear whether pragmatic language profiles in these conditions overlap.

METHOD

The authors used seminaturalistic and standardized assessment methods to characterize pragmatic language abilities of 29 school-aged boys with idiopathic ASD, 38 with FXS and comorbid ASD, 16 with FXS without ASD, 20 with Down syndrome, and 20 with typical development.

RESULTS

Similar severity of pragmatic language deficits was observed in both of the groups with ASD (idiopathic and fragile X-associated). ASD comorbidity had a detrimental effect on the pragmatic language skills of the boys with FXS. Some different patterns emerged across the two pragmatic assessment tools, with more robust group differences observed in pragmatics assessed in a seminaturalistic conversational context.

CONCLUSION

These findings have implications for pragmatic language assessment and intervention, as well as for understanding the potential role of the fragile X gene, Fragile X Mental Retardation-1, in the pragmatic language phenotype of ASD.

Social cognition in adolescent girls with fragile x syndrome

This study aimed to characterize social cognition, executive functions (EFs), and everyday social functioning in adolescent girls with fragile X syndrome, and identify relationships among these variables. Participants were 20 girls with FXS and 20 age-matched typically developing peers. Results showed significant between-groups differences in social cognition, accounted for by differences in IQ and language. Within the FXS group, IQ and language were related to social cognition; parent-reported social functioning was related to language and EFs; and self-reported social functioning was generally good and not related to cognitive or social cognition variables. Results suggest that intervention might focus on managing language and cognitive contributions to social functioning, rather than social cognition, and underscore the importance of considering parent and adolescent perspectives.

Feasibility, reproducibility, and clinical validity of the pediatric anxiety rating scale-revised for fragile X syndrome

Fragile X syndrome (FXS) is the most common inherited cause of intellectual disability and the most common known genetic cause of autism. FXS is associated with psychiatric impairments, including anxiety disorders. There is a paucity of well-developed measures to characterize anxiety in FXS. However, such scales are needed to measure therapeutic responses to interventions. The Pediatric Anxiety Rating Scale-Revised (PARS-R) was evaluated in 49 individuals with FXS. Feasibility, reproducibility, and clinical validity were assessed. High inter-rater, test-retest, and cross-site reliability were achieved. PARS-R scores were correlated with parent-report and physician ratings of anxiety, suggesting good clinical validity. Results were similar within gender and age subgroups. The PARS-R is a promising tool for measuring the efficacy of interventions targeting anxiety in FXS.

An investigation of narrative ability in boys with autism and fragile X syndrome

Whereas pragmatic language difficulties are characteristic of both autism and Fragile X syndrome, it is unclear whether such deficits are qualitatively similar or whether certain skills are differentially affected. This study compared narrative competence in boys with autism, Fragile X syndrome, Down syndrome, and typical development. Results revealed that an interaction between diagnosis and nonverbal mental age predicted narrative microstructure (e.g., complex syntax) but not macrostructure (e.g., thematic maintenance). Correlations with FMR1-related variation were investigated in children with Fragile X syndrome. While CGG repeat length was associated with many language characteristics, nonverbal IQ appeared to mediate these relationships. These findings are an important step toward understanding narrative abilities in boys with and without the FMR1 mutation.

Hyper-reactivity in fragile X syndrome females: generalised or specific to socially-salient stimuli? A skin conductance study

Fragile X syndrome (FXS) is characterised by hyper-reactivity, autistic tendencies and social anxiety. It has been hypothesised that the FXS social phenotype is secondary to a generalised hyper-reactivity that leads to social avoidance. No study, however, has investigated whether hyperarousal in FXS is generalised or more specific to socially salient information. We recorded skin conductance responses (SCRs) while females with FXS, as well as chronological age-(CA-) and mental age-(MA-) matched controls, viewed two sets of visual images: direct-gaze emotional faces and affectively arousing scenes. Explicit emotion recognition and subjective ratings of emotions aroused by images were also recorded. Overall, females with FXS displayed hyper-reactivity only when viewing the more socially salient stimuli (emotional faces), compared to CA-matched controls, but not MA-matched controls. Moreover, females with FXS also displayed atypical emotion recognition abilities and subjective ratings of their own emotional states. These findings suggest that any hyper-reactivity observed in FXS may be more specific to socially salient stimuli, rather than generalised.

Fear-specific amygdala function in children and adolescents on the fragile x spectrum: a dosage response of the FMR1 gene

Mutations of the fragile X mental retardation 1 (FMR1) gene are the genetic cause of fragile X syndrome (FXS). The presence of significant socioemotional problems has been well documented in FXS although the brain basis of those deficits remains unspecified. Here, we investigated amygdala dysfunction and its relation to socioemotional deficits and FMR1 gene expression in children and adolescents on the FX spectrum (i.e., individuals whose trinucleotide CGG repeat expansion from 55 to over 200 places them somewhere within the fragile X diagnostic range from premutation to full mutation). Participants performed an fMRI task in which they viewed fearful, happy, and scrambled faces. Neuroimaging results demonstrated that FX participants revealed significantly attenuated amygdala activation in Fearful > Scrambled and Fearful > Happy contrasts compared with their neurotypical counterparts, while showing no differences in amygdala volume. Furthermore, we found significant relationships between FMR1 gene expression, anxiety/social dysfunction scores, and reduced amygdala activation in the FX group. In conclusion, we report novel evidence regarding a dosage response of the FMR1 gene on fear-specific functions of the amygdala, which is associated with socioemotional deficits in FXS.

Language development in school-age girls with fragile X syndrome

BACKGROUND

Girls with fragile X syndrome (FXS) have a wide range of cognitive and language abilities. The range of language outcomes experienced by girls with FXS, however, has been relatively unexplored. The purpose of this exploratory study was to examine receptive and expressive language, with a focus on vocabulary and syntax, in a group of school-age girls with FXS.

METHOD

Twenty-one girls with FXS aged 7-15 years participated in the study. The girls completed a receptive vocabulary test, non-verbal IQ test and an expressive language sample.

RESULTS

The mean IQ for this group of girls was at the cut-off for intellectual disability. Vocabulary was an area of strength relative to non-verbal cognition. Age and non-verbal IQ were significant predictors of vocabulary performance.

CONCLUSIONS

The data suggest that a substantial portion of the sample would qualify for speech and language services. This study highlights the need for continued research in the area of language and cognitive development in girls with the full mutation of fragile X.

Gene, brain, and behavior relationships in fragile X syndrome: evidence from neuroimaging studies

Fragile X syndrome (FraX) remains the most common inherited cause of intellectual disability and provides a valuable model for studying gene-brain-behavior relationships. Over the past 15 years, structural and functional magnetic resonance imaging studies have emerged with the goal of better understanding the neural pathways contributing to the cognitive and behavioral outcomes seen in individuals with FraX. Specifically, structural MRI studies have established and begun to refine the specific topography of neuroanatomical variation associated with FraX. In addition, functional neuroimaging studies have begun to elucidate the neural underpinnings of many of the unique characteristics of FraX including difficulties with eye gaze, executive functioning, and behavioral inhibition. This review highlights studies with a focus on the relevant gene-brain-behavior connections observed in FraX. The relationship of brain regions and activation patterns to FMRP are discussed as well as the clinical cognitive and behavioral correlates of these neuroimaging findings.

Expressive language in male adolescents with fragile X syndrome with and without comorbid autism

BACKGROUND

Approximately one-quarter of individuals with fragile X syndrome (FXS) meet diagnostic criteria for autism; however, it is unclear whether individuals with comorbid FXS and autism are simply more severely affected than their peers with only FXS or whether they have qualitatively different profiles of behavioural impairments. To address this issue, variation in the FXS linguistic phenotype was examined in males with FXS with and without autism. The syndrome-specificity of the expressive language impairment of both groups of those with FXS was assessed in relation to Down syndrome. The extent to which different language sampling contexts affected expressive language in each diagnostic group was also examined.

METHOD

Spontaneous language samples were collected from male adolescents with FXS without autism (n = 20), comorbid FXS and autism (n = 8), and Down syndrome (n = 16). Syntactic complexity (indexed by mean length of utterance), expressive vocabulary (indexed by lexical diversity), talkativeness, fluency and intelligibility were assessed in two contexts: conversation and narration. Groups were matched on non-verbal IQ, non-verbal mental age and chronological age to allow the assessment of relative strengths and weaknesses across language variables.

RESULTS

Males with comorbid FXS and autism were less intelligible than males with only FXS; no other differences between these two groups were found. Participants' performance differed across contexts for syntactic complexity, lexical diversity, talkativeness and fluency.

CONCLUSIONS

These findings contribute to existing research on the behavioural profiles of individuals with FXS or FXS with autism who have low cognitive abilities. Although individuals with comorbid FXS and autism may be, as a group, more impaired than those with only FXS, data from this small sample of males with comorbid FXS and autism with low IQs suggest that their relative strengths and weaknesses in spontaneous expressive language are largely comparable and not differentially affected by the context in which their talk occurs.

Developmental trajectories of young girls with fragile x syndrome

To describe the early phenotype of girls with full mutation fragile X, we used 54 observations of 15 girls between the ages of 6 months and 9 years to examine developmental trajectories as measured by the Battelle Development Inventory. In this sample, autistic behavior was associated with poorer developmental outcomes, primarily due to interactions of age with autistic behavior, even though autistic behavior, measured continuously, was relatively mild. Although this small sample, ascertained primarily through male relatives with fragile X syndrome, limits generalizability, considerable variability in developmental outcome in young girls was documented. In addition, findings support previous research suggesting that even mild autistic behaviors in girls can be associated with developmental outcomes.

Language Development in Individuals with Fragile X Syndrome

Fragile X syndrome (FXS) is the leading inherited cause of intellectual disability. The syndrome is caused by a single gene mutation on the X chromosome. Although individual differences are large, most individuals with FXS display weaknesses across all language and literacy domains compared to peers of the same chronological age with typical cognitive and language development. Expressive, receptive, and pragmatic language abilities as well as literacy skills are similar to those of younger, typically developing peers at similar cognitive and language developmental levels, although there are areas in which impairments exceed developmental-level expectations. One area of special impairment is the higher occurrence of repetition in the language of individuals with FXS compared to developmentally matched peers. In this paper, we review the behavioral, language, and literacy characteristics of individuals with FXS and discuss potential clinical implications.

Mood and anxiety disorders in females with the FMR1 premutation

Fragile X syndrome (FXS) is a model for studying the relative contributions of genetic and environmental factors to psychiatric disorders in mothers of children with disabilities. Here, we examine the frequency and predictors of mood and anxiety disorders in mothers with the FMR1 premutation. Ninety-three females with the FMR1 premutation were in the study and were compared to 2,159 women from the National Comorbidity Survey Replication (NCS-R) dataset. Mood and anxiety disorders were assessed using the SCID-I. Our data reflect elevated lifetime major depressive disorder (MDD), lifetime panic disorder without agoraphobia and current agoraphobia without panic disorder in the FMR1 premutation sample. Also, we found a low frequency of lifetime social phobia, specific phobia, and post-traumatic stress disorders and current specific phobia in the FMR1 premutation sample. The profile of MDD in the FMR1 premutation sample was not episodic or comorbid with an anxiety disorder, as in the NCS-R dataset. Never having been married and smaller CGG repeat length were associated with increased likelihood of MDD while increased children with FXS in the family and greater child problem behaviors were associated with increased likelihood of an anxiety disorder in the FMR 1 premutation group. Major depression in females with the FMR1 premutation may not be characterized as an episodically chronic recurrent disorder as it is in community samples and may have a genetic basis given the relationship with CGG repeat length and lack of association with all child and most demographic factors.

Aberrant neural function during emotion attribution in female subjects with fragile X syndrome

OBJECTIVE

Fragile X (FraX) syndrome is caused by mutations of the FraX mental retardation-1 gene-a gene responsible for producing FraX mental retardation protein. The neurocognitive phenotype associated with FraX in female subjects includes increased risk for emotional disorders including social anxiety, depression, and attention deficit. Here, the authors investigated the neurobiological systems underlying emotion attribution in female subjects with FraX syndrome.

METHOD

While undergoing functional magnetic resonance imaging, 10 high-functioning female subjects with FraX syndrome and 10 typically developing (TD) female subjects were presented with photographs of happy, sad, and neutral faces and instructed to determine the facial emotion.

RESULTS

No significant group differences were found for the recognition of happy faces, although the FraX group showed a trend toward a significant difference for the recognition of sad faces and significantly poorer recognition of neutral faces. Controlling for between-group differences in IQ and performance accuracy, the TD group had greater activation than the FraX group in the anterior cingulate cortex (ACC) for neutral faces compared with scrambled faces and the caudate for sad faces compared with scrambled faces (but not for sad faces compared with neutral faces). In the FraX group, FraX mental retardation protein levels positively correlated with activation in the dorsal ACC for neutral, happy, and sad faces when independently compared with scrambled faces. Significantly greater negative correlation between IQ and insula activation for neutral faces relative to scrambled faces was observed in the FraX group compared with the TD group. Significantly greater positive correlation between IQ and ACC activation for neutral faces relative to scrambled faces was observed in the TD group compared with the FraX group.

CONCLUSIONS

Although emotion recognition is generally spared in FraX syndrome, the emotion circuit (i.e., ACC, caudate, insula) that modulates emotional responses to facial stimuli may be disrupted.

Rote numeric skills may mask underlying mathematical disabilities in girls with fragile x syndrome

Mathematical learning disabilities (MLD) have been reported for elementary school age girls with fragile X syndrome who do not have mental retardation. Yet girls with fragile X demonstrate age-appropriate rote math skills, sometimes outperforming other children with MLD. We examined whether MLD and strengths in rote math skills persist during middle school among girls with fragile X. Middle school children were individually administered the Ranking Proportions Task (RPT), which involves fractions and decimals. Such problems, although difficult for many students, yield different performance profiles between children with versus without MLD. We hypothesized that girls with fragile X would outperform children with MLD on rote skills (e.g., naming decimals) despite conceptual difficulties, regardless of effects of FSIQ. To address the influence of fragile X versus MLD or FSIQ, several comparison groups were included. Children from a normative sample outperformed girls with fragile X on conceptual, but not rote, skills. However, their performance resembled that of children with MLD on conceptual skills, such as identifying equal quantities with different symbols (e.g., 0.5 and 1/2). Fragile X syndrome provides a compelling model of the heterogeneity of MLD, as the associated profile resembles that of both children with or without MLD. In terms of applications to serving girls with fragile X, it is important to consider that efficient rote skills may not only fail to enhance math achievement, they may hinder achievement by masking underlying conceptual deficiencies.

Language development in Down syndrome: from the prelinguistic period to the acquisition of literacy

Down syndrome (DS) is associated with abnormalities in multiple organ systems and a characteristic phenotype that includes numerous behavioral features. Language, however, is among the most impaired domains of functioning in DS and, perhaps, also the greatest barrier to independent meaningful inclusion in the community. In this article, we review what is known about the extent, nature, and correlates of the language and related problems of individuals with Down syndrome. In doing so, we focus largely on the syndrome-specific features of the language phenotype, although we also consider within-syndrome variation. The review focuses on the prelinguistic foundations of language and the major components of language (i.e., vocabulary, syntax, and pragmatics). We also consider two topics in the treatment and education of individuals with DS: prelinguistic communication intervention and the acquisition of literacy skills.

Syntactic complexity during conversation of boys with fragile X syndrome and Down syndrome

PURPOSE

This study compared the syntax of boys who have fragile X syndrome (FXS) with and without autism spectrum disorder (ASD) with that of (a) boys who have Down syndrome (DS) and (b) typically developing (TD) boys.

METHOD

Thirty-five boys with FXS only, 36 boys with FXS with ASD, 31 boys with DS, and 46 TD boys participated. Conversational language samples were evaluated for utterance length and syntactic complexity (i.e., Index of Productive Syntax; H. S. Scarborough, 1990).

RESULTS

After controlling for nonverbal mental age and maternal education levels, the 2 FXS groups did not differ in utterance length or syntactic complexity. The FXS groups and the DS group produced shorter, less complex utterances overall and less complex noun phrases, verb phrases, and sentence structures than did the TD boys. The FXS with ASD group and the DS group, but not the FXS-only group, produced less complex questions/negations than did the TD group. Compared with the DS group, both FXS groups produced longer, more complex utterances overall, but on the specific complexity measures, they scored higher only on questions/negations.

CONCLUSION

Boys with FXS and DS have distinctive language profiles. Although both groups demonstrated syntactic delays, boys with DS showed greater delays.

Arousal modulation in females with fragile X or Turner syndrome

The present study was carried out to examine physiological arousal modulation (heart activity and skin conductance, across baseline and cognitive tasks, in females with fragile X or Turner syndrome and a comparison group of females with neither syndrome. Relative to the comparison group, for whom a greater increase in skin conductance was associated with poor arithmetic performance and less risk taking behavior, females with fragile X displayed a minimal increase in heart activity that was nevertheless associated with poor performance on mental arithmetic. In contrast, no arousal-cognitive performance relationship emerged for the group with Turner syndrome. Taken together, our findings suggest that distinct profiles of arousal modulation might be associated with cognitive deficits in these syndrome populations.

Language development and fragile X syndrome: profiles, syndrome-specificity, and within-syndrome differences

Fragile X syndrome (FXS) is the leading inherited cause of mental retardation. In this article, we review what is known about the language and related problems of individuals with FXS. In doing so, we focus on the syndrome-specific features of the language phenotype and on the organismic (i.e., genetic and individual neurocognitive and behavioral) and environmental factors associated with within-syndrome variation in the phenotype. We also briefly review those aspects of the behavioral phenotype of FXS that are relevant for understanding syndrome-specific features of, and within-syndrome variability in, language. The review includes summaries of research on the prelinguistic foundations for language development and on each of the major components of language (i.e., vocabulary, morphosyntax, and pragmatics). Throughout the review, we point out implications of existing research for intervention as well as directions for future research.

Communication in young children with fragile X syndrome: a qualitative study of mothers' perspectives

PURPOSE

To provide descriptive and qualitative information about communication in young children with fragile X syndrome (FXS) and about how families react to and accommodate communication differences in their children.

METHOD

In-depth interviews were conducted with 55 mothers of young children with FXS. Interviewers asked mothers to describe their children's communication, strategies they used to help promote their children's communication, communication-related frustrations, their expectations for their children, and the roles that they perceive for themselves.

RESULTS

Over half the children were nonverbal and learning to communicate with augmentative and alternative communication. Mothers reported using strategies that were developmentally appropriate and recommended by early childhood experts, such as reading and talking to their children. Many mothers identified challenges faced in helping their child to communicate, and some cited difficulty obtaining speech-language services as a challenge. Mothers identified their roles as caregiver, teacher, therapist, and advocate.

CONCLUSIONS

The perspectives offered by mothers are valuable because they indicate how children with FXS communicate in natural contexts. Information about mothers' expectations and roles may help clinicians to be sensitive to variables that will affect working with young children and their families.

Genetic counseling for fragile x syndrome: updated recommendations of the national society of genetic counselors

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

Assessing Executive Dysfunction in Girls With Fragile X or Turner Syndrome Using the Contingency Naming Test (CNT)

The aim of this study was to examine executive function (EF) skills in girls with fragile X or Turner syndrome, using the Contingency Naming Test (CNT). The CNT is a Stroop-like task involving a 1- or 2-attribute contingency rule. We predicted that girls with fragile X would make errors reflecting poor cognitive flexibility and working memory limitations. We predicted that girls with Turner syndrome would have sufficient cognitive flexibility to perform the CNT accurately, but would have difficulty with verbal inhibition and would thus make more self-corrections than girls in a comparison group. The hypotheses were partially supported: relative to their Full Scale IQ-matched comparison group, girls with fragile X or Turner syndrome were slower on the warm-up naming task; girls with fragile X made more errors on the 1-attribute task, and girls with Turner syndrome were less efficient on both the 1- and 2-attribute tasks, without making more self-corrections. These results support previous findings of executive dysfunction associated with fragile X or Turner syndrome. The results suggest that both low IQ and fragile X status contribute to working memory limitations in girls with fragile X and that EF inefficiency in girls with Turner syndrome is due to both working memory limitations and slower response times.

Mapping nonverbal IQ in young boys with fragile X syndrome

This study examines the developmental changes in nonverbal intellectual functioning evident in males with fragile X syndrome (FXS) measured by the Leiter International Performance Scales-Revised (Leiter-R). The Leiter-R provides both IQ scores and associated growth scores which permit the examination of both age-based IQ scores and overall intellectual growth. Participants were 45 males with full mutation FXS and ranged in age from 4.0 to 13.8 years. Each child was assessed annually using the Leiter-R as part of a larger longitudinal battery for an average of 3.5 assessments per child and a range of 2-6 assessments, representing a total of 156 assessment occasions. Longitudinal analyzes of Leiter scores consisted primarily of hierarchical linear modeling, with the impact of chronological age, maternal education, fragile X mental retardation 1 protein (FMRP), autistic behaviors also being assessed. Findings revealed a significant linear decline in nonverbal IQ scores, with no effects of maternal education, autistic behaviors, or FMRP on mean level or rate of change in IQ scores over time. The decline slowed significantly around 8 years of age, but scores continued to decline into the 12th year of age. In contrast, a significant linear increase was observed in Leiter-R growth scores, which was negatively influenced by autistic behaviors. The rate of increase did not change over time, and neither mean level nor rate of increase was influenced by maternal education or FMRP levels. These findings suggest that declines in IQ are the result of steady, but suboptimal intellectual growth, rather than a true deterioration in overall intellectual functioning.

The emerging fragile X premutation phenotype: Evidence from the domain of social cognition

Fragile X syndrome is a neurodevelopmental disorder that is caused by large methylated expansions of a CGG repeat (>200) region upstream of the FMR1 gene that results in the lack of expression of the fragile X mental retardation protein (FMRP). Affected individuals display a neurobehavioral phenotype that includes a significant impairment in social cognition alongside deficits in attentional control, inhibition and working memory. In contrast, relatively little is known about the trajectory and specificity of any cognitive impairment associated with the fragile X premutation ("carrier-status") (approximately 55-200 repeats). Here, we focus on one aspect of cognition that has been well documented in the fragile X full mutation, namely social cognition. The results suggest that premutation males display a pattern of deficit similar in profile, albeit milder in presentation, to that of the full mutation. However, little evidence emerged for a correlation between CGG repeat length and severity of phenotypic outcomes. The findings are discussed in the context of functional neuroimaging and brain-behaviour-molecular correlates. We speculate that the deficiencies in social cognition are attributable to impairment of neural pathways modulated by the cerebellum.