Social cognition skills among females with fragile X

Empathy and Anxiety in Young Girls with Fragile X Syndrome

We tested whether empathy is impaired and associated with anxiety in girls with fragile X syndrome (FXS). We measured parent-reported empathy and self-reported anxiety in young girls with FXS and in a developmentally-matched comparison group. Girls with FXS received higher parent-reported scores on cognitive and affective empathy but also self-reported more severe anxiety symptoms, particularly separation anxiety and phobia symptoms, than girls in the comparison group. Girls with FXS who received higher cognitive empathy scores, however, appeared buffered against risk for separation anxiety and phobia symptoms. Girls with FXS experience elevated empathy and anxiety relative to their developmentally-matched peers. Higher cognitive empathy in girls with FXS may indicate resilience against specific forms of anxiety that are commonly observed in FXS.

Neuroanatomical abnormalities in fragile X syndrome during the adolescent and young adult years

Abnormal brain development and cognitive dysfunction have been reported both in children and in adults with fragile X syndrome (FXS). However, few studies have examined neuroanatomical abnormalities in FXS during adolescence. In this study we focus on adolescent subjects with FXS (N = 54) as compared to age- and sex-matched subjects with idiopathic intellectual disability (Comparison Group) (N = 32), to examine neuroanatomical differences during this developmental period. Brain structure was assessed with voxel-based morphometry and independent groups t-test in SPM8 software. Results showed that the FXS group, relative to the comparison group, had significantly larger gray matter volume (GMV) in only one region: the bilateral caudate nucleus, but have smaller GMV in several regions including bilateral medial frontal, pregenual cingulate, gyrus rectus, insula, and superior temporal gyrus. Group differences also were noted in white matter regions. Within the FXS group, lower FMRP levels were associated with less GMV in several regions including cerebellum and gyrus rectus, and less white matter volume (WMV) in pregenual cingulate, middle frontal gyrus, and other regions. Lower full scale IQ within the FXS group was associated with larger right caudate nucleus GMV. In conclusion, adolescents and young adults with FXS demonstrate neuroanatomical abnormalities consistent with those previously reported in children and adults with FXS. These brain variations likely result from reduced FMRP during early neurodevelopment and mediate downstream deleterious effects on cognitive function.

Of Men and Mice: Modeling the Fragile X Syndrome

The Fragile X Syndrome (FXS) is one of the most common forms of inherited intellectual disability in all human societies. Caused by the transcriptional silencing of a single gene, the fragile x mental retardation gene FMR1, FXS is characterized by a variety of symptoms, which range from mental disabilities to autism and epilepsy. More than 20 years ago, a first animal model was described, the Fmr1 knock-out mouse. Several other models have been developed since then, including conditional knock-out mice, knock-out rats, a zebrafish and a drosophila model. Using these model systems, various targets for potential pharmaceutical treatments have been identified and many treatments have been shown to be efficient in preclinical studies. However, all attempts to turn these findings into a therapy for patients have failed thus far. In this review, I will discuss underlying difficulties and address potential alternatives for our future research.

Overview of Social Cognitive Dysfunctions in Rare Developmental Syndromes With Psychiatric Phenotype

Rare neurodevelopmental syndromes often present social cognitive deficits that may underlie difficulties in social interactions and increase the risk of psychosis or autism spectrum disorders. However, little is known regarding the specificities of social cognitive impairment across syndromes while it remains a major challenge for the care. Our review provides an overview of social cognitive dysfunctions in rare diseases associated with psychiatric symptoms (with a prevalence estimated between 1 in 1,200 and 1 in 25,000 live births: 22q11.2 deletion syndrome, Angelman syndrome, Fragile X syndrome, Klinefelter syndrome, Prader-Willi syndrome, Rett syndrome, Smith-Magenis syndrome, Turner syndrome, and Williams syndrome) and shed some light on the specific mechanisms that may underlie these skills in each clinical presentation. We first detail the different processes included in the generic expression "social cognition" before summarizing the genotype, psychiatric phenotype, and non-social cognitive profile in each syndrome. Then, we offer a systematic review of the social cognitive abilities and the disturbed mechanisms they are likely associated with. We followed the PRISMA process, including the definition of the relevant search terms, the selection of studies based on clear inclusion, and exclusion criteria and the quality appraisal of papers. We finally provide insights that may have considerable influence on the development of adapted therapeutic interventions such as social cognitive training (SCT) therapies specifically designed to target the psychiatric phenotype. The results of this review suggest that social cognition impairments share some similarities across syndromes. We propose that social cognitive impairments are strongly involved in behavioral symptoms regardless of the overall cognitive level measured by intelligence quotient. Better understanding the mechanisms underlying impaired social cognition may lead to adapt therapeutic interventions. The studies targeting social cognition processes offer new thoughts about the development of specific cognitive training programs, as they highlight the importance of connecting neurocognitive and SCT techniques.

Joint Attention and Early Social Developmental Cascades in Neurogenetic Disorders

This review examines what is known about joint attention and early social development in three neurogenetic syndromes: Down syndrome, Williams syndrome, and fragile X syndrome. In addition, the potential cascading effects of joint attention on subsequent social development, especially social interaction and social cognition are proposed. The potential issues and complexities associated with conducting prospective, longitudinal studies of infant social development in neurogenetic disorders are discussed.

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.

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.

Social approach and emotion recognition in fragile X syndrome

Evidence is emerging that individuals with Fragile X syndrome (FXS) display emotion recognition deficits, which may contribute to their significant social difficulties. The current study investigated the emotion recognition abilities, and social approachability judgments, of FXS individuals when processing emotional stimuli. Relative to chronological age- (CA-) and mental age- (MA-) matched controls, the FXS group performed significantly more poorly on the emotion recognition tasks, and displayed a bias towards detecting negative emotions. Moreover, after controlling for emotion recognition deficits, the FXS group displayed significantly reduced ratings of social approachability. These findings suggest that a social anxiety pattern, rather than poor socioemotional processing, may best explain the social avoidance observed in FXS.

Emotion recognition and visual-scan paths in Fragile X syndrome

This study investigated emotion recognition abilities and visual scanning of emotional faces in 16 Fragile X syndrome (FXS) individuals compared to 16 chronological-age and 16 mental-age matched controls. The relationships between emotion recognition, visual scan-paths and symptoms of social anxiety, schizotypy and autism were also explored. Results indicated that, compared to both control groups, the FXS group displayed specific emotion recognition deficits for angry and neutral (but not happy or fearful) facial expressions. Despite these evident emotion recognition deficits, the visual scanning of emotional faces was found to be at developmentally appropriate levels in the FXS group. Significant relationships were also observed between visual scan-paths, emotion recognition performance and symptomology in the FXS group.

Outcome measures for clinical trials in fragile X syndrome

OBJECTIVE

Progress in basic neuroscience has led to identification of molecular targets for treatment in fragile X syndrome (FXS) and other neurodevelopmental disorders; however, there is a gap in translation to targeted therapies in humans. One major obstacle to the demonstration of efficacy in human trials has been the lack of generally accepted endpoints to assess improvement in function in individuals with FXS. To address this problem, the National Institutes of Health convened a meeting of leading scientists and clinicians with the goal of identifying and standardizing outcome measures for use as potential endpoints in clinical trials in FXS.

METHODS

Participants in the meeting included FXS experts, experts in the design and implementation of clinical trials and measure development, and representatives from advocacy groups, industry, and federal agencies.

RESULTS

The group generated recommendations for optimal outcome measures in cognitive, behavioral, and biomarker/medical domains, including additional testing and validation of existing measures and development of new measures in areas of need. Although no one endpoint or set of endpoints could be identified that met all criteria as an optimal measure, recommendations are presented in this report.

CONCLUSION

The report is expected to guide the selection of measures in clinical trials and lead to the use of a more consistent battery of measures across trials. Furthermore, this will help to direct research toward gaps in the development of validated FXS-specific outcome measures and to assist with interpretation of clinical trial data by creating templates for measurement of treatment efficacy.

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.

Social communication and theory of mind in boys with autism and fragile x syndrome

Impairments in the social use of language, or pragmatics, constitute a core characteristic of autism. Problems with pragmatic language have also been documented in fragile X syndrome (FXS), a monogenic condition that is the most common known genetic cause of autism. Evidence suggests that social cognitive ability, or theory of mind, may also be impaired in both conditions, and in autism, may importantly relate to pragmatic language ability. Given the substantial overlap observed in autism and FXS, this study aimed to better define those social-communicative phenotypes that overlap in these two conditions by comparing pragmatic language ability and theory of mind in children with idiopathic autism and children with FXS, with and without autism, as well as children with Down syndrome and typically developing controls. We further examined correlations between these cognitive-behavioral phenotypes and molecular genetic variation related to the Fragile X Mental Retardation-1 gene (FMR1) in the FXS group. Results indicated that children with idiopathic autism and those with FXS and autism performed comparably on direct-assessment measures of pragmatic language and theory of mind, whereas those with FXS only did not differ from controls. Theory of mind was related to pragmatic language ability in all groups. Pragmatic language and theory of mind also correlated with genetic variation at the FMR1 locus (Cytosine-Guanine-Guanine repeats and percent methylation). These results point toward substantial overlap in the social and language phenotypes in autism and FXS and suggest a molecular genetic basis to these phenotypic profiles.

Reward circuitry dysfunction in psychiatric and neurodevelopmental disorders and genetic syndromes: animal models and clinical findings

This review summarizes evidence of dysregulated reward circuitry function in a range of neurodevelopmental and psychiatric disorders and genetic syndromes. First, the contribution of identifying a core mechanistic process across disparate disorders to disease classification is discussed, followed by a review of the neurobiology of reward circuitry. We next consider preclinical animal models and clinical evidence of reward-pathway dysfunction in a range of disorders, including psychiatric disorders (i.e., substance-use disorders, affective disorders, eating disorders, and obsessive compulsive disorders), neurodevelopmental disorders (i.e., schizophrenia, attention-deficit/hyperactivity disorder, autism spectrum disorders, Tourette's syndrome, conduct disorder/oppositional defiant disorder), and genetic syndromes (i.e., Fragile X syndrome, Prader-Willi syndrome, Williams syndrome, Angelman syndrome, and Rett syndrome). We also provide brief overviews of effective psychopharmacologic agents that have an effect on the dopamine system in these disorders. This review concludes with methodological considerations for future research designed to more clearly probe reward-circuitry dysfunction, with the ultimate goal of improved intervention strategies.

Comprehensive neurocognitive endophenotyping strategies for mouse models of genetic disorders

There is a need for refinement of the current behavioral phenotyping methods for mouse models of genetic disorders. The current approach is to perform a behavioral screen using standardized tasks to define a broad phenotype of the model. This phenotype is then compared to what is known concerning the disorder being modeled. The weakness inherent in this approach is twofold: First, the tasks that make up these standard behavioral screens do not model specific behaviors associated with a given genetic mutation but rather phenotypes affected in various genetic disorders; secondly, these behavioral tasks are insufficiently sensitive to identify subtle phenotypes. An alternate phenotyping strategy is to determine the core behavioral phenotypes of the genetic disorder being studied and develop behavioral tasks to evaluate specific hypotheses concerning the behavioral consequences of the genetic mutation. This approach emphasizes direct comparisons between the mouse and human that facilitate the development of neurobehavioral biomarkers or quantitative outcome measures for studies of genetic disorders across species.

Brain morphology in autism and fragile X syndrome correlates with social IQ: first report from the Canadian-Swiss-Egyptian Neurodevelopmental Study

Fragile X syndrome shares most of the behavioral phenotypic similarities with autism. How are these similarities reflected in brain morphology? A total of 10 children with autism and 7 with fragile X underwent morphological (T1) 1.5-T magnetic resonance imaging (MRI). The authors found no significant difference in total brain volumes, regional volumes, gyrification index, sulcul depth, and cerebral cortical thickness. However, children with autism showed significant decrease in the medial prefrontal bilaterally and the left anterior cingulate cortices. Regression analysis revealed positive correlation between the medial prefrontal cortical thickness and the social IQ. The authors suggest that the difference between the 2 groups in the medial prefrontal and anterior cingulate cortices thickness may entail an altered social cognitive style. Functional MRI studies directly differentiating between social indifference (autism) and social avoidance (fragile X) are needed to further characterize the spectrum of social abnormalities between these 2 groups.

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.

Psychiatric phenotypes associated with neurogenetic disorders

Advances in understanding the human genome and clinical application have led to identification of genetically based disorders that have distinctive behavioral phenotypes and risk for serious psychiatric disorders. Some patients have unrecognized genetic disorders presenting as psychiatric symptoms. Practitioners must be knowledgeable about the association between symptoms and underlying genetic bases. Treatment of neurogenetic disorders includes providing information about causes and prognoses. Patients are served best if they remain long term with a multidisciplinary team of providers who recognize the realities of a lifetime course, the high risk for symptom recurrence, and the need for providing information and support to families and coordinating medical and psychiatric care.

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.

Facial emotion recognition in intellectual disabilities

PURPOSE OF REVIEW

Interpreting facial emotion is a requisite skill that enables us to navigate our social environment. Autism spectrum disorder is characterized by shortcomings in socio-cognitive abilities in general, and in emotion recognition in particular, and much has been written on this subject. Less research, however, has been conducted on individuals with intellectual disabilities. This review discusses recent emotion recognition research in this population.

RECENT FINDINGS

Facial emotion recognition research in individuals with intellectual disabilities can be divided into two broad categories: studies on the causes of emotion recognition deficits (i.e. primary deficits or secondary phenomena) and studies on the effects of emotion recognition deficits (behavioral implications). Recent research on causes has not yet produced definitive conclusions and current research on specific effects has been limited to aggression and self-reported anger.

SUMMARY

Some evidence exists that individuals with intellectual disability of heterogeneous etiology (excluding autism) have facial affect recognition deficits that cannot be fully accounted for by cognitive-intellectual abilities. In addition, cognitive processing strategies and genetic syndrome-specific differences in facial affect recognition have been discovered but further research is needed. We found no evidence that emotion recognition deficits contribute to the emergence of later antisocial behavior.

Social phenotypes in neurogenetic syndromes

Many of the known genetically based neurodevelopmental disorders are associated with a distinctive behavioral phenotype. As these behavioral phenotypes have been elucidated by clinical research, distinctive profiles of social traits have emerged as prominent syndromic features. This article reviews social phenotypic findings for fragile X syndrome, Down syndrome, Prader-Willi syndrome, Smith-Magenis syndrome, Turner syndrome, Williams syndrome, and velocardiofacial syndrome. An analysis of these social profiles raises several questions regarding the relationship between identified social impairments and autism and the relationship between social impairments in neurodevelopmental disorders and those found in normative child populations. The unique profile of certain of the known behavioral phenotypes also serves to distinguish several dimensions of sociability that are not readily observed in typical populations.

Understanding of facial expressions of emotion by children with intellectual disabilities of differing aetiology

BACKGROUND

Interpreting emotional expressions is a socio-cognitive skill central to interpersonal interaction. Poor emotion recognition has been reported in autism but is less well understood in other kinds of intellectual disabilities (ID), with procedural differences making comparisons across studies and syndromes difficult. This study aimed to compare directly facial emotion recognition skills in children with fragile X syndrome (FXS), Down's syndrome (DS) and non-specific intellectual disability (NSID), contrasting ability and error profiles with those of typically developing (TD) children of equivalent cognitive and linguistic status.

METHODS

Sixty children participated in the study: 15 FXS, 15 DS, 15 NSID and 15 TD children. Standardised measures of cognitive, language and socialisation skills were collected for all children, along with measures of performance on two photo-matching tasks: an 'identity-matching' task (to control for basic face-processing ability) and an 'emotion-matching' task (happiness, sadness, anger, surprise, fear or disgust).

RESULTS

Identity-matching ability did not differ across the four child groups. Only the DS group performed significantly more poorly on the emotion-matching task and only in comparison to the TD group, with fear recognition an area of particular difficulty.

CONCLUSION

Findings support previous evidence of emotion recognition abilities commensurate with overall developmental level in children with FXS or NSID, but not DS. They also suggest, however, that syndrome-specific difficulties may be subtle and detectable, at least in smaller-scale studies, only in comparison with TD matches, and not always across syndromes. Implications for behavioural phenotype theory, educational interventions and future research are discussed.

Ocular motor indicators of executive dysfunction in fragile X and Turner syndromes

Fragile X and Turner syndromes are two X-chromosome-related disorders associated with executive function and visual spatial deficits. In the present study, we used ocular motor paradigms to examine evidence that disruption to different neurological pathways underlies these deficits. We tested 17 females with fragile X, 19 females with Turner syndrome, and 40 females with neither disorder who comprised the comparison group. Group differences emerged for both the fragile X and Turner syndrome groups, each relative to the comparison group: Females with fragile X had deficits in generating memory-guided saccades, predictive saccades, and saccades made in the overlap condition of a gap/overlap task. Females with Turner syndrome showed deficits in generating memory-guided saccades, but not during either the predictive saccade or gap/overlap task. Females with Turner syndrome, but not females with fragile X, showed deficits in visually guided saccades and anti-saccades. These findings indicate that different brain regions are affected in the two disorders, and suggest that different pathways lead to the similar cognitive phenotypes described for fragile X and Turner syndromes.

Is Theory of Mind Understanding Impaired in Males with Fragile X Syndrome?

Males with fragile X syndrome (FXS) have difficulties with social interaction and many show autistic features. This study examined whether the social deficits characteristic of FXS are associated with theory of mind difficulties. Two groups of boys with FXS participated: a group with few autistic features and a group with many autistic features. An intellectual disability control group also participated. In addition to using standard theory of mind tasks, new techniques were used that were able to separate out the various processing demands of the task (e.g., memory, inhibitory control). Overall, the findings indicate that both groups of boys with FXS have difficulty with theory of mind tasks compared to an intellectual disability control group. However, both groups with FXS also performed worse on comparison trials that required working memory but not theory of mind. Theory of mind difficulties are likely to be an important aspect of the FXS clinical profile, but are most likely the result from a more basic difficulty with working memory.

Language use in females with fragile X or Turner syndrome during brief initial social interactions

Fragile X and Turner syndromes are associated with risk of atypical social function. We examined language use, including normal and atypical speech, during initial social interactions among participants engaged in a brief social role play with an unfamiliar adult. There were 27 participants with Turner syndrome, 20 with fragile X syndrome and 28 in an age-matched comparison group. Females with fragile X did not exhibit more abnormal language, but exhibited less of what is typical during initial interactions. Overall rates of dysfluencies did not differ, although females with fragile X made more phrase repetitions. Females with Turner syndrome had no language use abnormalities. Our findings suggest that language use may influence social function in females with fragile X syndrome and that such language characteristics may be observed in the context of brief encounters with an unfamiliar adult.

Attention and language in fragile X

Fragile X syndrome (FXS) is a well-recognized cause of mental retardation and developmental delay in males. Alongside the well-documented clinical characteristics of the condition, recent advances in technology and methodology have begun to define FXS at a number of different levels: genetic, brain structure and function, cognition, and behavior. This article suggests that the FXS phenotype is not merely a juxtaposition of spared and impaired functions but rather may be characterized by an inhibitory control deficit that interferes with the individual's ability to modulate output causing perseverative responding across various skill areas. It is further suggested that an inability to modulate arousal may be at least one cause for the inhibitory control deficit that typifies the FXS phenotype. The approach to understanding atypical development outlined here holds exciting promise for future research in FXS and other developmental disorders.

Behavioral assessment of social anxiety in females with Turner or fragile X syndrome

Social skills impairment in children with Turner or fragile X syndrome has been documented using parental reports. Anxiety, shyness, and difficulty understanding social cues have been reported for females with Turner syndrome; whereas social withdrawal, avoidance of social interactions, and anxiety are often reported for females with fragile X syndrome. Social interaction anxiety in these two populations may be a framework for understanding the difficulty these children experience in social situations. In the present study, 29 females with Turner syndrome and 21 females with fragile X syndrome ages 6-22 years were compared to females in a comparison group, on a videotaped role-play interaction. Behavioral indices examined included eye-contact maintenance, duration of speech, and body discomfort as observed during the brief interaction. Three of eight such behavioral measures of social skills differentiated the participant groups from each other. Specifically, participants with fragile X required more time to initiate interactions than did participants in either of the remaining groups; and females with Turner syndrome made fewer facial movements than did females in the fragile X or comparison group. Self-report and parental ratings did not suggest higher levels of anxiety in females with Turner or fragile X syndrome, but did reflect higher levels of social difficulty. The authors discuss these findings in terms of understanding the nature of social dysfunction in females with Turner or fragile X syndrome.

The behavioral phenotype in fragile X: symptoms of autism in very young children with fragile X syndrome, idiopathic autism, and other developmental disorders

This study was designed to explore the behavioral phenotype of autism in a group of young children with fragile X syndrome (FXS). Twenty-four children with FXS, ages 21 to 48 months, were compared with two well-matched groups: 27 children with autism (AD) and 23 children with other developmental delays (DD), on two standardized autism instruments, as well as on measures of development and adaptive behavior. Two FXS subgroups emerged. One subgroup (n = 16) did not meet study criteria for autism. Their profiles on the autism instruments and the developmental instruments were virtually identical to the other DD group. The other FXS subgroup (n = 8, or 33% of the total FXS group) met study criteria for autism. Their profiles on the autism instruments were virtually identical to the group with autism. The finding of two FXS subgroups raises a hypothesis of additional genetic influences in the FXS autism group, warranting further genetic studies.

Executive function and theory of mind performance of boys with fragile-X syndrome

Fragile-X syndrome is the most common genetically inherited cause of intellectual disability. People with this syndrome typically show a behavioural profile of abnormal social interactions which are similar in some ways to those seen in people with autism. The present study investigated whether cognitive processes which have been hypothesized to underlie social abnormalities associated with autism are also impaired in boys with fragile-X syndrome without autistic spectrum disorders. Eight boys with fragile-X syndrome and eight with intellectual disability of unknown aetiology, matched on receptive verbal ability, age and with no diagnosis of autism, were tested on a battery of theory of mind and executive function tasks. Significantly more boys with fragile-X syndrome failed the simplest theory of mind task. However, this could be attributed to overall level of ability rather than group membership. No differences were found between the groups on any other measures used. A proportion of both groups failed first- and second-order false belief tasks. The performance of both groups on the executive function measure was at the floor of the test. At low levels of overall ability, the performance of boys with fragile-X syndrome and boys with intellectual disability of unknown aetiology may be more similar than they are different The implication of this result for clinical interventions is discussed.

Face recognition and emotion perception in boys with fragile-X syndrome

Two independent and complementary studies were conducted to assess the ability of boys with fragile-X syndrome to recognize facial and emotional expressions. Both studies failed to find any specific deficits associated with fragile-X syndrome. The performance of the test group was comparable to the level of subjects with intellectual disability and subjects of average cognitive development matched for intellectual ability. This suggests that chronological age and intellectual level are unlikely to explain the findings. The results are discussed in the context of the controversy surrounding the relationship between autism and fragile-X syndrome. The findings are consistent with fragile-X individuals having a profile of social, communicatory and ritualistic disturbances, which in some ways may differ from those found in individuals who have more typical autistic spectrum disorders.

Autism: the point of view from fragile X studies

The relationship between the fragile X syndrome (FXS) and autism is reviewed. Shortly after the FXS was first described, it was noted that certain behaviors commonly found in afflicted individuals resemble certain features of autism. Research concerning a possible relationship between these conditions is summarized. The outcome of this research indicates that FXS is not a common cause of autism, although the number of individuals with FXS who meet diagnostic criteria for autism is higher than can be accounted for by chance. The major focus of this paper highlights that FXS is a well-defined neurogenetic disease that includes a cognitive behavioral phenotype, and has both a known biological cause and an increasing well-delineated pathogenesis. Autism is a behaviorally defined syndrome whose syndromic boundaries and biological causes are not known. These profound differences complicate comparisons and causal discussions. However, the behavioral neurogenetic information available about FXS suggests certain pathways for future research directed at elucidating the syndrome of autism.

Facial emotion identification in males with fragile X syndrome

Fifteen postpubertal males with fragile X syndrome (FRA(X)) and 15 non-FRA(X) males matched on IQ and age were assessed for their ability to identify the facially expressed emotions of happiness, sadness, anger, fear, disgust, and surprise. Emotions of happiness and sadness were the easiest to identify for both groups of participants. Regardless of etiology, individuals with higher IQ scores performed better at this task than did individuals with lower IQ scores. Results were consistent with findings in females having the fragile X mutation. The current study supported the notion that FRA(X) individuals are sensitive to facial emotion cues presented by others. This finding is discussed in the context of autism and gaze aversion.

Autism: towards an integration of clinical, genetic, neuropsychological, and neurobiological perspectives

Autism constitutes one of the best validated child psychiatric disorders. Empirical research has succeeded in delineating the key clinical phenomena, in demonstrating strong genetic influences on the underlying liability, and in identifying basic cognitive deficits. A range of neurobiological abnormalities has also been found, although the replicability of specific findings has not been high. An understanding of the causal processes leading to autism, and accounting for the marked variability in its manifestations, requires an integration across these different levels of enquiry. Although this is not yet possible, a partial integration provides a useful strategy for identifying key research questions, the limitations of existing hypotheses, and future research directions that are likely to prove fruitful. The research findings for each research level are critically reviewed in order to consider how to move towards an integration across levels.