BackgroundFragile X syndrome (FXS) is the leading inherited cause of autism spectrum disorder, but there remains debate regarding the clinical presentation of social deficits in FXS. The aim of this study was to compare individuals with FXS to typically developing controls (TDC) and individuals with idiopathic autism spectrum disorder (ASD) across two social eye tracking paradigms.MethodsIndividuals with FXS and age- and gender-matched TDC and individuals with idiopathic ASD completed emotional face and social preference eye tracking tasks to evaluate gaze aversion and social interest, respectively. Participants completed a battery of cognitive testing and caregiver-reported measures for neurobehavioral characterization.ResultsIndividuals with FXS exhibited reduced eye and increased mouth gaze to emotional faces compared to TDC. Gaze aversive findings were found to correlate with measures of anxiety, social communication deficits, and behavioral problems. In the social interest task, while individuals with idiopathic ASD showed significantly less social preference, individuals with FXS displayed social preference similar to TDC.ConclusionsThese findings suggest fragile X syndrome social deficits center on social anxiety without the prominent reduction in social interest associated with autism spectrum disorder. Specifically designed eye tracking techniques clarify the nature of social deficits in fragile X syndrome and may have applications to improve phenotyping and evaluate interventions targeting social functioning impairments.

Aggression, self-injurious behavior, and severe tantrums are impairing symptoms frequently experienced by individuals with autism spectrum disorders. Despite US Food and Drug Administration approval of two atypical antipsychotics targeting these symptoms in youth with autistic disorder, they remain frequently drug refractory. We define drug-refractory aggression, self-injurious behavior, and severe tantrums in people with autism spectrum disorders as behavioral symptoms requiring medication adjustment despite previous trials of risperidone and aripiprazole or previous trials of three psychotropic drugs targeting the symptom cluster, one of which was risperidone or aripiprazole. We reviewed the medical records of individuals of all ages referred to our clinic for autism spectrum disorder diagnostic evaluation, as well as pharmacotherapy follow-up notes for all people meeting autism spectrum disorder criteria, for drug-refractory symptoms. Among 250 consecutively referred individuals, 135 met autism spectrum disorder and enrollment criteria, and 53 of these individuals met drug-refractory symptom criteria. Factors associated with drug-refractory symptoms included age 12 years or older (p < 0.0001), diagnosis of autistic disorder (p = 0.0139), and presence of intellectual disability (p = 0.0273). This pilot report underscores the significance of drug-refractory aggression, self-injurious behavior, and severe tantrums; suggests the need for future study clarifying factors related to symptom development; and identifies the need for focused treatment study of this impairing symptom domain.

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Executive function (EF) supports goal-directed behavior and includes key aspects such as working memory, inhibitory control, cognitive flexibility, attention, processing speed, and planning. Fragile X syndrome (FXS) is the leading inherited monogenic cause of intellectual disability and is phenotypically characterized by EF deficits beyond what is expected given general cognitive impairments. Yet, a systematic review of behavioral studies using performance-based measures is needed to provide a summary of EF deficits across domains in males and females with FXS, discuss clinical and biological correlates of these EF deficits, identify critical limitations in available research, and offer suggestions for future studies in this area. Ultimately, this review aims to advance our understanding of the underlying pathophysiological mechanisms contributing to EF in FXS and to inform the development of outcome measures of EF and identification of new treatment targets in FXS.

The use of eye tracking and pupillometry may represent an innovative measure for quantifying AS-associated impairments in social salience.

Frontiers in Integrative Neuroscience | www.frontiersin.org February 2020 | Volume 13 | Article 76 Reisinger et al. Social Attention in ASDfor identifying social attention and emotion recognition deficits in ASD. Detecting differences in emotion recognition explicitly through facial scanning was not as clear. Specific mechanisms within the eye-tracking paradigm may be viable options for assessing treatment-specific outcomes.

The current study evaluates the psychometric properties of the Behavior Rating Inventory of Executive Function (BRIEF) with children with Down syndrome. Caregivers of 84 children with Down syndrome rated their child's behavior with the BRIEF. Teacher ratings were obtained for 57 children. About 40% of children with Down syndrome were reported by parents, and 70% by teachers, to exhibit clinically significant challenges with executive functioning. Distribution of scores was normal, internal consistency for subscales was questionable to primarily excellent, and inter-rater reliability was poor to good. Normative data conversions controlled for age, IQ, and gender differences, with some exceptions. The study findings suggest that the BRIEF and its subscales generally performed in a psychometrically sound manner among children with Down syndrome.

Fragile X Syndrome (FXS) is a monogenetic form of intellectual disability and autism in which well-established knockout (KO) animal models point to neuronal hyperexcitability and abnormal gamma-frequency physiology as a basis for key disorder features. Translating these findings into patients may identify tractable treatment targets. Using source modeling of resting-state electroencephalography data, we report findings in FXS, including 1) increases in localized gamma activity, 2) pervasive changes of theta/alpha activity, indicative of disrupted thalamocortical modulation coupled with elevated gamma power, 3) stepwise moderation of low and high-frequency abnormalities based on female sex, and 4) relationship of this physiology to intellectual disability and neuropsychiatric symptoms. Our observations extend findings in Fmr1−/− KO mice to patients with FXS and raise a key role for disrupted thalamocortical modulation in local hyperexcitability. This systems-level mechanism has received limited preclinical attention but has implications for understanding fundamental disease mechanisms.