Sleep problems in fragile X syndrome: Cross-sectional analysis of a large clinic-based cohort.

Fragile X syndrome (FXS), the leading cause of inherited intellectual disability and autism spectrum disorder, is associated with multiple neurobehavioral abnormalities including sleep difficulties. Nonetheless, frequency, severity, and consequences of sleep problems are still unclear. The Fragile X Online Registry with Accessible Research Database (FORWARD-version-3), including Clinician Report and Parent Report forms, was analyzed for frequency, severity, relationship with behavioral problems, and impact of sleep difficulties in a mainly pediatric cohort. A focused evaluation of sleep apnea was also conducted. Six surveyed sleep difficulties were moderately frequent (~23%-46%), relatively mild, affected predominantly younger males, and considered a problem for 7%-20% of families. Snoring was more prevalent in older individuals. All sleep difficulties were associated with irritability/aggression and most also to hyperactivity. Only severe snoring was correlated with sleep apnea (loud snoring: 30%; sleep apnea: 2%-3%). Sleep difficulties are prevalent in children with FXS and, although they tend to be mild, they are associated with behavioral problems and negative impact to families. Because of its cross-sectional nature, clinic-origin, use of ad hoc data collection forms, and lack of treatment data, the present study should be considered foundational for future research aiming at better recognition and management of sleep problems in FXS.

Further evidence of GABRA4 and TOP3B as autism susceptibility genes.

Chromosomal copy number variants (CNVs) are known contributors to neurodevelopmental conditions such as autism spectrum disorder (ASD). Both array comparative genomic hybridization and next-generation sequencing techniques have led to an increased detection of small CNVs and the identification of many candidate susceptibility genes for ASD. We report familial inheritance of two CNVs that include genes with known involvement in neurodevelopment. These CNVs are found in various combinations among four siblings with autism spectrum disorder, as well as in their neurodevelopmentally normal parents. We describe a 2.4 Mb duplication of 4p12 to 4p11 that includes GABRA4 (OMIM: 137141) and other GABA receptor genes, as well as a 246 kb deletion at 22q11.22 involving the TOP3B gene (OMIM: 603582). The maternally inherited 4p duplication was detected in three siblings, two of whom also had the paternally inherited 22q11.22 deletion. The fourth sibling only had the 22q11.22 deletion. These CNVs have rarely been reported in the literature. Upon review, a single publication was found describing a similar 4p duplication in three generations of a family with neurodevelopmental and neuropsychiatric disorders, as well as in an unrelated patient with autism (Polan et al., 2014). TOP3B falls within the distal 22q11.22 microdeletion syndrome and has been associated with schizophrenia, neurodevelopmental disorders including epilepsy, and cardiac defects. The identification of this family contributes to the understanding of specific genetic contributors to neurodevelopmental disorders and an emerging phenotype associated with proximal 4p duplication.

Development of an Objective Autism Risk Index Using Remote Eye Tracking.

OBJECTIVE: Abnormal eye gaze is a hallmark characteristic of autism spectrum disorder (ASD), and numerous studies have identified abnormal attention patterns in ASD. The primary aim of the present study was to create an objective, eye tracking-based autism risk index. METHOD: In initial and replication studies, children were recruited after referral for comprehensive multidisciplinary evaluation of ASD and subsequently grouped by clinical consensus diagnosis (ASD n = 25/15, non-ASD n = 20/19 for initial/replication samples). Remote eye tracking was blinded to diagnosis and included multiple stimuli. Dwell times were recorded to each a priori-defined region of interest (ROI) and averaged across ROIs to create an autism risk index. Receiver operating characteristic curve analyses examined classification accuracy. Correlations with clinical measures evaluated whether the autism risk index was associated with autism symptom severity independent of language ability. RESULTS: In both samples, the autism risk index had high diagnostic accuracy (area under the curve [AUC] = 0.91 and 0.85, 95% CIs = 0.81-0.98 and 0.71-0.96), was strongly associated with Autism Diagnostic Observation Schedule-Second Edition (ADOS-2) severity scores (r = 0.58 and 0.59, p < .001), and not significantly correlated with language ability (r ≤| -0.28|, p > .095). CONCLUSION: The autism risk index may be a useful quantitative and objective measure of risk for autism in at-risk settings. Future research in larger samples is needed to cross-validate these findings. If validated and scaled for clinical use, this measure could inform clinical judgment regarding ASD diagnosis and track symptom improvements.

Developmental delays and autism: Screening and surveillance.

Screening and surveillance are crucial components to the early detection of developmental disorders in children, which enables early interventions that provide the best chances for improved outcomes. Identifying a developmental disorder is the initial step in evaluating the disorder. Surveillance is a flexible, continuous, longitudinal process aimed at identifying concerns, and it should be performed at every well-child visit. Screening involves administering a brief, standardized tool normalized for specific ages and stages of development to identify any developmental delays or specific concerns such as autism. Screening is recommended at every office visit and whenever a parent expresses a concern. Two general types of screening tests are available: problem-specific screening and broadband developmental screening. For each type, there are multiple different tests available that can be administered by a parent or a health care provider. Factors to consider in the test selection are the age range for which it is intended, time it takes to complete and score, cost, whether the test is paper-based or electronic, and the language availability.

Fragile X syndrome: a review of associated medical problems.

Fragile X syndrome (FXS) is the most common known genetic cause of inherited intellectual disability and the most common known single-gene cause of autism spectrum disorder. It has been reported that a spectrum of medical problems are commonly experienced by people with FXS, such as otitis media, seizures, and gastrointestinal problems. Previous studies examining the prevalence of medical problems related to FXS have been challenging to interpret because of their marked differences in population, setting, and sampling. Through this comprehensive review, we update the literature by reviewing studies that have reported on prominent medical problems associated with FXS. We then compare prevalence results from those studies with results from a large cross-sectional database consisting of data collected by fragile X clinics that specialize in the care of children with FXS and are part of the Fragile X Clinical and Research Consortium. It is vital for pediatricians and other clinicians to be familiar with the medical problems related to FXS so that affected patients may receive proper diagnosis and treatment; improved care may lead to better quality of life for these patients and their families.

Advances in the treatment of fragile X syndrome.

The FMR1 mutations can cause a variety of disabilities, including cognitive deficits, attention-deficit/hyperactivity disorder, autism, and other socioemotional problems, in individuals with the full mutation form (fragile X syndrome) and distinct difficulties, including primary ovarian insufficiency, neuropathy and the fragile X-associated tremor/ataxia syndrome, in some older premutation carriers. Therefore, multigenerational family involvement is commonly encountered when a proband is identified with a FMR1 mutation. Studies of metabotropic glutamate receptor 5 pathway antagonists in animal models of fragile X syndrome have demonstrated benefits in reducing seizures, improving behavior, and enhancing cognition. Trials of metabotropic glutamate receptor 5 antagonists are beginning with individuals with fragile X syndrome. Targeted treatments, medical and behavioral interventions, genetic counseling, and family supports are reviewed here.