Corpus callosum metrics predict severity of visuospatial and neuromotor dysfunctions in ARID1B mutations with Coffin-Siris syndrome.

ARID1B mutations in Coffin-Siris syndrome are a cause of intellectual disability (0.5-1%), with various degrees of autism and agenesis of the corpus callosum (10%). Little is known regarding the cognitive and motor consequences of ARID1B mutations in humans and no link has been made between corpus callosum anomalies and visuospatial and neuromotor dysfunctions. We have investigated the visuospatial and neuromotor phenotype in eight patients with ARID1B mutations. A paramedian sagittal section of the brain MRI was selected, and corpus callosum was measured in anteroposterior length, genu and trunk width. Spearman's rank order coefficients were used to explore correlations between visuospatial and social cognitive variables and dimensions of the corpus callosum. A significant correlation between genu width size and visual cognition was observed. Retrocerebellar cysts were associated with corpus callosum anomalies. Here, we show that corpus callosum anomalies caused in ARID1B mutations may be predictive of the visuospatial and motor phenotype in Coffin-Siris syndrome.

Developmental dysgraphia is often associated with minor neurological dysfunction in children with developmental coordination disorder (DCD).

OBJECTIVES: Children with developmental coordination disorder (DCD) are particularly affected by handwriting disorders, which remain poorly understood and are not clearly defined. The aim of our study is to provide a better understanding of handwriting disorders, and specifically of dysgraphia in children with DCD. METHODS: Sixty-five children with DCD (5-15 years), enrolled according to DSM-5, were assessed with handwriting testing and standardized assessments of neuropsychological, neurovisual, MRI and neuropsychomotor functions, with special attention paid to muscular tone examination. RESULTS: While handwriting disorders were strongly represented in our sample of children with DCD (89%), dysgraphia appeared uncommon (17%) and was closely related to several specific dysfunctions of laterality establishment; mild pyramidal tract dysfunction with distal phasic stretch reflex (PSR) in lower limbs; digital praxis slowness (both P<0.05). DISCUSSION: In our sample, dysgraphia was closely related to minor neurological dysfunction (MND) suggesting a disturbance of motor control at the level of the corticospinal motor pathway. This highlights the uncommon character of dysgraphia in children with DCD for which diagnosis should be made through a particular attention to evaluation of MND with muscular tone examination. This consideration, both in the research setting and in clinical practice, appears necessary to avoid inaccurate clinical diagnosis and to optimize appropriate therapeutic management.

From High Intellectual Potential to Asperger Syndrome: Evidence for Differences and a Fundamental Overlap-A Systematic Review.

Background: An increasing number of clinicians point to similar clinical features between some children with High Intellectual Potential (HIP or "Giftedness" = Total IQ > 2 SD), and children with Autism Spectrum Disorder (ASD) without intellectual or language delay, formerly diagnosed with Asperger Syndrome. Some of these common features are social interaction impairments, special interests, and in some cases high-verbal abilities. The aim of this article is to determine whether these similarities exist at more fundamental levels, other than clinical, and to explore the literature in order to provide empirical support for an overlap between ASD and HIP. Method: First, comparative studies between ASD and HIP children were sought. Because of a lack of data, the respective characteristics of ASD and HIP subjects were explored by a cross-sectional review of different areas of research. Emphasis was placed on psychometric and cognitive evaluations, experimental and developmental assessments, and neurobiological research, following a "bottom-up" procedure. Results: This review highlights the existence of similarities in the neurocognitive, developmental and neurobiological domains between these profiles, which require further study. In addition, the conclusions of several studies show that there are differences between HIP children with a homogeneous Intellectual Quotient profile and children with a heterogeneous Intellectual Quotient profile. Conclusion: HIP seems to cover different developmental profiles, one of which might share features with ASD. A new line of investigation providing a possible starting-point for future research is proposed. Its implications, interesting from both clinical and research perspectives, are discussed.