Placebo Responses in Genetically Determined Intellectual Disability: A Meta-Analysis

Background: Genetically determined Intellectual Disability (ID) is an intractable condition that involves severe impairment of mental abilities such as learning, reasoning and predicting the future. As of today, little is known about the placebo response in patients with ID. Objective: To determine if placebo response exists in patients with genetically determined ID. Data sources and Study selection We searched Medline/PubMed, EMBASE, CENTRAL and PsycINFO to find all placebo-controlled double-blind randomized clinical trials (RCTs) in patients with genetically determined ID, published up to April 2013, focusing on core ID symptoms. Data extraction and synthesis Two investigators extracted outcome data independently. Main outcomes and measures Bias-corrected standardized mean difference (Hedge’s g) was computed for each outcome measure, using the Comprehensive Meta-Analysis software. A priori defined patient sub-groups were analyzed using a mixed-effect model. The relationship between pre-defined continuous variable moderators (age, IQ, year of publication and trial duration) and effect size was analyzed using meta-regression Results: Twenty-two placebo-controlled double-blind RCTs met the inclusion criteria (n = 721, mean age = 17.1 years, 62% men, mean trial duration = 35 weeks). There was a significant overall placebo response from pre- to post-treatment in patients with ID (g = 0.468, p = 0.002), both for “subjective outcomes” (a third-person’s evaluation of the patient) (g = 0.563, p = 0.022) and “objective outcomes” (direct evaluation of the patient’s abilities) (g = 0.434, p = 0.036). Individuals with higher IQ had higher response to placebo (p = 0.02) and no placebo response was observed in ID patients with comorbid dementia. A significant effect of age (p = 0.02) was found, indicating higher placebo responses in treatment of younger patients. Conclusions and relevance Results suggest that patients with genetically determined ID improve in the placebo arm of RCTs. Several mechanisms may contribute to placebo effects in ID, including expectancy, implicit learning and “placebo-by-proxy” induced by clinicians/family members. As the condition is refractory, there is little risk that improvements are explained by spontaneous remission. While new avenues for treatment of genetically determined ID are emerging, our results demonstrate how contextual factors can affect clinical outcomes and emphasize the importance of being vigilant on the role of placebos when testing novel treatments in ID

Certainty of genuine treatment increases drug responses among intellectually disabled patients

Objective: To determine the placebo component of treatment responses in patients with intellectual disability (ID). Methods: A statistical meta-analysis comparing bias-corrected effect sizes (Hedges g) of drug responses in open-label vs placebo-controlled clinical trials was performed, as these trial types represent different certainty of receiving genuine treatment (100% vs 50%). Studies in fragile X, Down, Prader-Willi, and Williams syndrome published before June 2015 were considered. Results: Seventeen open-label trials (n = 261, 65% male; mean age 23.6 years; mean trial duration 38 weeks) and 22 placebo-controlled trials (n = 721, 62% male; mean age 17.1 years; mean trial duration 35 weeks) were included. The overall effect size from pre to post treatment in open-label studies was g = 0.602 (p = 0.001). The effect of trial type was statistically significant (p = 0.001), and revealed higher effect sizes in studies with 100% likelihood of getting active drug, compared to both the drug and placebo arm of placebo-controlled trials. We thus provide evidence for genuine placebo effects, not explainable by natural history or regression toward the mean, among patients with ID. Conclusions: Our data suggest that clinical trials in patients with severe cognitive deficits are influenced by the certainty of receiving genuine medication, and open-label design should thus not be used to evaluate the effect of pharmacologic treatments in ID, as the results will be biased by an enhanced placebo component

Mutations in TUBG1, DYNC1H1, KIF5C and KIF2A cause malformations of cortical development and microcephaly.

International audienceThe genetic causes of malformations of cortical development (MCD) remain largely unknown. Here we report the discovery of multiple pathogenic missense mutations in TUBG1, DYNC1H1 and KIF2A, as well as a single germline mosaic mutation in KIF5C, in subjects with MCD. We found a frequent recurrence of mutations in DYNC1H1, implying that this gene is a major locus for unexplained MCD. We further show that the mutations in KIF5C, KIF2A and DYNC1H1 affect ATP hydrolysis, productive protein folding and microtubule binding, respectively. In addition, we show that suppression of mouse Tubg1 expression in vivo interferes with proper neuronal migration, whereas expression of altered γ-tubulin proteins in Saccharomyces cerevisiae disrupts normal microtubule behavior. Our data reinforce the importance of centrosomal and microtubule-related proteins in cortical development and strongly suggest that microtubule-dependent mitotic and postmitotic processes are major contributors to the pathogenesis of MCD

Anxiety, concerns and COVID-19: Cross-country perspectives from families and individuals with neurodevelopmental conditions

BACKGROUND: The COVID-19 pandemic had a major impact on the mental health and well-being of children with neurodevelopmental conditions (NDCs) and of their families worldwide. However, there is insufficient evidence to understand how different factors (e.g., individual, family, country, children) have impacted on anxiety levels of families and their children with NDCs developed over time. METHODS: We used data from a global survey assessing the experience of 8043 families and their children with NDCs (mean of age (m) = 13.18 years, 37% female) and their typically developing siblings (m = 12.9 years, 45% female) in combination with data from the European Centre for Disease Prevention and Control, the University of Oxford, and the Central Intelligence Agency (CIA) World Factbook, to create a multilevel data set. Using stepwise multilevel modelling, we generated child-, family- and country-related factors that may have contributed to the anxiety levels of children with NDCs, their siblings if they had any, and their parents. All data were reported by parents. RESULTS: Our results suggest that parental anxiety was best explained by family-related factors such as concerns about COVID-19 and illness. Children’s anxiety was best explained by child-related factors such as children’s concerns about loss of routine, family conflict, and safety in general, as well as concerns about COVID-19. In addition, anxiety levels were linked to the presence of pre-existing anxiety conditions for both children with NDCs and their parents. CONCLUSIONS: The present study shows that across the globe there was a raise in anxiety levels for both parents and their children with NDCs because of COVID-19 and that country-level factors had little or no impact on explaining differences in this increase, once family and child factors were considered. Our findings also highlight that certain groups of children with NDCs were at higher risk for anxiety than others and had specific concerns. Together, these results show that anxiety of families and their children with NDCs during the COVID-19 pandemic were predicted by very specific concerns and worries which inform the development of future toolkits and policy. Future studies should investigate how country factors can play a protective role during future crises

The c.429_452 duplication of the ARX gene: a unique developmental-model of limb kinetic apraxia:

BACKGROUND: The c.429_452dup24 of the ARX gene is a rare genetic anomaly, leading to X-Linked Intellectual Disability without brain malformation. While in certain cases c.429_452dup24 has been associated with specific clinical patterns such as Partington syndrome, the consequence of this mutation has been also often classified as "non-specific Intellectual Disability". The present work aims at a more precise description of the clinical features linked to the c.429_452dup24 mutation. METHODS: We clinically reviewed all affected patients identified in France over a five-year period, i.e. 27 patients from 12 different families. Detailed cognitive, behavioural, and motor evaluation, as well as standardized videotaped assessments of oro-lingual and gestural praxis, were performed. In a sub-group of 13 ARX patients, kinematic and MRI studies were further accomplished to better characterize the motor impairment prevalent in the ARX patients group. To ensure that data were specific to the ARX gene mutation and did not result from low-cognitive functioning per se, a group of 27 age- and IQ-matched Down syndrome patients served as control. RESULTS: Neuropsychological and motor assessment indicated that the c.429_452dup24 mutation constitutes a recognizable clinical syndrome: ARX patients exhibiting Intellectual Disability, without primary motor impairment, but with a very specific upper limb distal motor apraxia associated with a pathognomonic hand-grip. Patients affected with the so-called Partington syndrome, which involves major hand dystonia and orolingual apraxia, exhibit the most severe symptoms of the disorder. The particular "reach and grip" impairment which was observed in all ARX patients, but not in Down syndrome patients, was further characterized by the kinematic data: (i) loss of preference for the index finger when gripping an object, (ii) major impairment of fourth finger deftness, and (iii) a lack of pronation movements. This lack of distal movement coordination exhibited by ARX patients is associated with the loss of independent digital dexterity and is similar to the distortion of individual finger movements and posture observed in Limb Kinetic Apraxia. CONCLUSION: These findings suggest that the ARX c.429_452dup24 mutation may be a developmental model for Limb Kinetic Apraxia

Chapter 9 - Intellectual disability

International audienceIntellectual disability (ID) or intellectual developmental disability (IDD) is one of the commonest neurodevelopmental disabilities worldwide and is known to affect 2% of the population of France or just over a million people. It is marked by a reduced ability to reason and understand abstract or complex information, which heavily restricts school learning and limits the individual's ability to adapt to daily life, including their transition to adulthood. Intellectual handicap or mental handicap results from an interaction between the individual vulnerability of a person with ID and their ecosystem, in other words, their family, and cultural and institutional environment, which can be a barrier or a facilitator. Identifying a child with an unusual developmental trajectory requires professionals to have a good understanding of psychomotor development. ID may be isolated but is very often intertwined with other neurodevelopmental disorders, including autism, motor or sensory difficulties (hearing, vision), serious sleep and eating disorders, and medical conditions such as epilepsy, as well as a wide variety of psychopathologic problems, including anxiety, depression, and emotional regulation disorders. There are many causes of ID. More than half of all cases are genetic in origin, and there are several hundreds of rare diseases about which little is known so far. The use of new genetic techniques (high-throughput sequencing) should reduce the number of people who are undiagnosed and give way to a comprehensive diagnostic approach based on clinical practice. A regular multidimensional evaluation of cognitive, educational, socioemotional, and adaptive skills throughout life provides a better understanding of how individuals with ID function and will contribute toward the planning of more appropriate strategies for learning, care, and support, leading to a better quality of life and participation in society

Approche développementale des fonctions exécutives : du bébé à l’adolescence

International audienceGiven the importance of the relationship between executive function (EF) and many aspects of child development - including the development of reasoning, emotion regulation, school performance, and wider self-regulation itself - research on the development of EF from infancy to the end of adolescence has become one of the scientific priorities of the last decade. Improving our knowledge on the maturative trajectory of EF and the functional weight of different internal and environmental factors, supposed to optimize their efficiency, can only promote a better understanding of EF and its role in the normal development of the child as well as of those at risk of poor outcome either because of neurodevelopmental disorders or psychopathological disorders. This article aims to update the recent literature in this area. It appears that executive function grows very gradually and evolves from a relatively simple and unitary model in young children to a more complex one - differentiated, integrated, and tripartite - in adolescence.Compte tenu de l’importance des relations entre les fonctions du développement de l’enfant – incluant le développement du raisonnement, la gestion des émotions et des performances scolaires et plus largement l’autorégulation de soi – les recherches sur le développement des FE de la prime enfance jusqu’à la fin de l’adolescence sont devenues une priorité scientifique de ces dix dernières années. L’amélioration de nos connaissances sur la trajectoire de maturation des FE et sur le poids fonctionnel des différents facteurs – internes et environnementaux – sensés optimiser leur efficience, ne peut que favoriser une meilleure compréhension des FE et de leur rôle dans le développement de l’enfant normal, ou de celui des enfants à risque d’évolution péjorative en raison de troubles du neuro-développement ou de troubles psychopathologiques. Cet article se propose de faire une mise au point de la littérature récente dans ce domaine. Il en ressort que les capacités exécutives mûrissent très progressivement et évoluent d’un fonctionnement relativement simple et unitaire chez le jeune enfant vers un mode de fonctionnement plus complexe – différencié, tripartite et intégré – à l’adolescence

Pontine Tegmental Cap Dysplasia (une nouvelle entité de dysplasie ponto-tegmentale : 5 nouveaux patients)

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