[Show abstract][Hide abstract] ABSTRACT: Smith-Magenis syndrome is a complex neurodevelopmental disorder that includes intellectual deficiency, speech delay, behavioral disturbance and typical sleep disorders. Ninety percent of the cases are due to a 17p11.2 deletion encompassing the RAI1 gene; other cases are linked to mutations of the same gene. Behavioral disorders often include outbursts, attention deficit/hyperactivity disorders, self-injury with onychotillomania and polyembolokoilamania (insertion of objects into body orifices), etc. Interestingly, the stronger the speech delay and sleep disorders, the more severe the behavioral issues. Sleep disturbances associate excessive daytime sleepiness with nighttime agitation. They are underpinned by an inversion of the melatonin secretion cycle. However, the combined intake of beta-blockers in the morning and melatonin in the evening may radically alleviate the circadian rhythm problems.
Once sleep disorders are treated, the next challenge is finding an effective treatment for the remaining behavioral problems. Unfortunately, there is a lack of objective guidelines. A comprehensive evaluation of such disorders should include sleep disorders, potential causes of pain, neurocognitive level and environment (i.e. family and school). In any case, efforts should focus on improving communication skills, identifying and treating attention deficit/hyperactivity, aggressiveness and anxiety. Treatment of Smith-Magenis syndrome is complex and requires a multidisciplinary team including, among others, geneticists, psychiatrists, neuropediatricians/neurologists, somnologists, developmental and behavioral pediatricians, and speech and language therapists.
[Show abstract][Hide abstract] ABSTRACT: Infantile spasms syndrome (ISs) is characterized by clinical spasms with ictal electrodecrement, usually occurring before the age of 1 year and frequently associated with cognitive impairment. Etiology is widely heterogeneous, the cause remaining elusive in 40% of patients. We searched for de novo mutations in 10 probands with ISs and their parents using whole-exome sequencing (WES). Patients had neither consanguinity nor family history of epilepsy. Common causes of ISs were excluded by brain MRI, metabolic screening, array-CGH and testing for mutations in CDKL5, STXBP1, and for ARX duplications. We found a probably pathogenic mutation in four patients. Missense mutations in SCN2A (p.Leu1342Pro) and KCNQ2 (p.Ala306Thr) were found in two patients with no history of epilepsy before the onset of ISs. The p.Asn107Ser missense mutation of ALG13 had been previously reported in four females with ISs. The fourth mutation was an in-frame deletion (p.Phe110del) in NR2F1, a gene whose mutations cause intellectual disability, epilepsy, and optic atrophy. In addition, we found a possibly pathogenic variant in KIF3C that encodes a kinesin expressed during neural development. Our results confirm that WES improves significantly the diagnosis yield in patients with sporadic ISs.
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[Show abstract][Hide abstract] ABSTRACT: Le syndrome de Smith-Magenis (SMS) est une affection génétique se manifestant essentiellement par une déficience intellectuelle associée à un important retard de langage, des signes morphologiques reconnaissables, des troubles du comportement et du sommeil. Il est lié dans 90 % des cas à une microdélétion localisée sur le bras court du chromosome 17 en 17p11.2. Plus rarement, il s’agit d’une mutation ponctuelle du gène RAI1, situé dans cette même région chromosomique. Les troubles du comportement sont variés, majorés par le retard de langage et les troubles du sommeil. Ces derniers sont liés à une inversion de la sécrétion de mélatonine perturbant le cycle nycthéméral et entraînant une agitation nocturne et diurne. L’association des troubles du sommeil et des troubles comportementaux, qui en résultent partiellement, met en péril le parcours scolaire de l’enfant et impacte l’équilibre familial. Il n’y a actuellement aucune recommandation clinique pour ce syndrome. Néanmoins, avec une prise en charge adaptée, il est possible de rétablir un rythme de sommeil normal et d’améliorer le comportement. La prescription médicamenteuse associe généralement la prise de β-bloquants le matin (pour limiter la sécrétion diurne de mélatonine) et de mélatonine le soir (pour remplacer le pic déficitaire). Parallèlement, il faut identifier et prendre en charge de manière spécifique une éventuelle hyperactivité ou agressivité. L’amélioration des capacités de communication et les soins de stimulation (orthophonie, psychomotricité, remédiation cognitive) sont un élément thérapeutique central. Cet article reprend les principaux éléments cliniques et paracliniques du syndrome de Smith-Magenis et propose une prise en charge adaptée aux différentes étapes de la vie de l’enfant.
Archives de Pédiatrie 04/2015; 22(6). DOI:10.1016/j.arcped.2015.03.015 · 0.41 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Heterozygous dominant mutations of PRRT2 have been associated with various types of paroxysmal neurological manifestations, including benign familial infantile convulsions and paroxysmal kinesigenic dyskinesia. The phenotype associated with biallelic mutations is not well understood as few cases have been reported.
PRRT2 screening was performed by Sanger sequencing and quantitative multiplex PCR of short fluorescent fragments. A CGH array was used to characterise the size of the deletion at the 16p11.2 locus.
Five patients with homozygous or compound heterozygous deleterious PRRT2 gene mutations are described. These patients differ from those with a single mutation by their overall increased severity: (1) the combination of at least three different forms of paroxysmal neurological disorders within the same patient and persistence of paroxysmal attacks; (2) the occurrence of uncommon prolonged episodes of ataxia; and (3) the association of permanent neurological disorders including learning difficulties in four patients and cerebellar atrophy in 2.
Our observations expand the phenotype related to PRRT2 insufficiency, and highlight the complexity of the phenotype associated with biallelic mutations, which represents a severe neurological disease with various paroxysmal disorders and frequent developmental disabilities.
Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://group.bmj.com/group/rights-licensing/permissions.
[Show abstract][Hide abstract] ABSTRACT: The strong positive-allometric relationship between brain size, cortical extension and gyrification complexity, recently highlighted in the general population, could be modified by brain developmental disorders. Indeed, in case of brain growth insufficiency, the pathophysiological relevance of the “simplified gyral pattern” phenotype is strongly disputed since almost no genotype–phenotype correlations have been found in primary microcephalies. Using surface scaling analysis and newly-developed spectral analysis of gyrification (Spangy), we tested whether the gyral simplification in groups of severe microcephalies related to ASPM, PQBP1 or fetal-alcohol-syndrome could be fully explained by brain size reduction according to the allometric scaling law established in typically-developing control groups, or whether an additional disease effect was to be suspected. We found the surface area reductions to be fully explained by scaling effect, leading to predictable folding intensities measured by gyrification indices. As for folding pattern assessed by spectral analysis, scaling effect also accounted for the majority of the variations, but an additional negative or positive disease effect was found in the case of ASPM and PQBP1-linked microcephalies, respectively. Our results point out the necessity of taking allometric scaling into account when studying the gyrification variability in pathological conditions. They also show that the quantitative analysis of gyrification complexity through spectral analysis can enable distinguishing between even (predictable, non-specific) and uneven (unpredictable, maybe disease-specific) gyral simplifications.
[Show abstract][Hide abstract] ABSTRACT: Background
Neurofibromatosis type 1 (NF1) is an autosomal dominant disorder with an estimated prevalence of about 1/3000, independent of ethnicity, race, or gender. Attention Deficit Hyperactivity like Disorder (ADHD)-like characteristics are often reported in patients with NF1. We hypothesised that learning disabilities in NF1 children were related to ADHD symptoms. Treatment with methylphenidate (MPD) has improved learning disabilities in ADHD by acting on neurotransmitters. Our objective was to evaluate its efficacy on ADHD-like symptoms in neurofibromatosis type 1 children (7¿12 years).Methods
This was a randomised, double blind, placebo controlled, and crossover trial comparing 0.5 to 0.8 mg/kg/d of MPD as it is indicated for ADHD to placebo in NF1 children with ADHD-like symptoms. Children aged 7 to 12 years were eligible when their IQ was between 80 and 120. The total follow-up was 9 weeks including 4 weeks for each period and 1 week wash out. Fifty subjects (25 for each period) were required for testing the primary study hypothesis. The main outcome was an improvement in scores on the simplified Conners¿ Parent Rating Scale.ResultsThirty-nine patients were included between April 2004 and December 2010. Twenty participants received MPD and 19 placebo during the first period. They all completed the trial. MPD decreased the simplified Conners by 3.9 points (±1.1, p¿=¿0. 0003).Conclusions
This is the first randomised controlled trial showing the short-term benefit of MPD on simplified Conners scores in NF1 children.Trial registrationClinicalTrials.gov NCT00169611.
[Show abstract][Hide abstract] ABSTRACT: 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.
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.
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.
These findings suggest that the ARX c.429_452dup24 mutation may be a developmental model for Limb Kinetic Apraxia.
[Show abstract][Hide abstract] ABSTRACT: The present paper investigates the clinical picture and the different clinical signs that reveal pineal region tumors or appear during the course of the follow-up. Biological malignancy and tumor extension determine the semiology and its setting up mode. Typical endocrine signs, dominated by abnormal puberty development, are frequently a part of the clinical scene. Bifocal or ectopic localization in the hypothalamic-pituitary region is accompanied by other endocrine signs such as ante- or post-pituitary insufficiencies which occur several months or even years after the first neurological signs appear. Due to a mass syndrome and obstructive hydrocephalus, intracranial hypertension signs are frequent but unspecific. A careful ophthalmologic examination is essential to search upward gaze paralysis and other signs of the Parinaud's tetrad or pentad. Midbrain dysfunction, including extrinsic aqueduct stenosis, are also prevalent. Except for abnormal pubertal signs, hyper-melatoninemia (secretory tumors) or a-hypo-melatoninemia (tumors destructing pineal) generally remains dormant. Some patients present sleep problems such as narcolepsy or sleepiness during the daytime as well as behavioral problems. This suggests a hypothalamic extension rather than a true consequence of melatonin secretion anomalies. Similarly, some patients may present signs of a "pinealectomized" syndrome, including (cluster) headaches, tiredness, eventually responsive to melatonin.
[Show abstract][Hide abstract] ABSTRACT: Ten percent of cases of intellectual deficiency in boys are caused by genes located on the X chromosome. X-linked mental retardation (XLMR) includes more than 200 syndromes and 80 genes identified to date. The fragile X syndrome is the most frequent syndrome, due to a dynamic mutation with a CGG triplet amplification. Mental retardation is virtually always present. Phonological and syntactic impairments are often combined with pragmatic language impairment and visuospatial reasoning difficulties. A minority fulfill the criteria for autism. In girls, the clinical expression of the complete mutation varies according to the X chromosome inactivation profile. Several XLMR occur as severe early onset encephalopathies: Lowe oculocerebrorenal syndrome, ATR-X syndrome (alpha thalassemia/mental retardation X-linked), Allan-Herdon-Dudley syndrome (MCT8 gene). Two genes, ARX (X-LAG; Partington syndrome) and MECP2 (Rett syndrome in females; mild MR with spastic diplegia/psychotic problems in males) are associated with various phenotypes, according to the mutation involved. Oligophrenine 1 (OPHN-1) gene mutations lead to vermal dysplasia. PQBP1 gene mutations (Renpenning syndrome) are responsible for moderate to severe mental deficiency, microcephaly, and small stature. Although some forms of XLMR are not very specific and the phenotype for each given gene is somewhat heterogeneous, a clinical diagnostic strategy is emerging.
Handbook of Clinical Neurology 12/2013; 111:297-306. DOI:10.1016/B978-0-444-52891-9.00035-X
[Show abstract][Hide abstract] ABSTRACT: L'invention concerne un dispositif (1) d'évaluation des capacités cognitives, comprenant: - un dispositif d'affichage (3) ; - un dispositif de test (2) configuré pour localiser l'emplacement du dispositif d'affichage fixé par un oeil du patient et effectuer automatiquement la séquence suivante: - l'affichage (3) d'un visuel de test ; - déterminer le nombre de transitions du regard entre une matrice et des propositions de réponse ; - répéter la séquence pour plusieurs visuels de test.
[Show abstract][Hide abstract] ABSTRACT: To identify the aetiology of patients with infantile spasms and propose practical guidelines for diagnostic strategies.
We performed a retrospective study of children with West syndrome. Prenatal and birth medical history, characteristics of epilepsy, psychomotor development, biological and genetic screening, and aetiology were reported. Brain MRI was performed at least once and was repeated after two years of age if no aetiology was identified.
Eighty children were included. Aetiology was identified in 40 children: 17 with acquired cause (seven with stroke and six with hypoxic-ischaemic encephalopathy) and 23 with developmental pathology (seven with tuberous sclerosis, eight with cerebral malformations, and eight with various genetic abnormalities). The yield of brain imaging was high, providing a diagnosis for 32 patients. Two subtle brain lesions were detected only after two years of age, based on subsequent MRI. Genetic testing provided a diagnosis for the remaining eight patients.
Although this is a retrospective study, the results provide a basis to review the aetiology of infantile spasms and confirm the role of cerebral MRI in first-line diagnosis. Cases with a genetic aetiology have been diagnosed with increasing frequency due to better diagnostic capabilities. We propose guidelines for a practical diagnostic approach and discuss the relevant use of genetics in the future.
European journal of paediatric neurology: EJPN: official journal of the European Paediatric Neurology Society 11/2013; 18(2). DOI:10.1016/j.ejpn.2013.11.005 · 2.30 Impact Factor