Silvia Esposito

MEF2C deletions and mutations versus duplications: A clinical comparison

5q14.3 deletions including the MEF2C gene have been identified to date using genomic arrays in patients with severe developmental delay or intellectual disability, stereotypic behavior, epilepsy, cerebral malformations and a facial gestalt not really distinctive though characterized by broad and/or high, bulging forehead, upslanting palpebral fissures, flat nasal root and bridge, small, upturned nose, hypotonic small mouth resulting in cupid bow/tented upper lip. MEF2C mutations have been also identified in patients with overlapping phenotype so that it is considered the gene responsible for the 5q14.3 deletion syndrome. To date, one single duplication including MEF2C has been reported in a patient with intellectual disability but its clinical significance remains uncertain also because of the large size of the imbalance. Here we present two further patients with 5q14.3 duplications including MEF2C. Their phenotype indeed suggest the pathogenic effect of the MEF2C duplication although other duplicated genes also brain expressed might contribute to the clinical features. In none of them a clear-cut syndrome can be identified. A comparison between MEF2C deleted/mutated and duplicated patients is also presented.

126 novel mutations in Italian patients with neurofibromatosis type 1.

Genetic analysis of Neurofibromatosis type 1 (NF1) may facilitate the identification of patients in early phases of the disease. Here, we present an overview of our diagnostic research spanning the last 11 years, with a focus on the description of 225 NF1 mutations, 126 of which are novel, found in a series of 607 patients (513 unrelated) in Italy. Between 2003 and 2013, 443 unrelated patients were profiled by denaturing high pressure liquid chromatography (DHPLC) analysis of 60 amplicons derived from genomic NF1 DNA and subsequent sequencing of heterozygotic PCR products. In addition, a subset of patients was studied by multiplex ligation‐dependent probe amplification (MLPA) to identify any duplications, large deletions or microdeletions present at the locus. Over the last year, 70 unrelated patients were investigated by MLPA and sequencing of 22 amplicons spanning the entire NF1 cDNA. Mutations were found in 70% of the 293 patients studied by DHPLC, thereby fulfilling the NIH criterion for the clinical diagnosis of NF1 (detection rate: 70%); furthermore, 87% of the patients studied by RNA sequencing were genetically characterized. Mutations were also found in 36 of the 159 patients not fulfilling the NIH clinical criteria. We confirmed a higher incidence of intellectual disability in patients harboring microdeletion type 1 and observed a correlation between a mild phenotype and the small deletion c.2970_2972delAAT or the missense alteration in amino acid residue 1809 (p.Arg1809Cys). These data support the use of RNA‐based methods for genetic analysis and provide novel information for improving the management of symptoms in oligosymptomatic patients.

Executive functions and cerebellar development in children

Abstract This article examines the role of the cerebellum in processing executive functions in developmental age. The areas implicated in its elaboration are interconnected in a network that includes the prefrontal cortex, the basal ganglia, and the cerebellum. Implementation of the capacities to plan and to control corresponds to the development of the network and its structures. The development, from an evolutionary point of view, of the most recent parts of the cerebellum and of its connections with the prefrontal cortex is tied to the crucial role that it plays in an inexorable way in action execution with implicit mechanisms of anticipation and control. Deficits in executive functions are present in many cerebellar pathologies and there is also an important link between motor development and the development of many higher-order cognitive and functional domains. Further studies are needed to clarify the role of the cerebellum in executive functions both in pathological or normal conditions in the developmental age.

Neuroimaging findings in 41 low-functioning children with autism spectrum disorder: A single-center experience

The data on the rate of brain imaging abnormalities in autistic spectrum disorders are still inconsistent. A recent study on patients with high-functioning autism found that approximately 90% of children had normal magnetic resonance imaging (MRI) scans whereas an unexpected high rate of MRI abnormalities was reported in 77 nonsyndromic autistic children with or without intellectual disability. The aim of this study was to evaluate the prevalence of neuroradiologic findings in low-functioning autistic children compared to controls matched for age. Minor brain abnormalities were found in 44% of patients and 22% of controls. Our main result is the high rate of mega cisterna magna in autistic patients. High rate of minor neuroradiologic abnormalities in low-functioning autistic patients could contribute to the research about the various endophenotypes and complete the clinical assessment of children with autistic spectrum disorder and intellectual disability.

Congenital Brain Damage: Cognitive Development Correlates With Lesion and Electroencephalographic Features

The purpose of this study was to assess cognitive development in 26 children with congenital focal brain lesion and unilateral spastic cerebral palsy first diagnosed and followed up for rehabilitation at our institution. Mean intelligence quotients (IQs) were correlated not only to the different features of the cerebral lesions, but also to the different types of electroencephalographic abnormalities. We also examined individual scores. We found that about 70% of the children had values of Full-Scale, Verbal, and Performance IQs within the normal range. No differences were found between left and right injured children. Different Verbal IQ–Performance IQ profiles were observed. Larger lesions and some electroencephalographic features, mainly signal slowing/attenuation as signs of structural brain damage, were significantly associated with lower intellectual abilities. The role of other factors, including genetic and environmental background variability, as well as rehabilitative treatments, on cognitive sequelae in such patients was discussed.

Vasculogenic and angiogenic pathways in moyamoya disease

BACKGROUND Moyamoya disease (MMD) is a slowly progressing steno-occlusive cerebrovascular disease. The typical moyamoya vessels, which originate from an initial stenosis of the internal carotid, highlight that increased and/or abnormal angiogenic, vasculogenic and arteriogenic processes are involved in the disease pathophysiology. OBJECTIVE Herein, we summarize the current knowledge on the most important signaling pathways involved in MMD vessel formation, particularly focusing on the expression of growth factors and function of endothelial progenitor cells (EPCs). METHODS AND RESULTS Higher plasma concentrations of vascular endothelial growth factor, matrix metalloproteinase, hepatocyte growth factor, and interleukin-1β were reported in MMD. A specific higher level of basic fibroblast growth factor was also found in the cerebrospinal fluid of these patients. Finally, the number and the functionality of EPCs were found to be increased. In spite of the available data, the approaches and findings reported so far do not give an evident correlation between the expression levels of the aforementioned growth factors and MMD severity. Furthermore, the controversial results provided by studies on EPCs, do not permit to understand the true involvement of these cells in MMD pathophysiology. CONCLUSION Further studies should thus be implemented to extend our knowledge on processes regulating both the arterial stenosis and the excessive formation of collateral vessels. Moreover, we suggest advances of integrated approaches and functional assays to correlate biological and clinical data, arguing for the development of new therapeutic applications for MMD.

Neurological pictures in Paediatric Chiari I malformation

The clinical features of Chiari I Malformation (CIM) may be related to the compression of dural and/or neural structures at the craniocervical junction or to the associated syringomyelia. Additionally, patients may exhibit symptoms and signs of associated disorders. CIM is a heterogeneous and multifactorial disorder including congenital and acquired forms; it can also be found as an isolated malformation or in association with many clinical conditions. We analyse the clinical features in a series of 65 children with CIM, focusing on the high frequency of associated clinical disorders. We emphasise the importance of a careful clinical and neurological assessment for a proper diagnosis and a correct management of these patients.

Low-Functioning Autism and Nonsyndromic Intellectual Disability Magnetic Resonance Imaging (MRI) Findings

Previous neuroradiologic studies reported a high incidence of abnormalities in low-functioning autistic children. In this population, it is difficult to know which abnormality depends on autism itself and which is related to intellectual disability associated with autism. The aim of this study was to evaluate the frequency of neuroradiologic abnormalities in low-functioning autistic children compared to Intellectual Quotient and age-matched nonsyndromic children, using the same set of magnetic resonance imaging (MRI) sequences. MRI was rated as abnormal in 44% of autistic and 54% of children with intellectual disability. The main results were mega cisterna magna in autism and hypoplastic corpus callosum in intellectual disability. These abnormalities are morphologically visible signs of altered brain development. These findings, more frequent than expected, are not specific to the 2 conditions. Although MRI cannot be considered mandatory, it allows an in-depth clinical assessment in nonsyndromic intellectual-disabled and autistic children.

A PDE10A de novo mutation causes childhood-onset chorea with diurnal fluctuations

Recently, de novo and bi-allelic mutations in PDE10A, encoding a cyclic nucleotide phosphodiesterase selectively expressed in striatal medium spiny neurons, have been recognized as a cause of childhood-onset chorea. Brain MRI consistently showed striking bilateral striatal lesions in the 3 patients with de novo mutations identified to date. Interestingly, these radiological features were not observed in any of the patients with recessive mutations despite a more severe clinical presentation. Herein, we describe a patient carrying a de novo PDE10A mutation presenting with bilateral striatal MRI abnormalities and a yet unreported circadian pattern of nonprogressive chorea. The patient is an Italian 5-year-old boy born full term after an uneventful pregnancy and delivery. Motor and language milestones were normally achieved. At age 2.5 he presented with subacute onset of chorea involving the lower limbs causing frequent falls. No febrile illness preceded the onset of movement disorder. During the following 3 months, chorea slowly progressed and became generalized with sparing of the oro-mandibular and facial muscles and he developed mild dystonic posturing of upper limbs. At this stage, diurnal fluctuations of chorea became evident, with increased severity lasting about 2 hours after waking up in the morning (Video 1). Chorea slowly improved during the day, showed no worsening before falling asleep, and was absent at night. Cognitive assessment was normal (total IQ 5 114). Brain MRI performed 2 months after onset of symptoms revealed bilateral symmetrical hyper-intense lesions on T2weighted, FLAIR and diffusion weighted images involving the putamen and caudate nuclei (Fig. 1). An extensive diagnostic workup, including CSF analysis (neurotransmitters, folates), plasma lactate/pyruvate, activity of the respiratory chain enzymes in muscle, basic metabolic panel, and a screening for autoimmune and infectious conditions, was unremarkable. Targeted sequencing of striatal necrosis-related genes yielded negative results. Whole-exome sequencing was performed as previously described and revealed a heterozygous known pathogenic PDE10A missense variant (c.1000T>C, p.Phe334Leu; transcript ENST00000539869). Sanger sequencing confirmed the presence of the variant and segregation analysis in the parents demonstrated it arose de novo in the proband. The patient was started on trihexyphenidyl (1 mg daily), which was discontinued because of behavioral changes. Tetrabenazine was not administered because of the patient’s young age and overall mild severity of chorea. After 2 years of follow-up, chorea showed no progression, but diurnal fluctuations consistently persisted (Video 1) and brain MRI was unchanged. No additional therapies were started. This report confirms the homogeneous phenotype related to dominant PDE10A mutations. The unique clinical presentation of childhood-onset chorea with a scarcely progressive course associated with bilateral striatal lesions is highly suggestive of dominant PDE10A mutations. To date, only 2 recurrent dominant pathogenic variants have been identified (p.Phe300Leu and p.Phe334Leu, each detected in 2 unrelated patients), suggesting that these residues are mutational hotspots. Unlike previously reported PDE10A mutation carriers, our case showed marked diurnal fluctuations with chorea being more severe upon awakening in the morning. Differently from our case, patients with ADCY5-related chorea often show characteristic exacerbations lasting up to hours both upon awakening and falling asleep. Cases with DOPA-responsive dystonia as a result of GCH1 mutations present with marked worsening of symptoms during the day. The pattern of motor fluctuation observed in this case of PDE10A-related chorea may represent an additional clue for the identification of this rare movement disorder.

The absence that makes the difference: choroidal abnormalities in Legius syndrome

Neurofibromatosis type 1 (NF1) is an hereditary disorder characterized by abnormal proliferation of multiple tissues of neural crest origin, and presents mainly with multiple café-au-lait macules, axillary freckling and neurofibromas. Choroidal involvement in NF1 patients has been studied, thanks to the development of non-invasive tools such as infrared monochromatic light during fundus examination, which showed bright patchy lesions consistent with choroidal nodules. Choroidal abnormalities identified with near-infrared reflectance have reported with a frequency of up to 100% in NF1, and have been recently been proposed as a novel diagnostic criterion for NF1. Legius syndrome can be clinically indistinguishable from NF1 and results in a small percentage of individuals being misdiagnosed. We investigated the presence of choroidal abnormalities in Legius syndrome to determine their specificity to NF1 and their potential usefulness as a novel diagnostic criterion for NF1. We examined the fundus of 16 eyes by confocal scanning laser ophthalmoscopy with infrared monochromatic light in eight patients with molecularly confirmed Legius syndrome. No abnormalities were observed, confirming the diagnostic value of choroidal abnormalities for the diagnosis of NF1.