Biallelic variants in NOS3 and GUCY1A3, the two major genes of the nitric oxide pathway, cause moyamoya cerebral angiopathy.

BACKGROUND: Moyamoya angiopathy (MMA) is a rare cerebrovascular condition leading to stroke. Mutations in 15 genes have been identified in Mendelian forms of MMA, but they explain only a very small proportion of cases. Our aim was to investigate the genetic basis of MMA in consanguineous patients having unaffected parents in order to identify genes involved in autosomal recessive MMA. METHODS: Exome sequencing (ES) was performed in 6 consecutive consanguineous probands having MMA of unknown etiology. Functional consequences of variants were assessed using western blot and protein 3D structure analyses. RESULTS: Causative homozygous variants of NOS3, the gene encoding the endothelial nitric oxide synthase (eNOS), and GUCY1A3, the gene encoding the alpha1 subunit of the soluble guanylate cyclase (sGC) which is the major nitric oxide (NO) receptor in the vascular wall, were identified in 3 of the 6 probands. One NOS3 variant (c.1502 + 1G > C) involves a splice donor site causing a premature termination codon and leads to a total lack of eNOS in endothelial progenitor cells of the affected proband. The other NOS3 variant (c.1942 T > C) is a missense variant located into the flavodoxine reductase domain; it is predicted to be destabilizing and shown to be associated with a reduction of eNOS expression. The GUCY1A3 missense variant (c.1778G > A), located in the catalytic domain of the sGC, is predicted to disrupt the tridimensional structure of this domain and to lead to a loss of function of the enzyme. Both NOS3 mutated probands suffered from an infant-onset and severe MMA associated with posterior cerebral artery steno-occlusive lesions. The GUCY1A3 mutated proband presented an adult-onset MMA associated with an early-onset arterial hypertension and a stenosis of the superior mesenteric artery. None of the 3 probands had achalasia. CONCLUSIONS: We show for the first time that biallelic loss of function variants in NOS3 is responsible for MMA and that mutations in NOS3 and GUCY1A3 are causing fifty per cent of MMA in consanguineous patients. These data pinpoint the essential role of the NO pathway in MMA pathophysiology.

Anatomo-functional study of the cerebellum in working memory in children treated for medulloblastoma.

INTRODUCTION: Medulloblastoma is the most common malignant cerebral tumor during childhood, arising in the posterior fossa. Children treated for medulloblastoma often experience working memory (WM) deficits, affecting their quality of life and school performance. The aim of the present study undertaken to describe the cerebellar involvement in WM deficits observed in these children. MATERIAL AND METHODS: 23 healthy children and 11 children treated for medulloblastoma were included into study. All subjects performed a detailed neuropsychological examination, an anatomical and functional MRI. Stimuli were presented to the participants with alternating sensory modality and nature of communication in a block design during functional magnetic resonance imaging acquisitions. Non-parametric tests were used for analyzing neuropsychological and behavioral data. SPM8 and SUIT (Spatially Unbiased Atlas Template) were used for anatomical and functional MRI data analyses. RESULTS: Patients had cerebellar resections mainly located in the left posterior lobe. Patients had significantly reduced intelligence quotient, central executive and visuospatial WM. In healthy children group, fMRI showed activations for non-verbal and visuospatial WM in the left posterior cerebellar lobe. CONCLUSION: This study provides further evidence that left posterior cerebellar lobe plays a critical role in WM. Indeed, lesions of left posterior cerebellar lobe were associated with WM impairment in children treated for cerebellar medulloblastoma. Additionally, fMRI using WM tasks showed activation in the left posterior cerebellar lobe in healthy children. Taken together, these findings may help for improving treatment and rehabilitation of children referred for cerebellar tumor.

Microdeletion del(22)(q12.1) excluding the MN1 gene in a patient with craniofacial anomalies.

Several studies have recently reported that 22q12.1 deletions encompassing the MN1 gene are associated with craniofacial anomalies. These observations are consistent with the hypothesis that MN1 haploinsufficiency may be solely responsible for craniofacial anomalies and/or cleft palate. We report here the case of a 4-year-old boy presenting with global developmental delay and craniofacial anomalies including severe maxillary protrusion and retromicrognathia. Array-CGH detected a 2.4 Mb de novo deletion of chromosome 22q12.1 which did not encompass the MN1 gene thought to be the main pathological candidate in 22q12.1 deletions. This observation, combined with data from other patients from the Database of Chromosomal Imbalance and Phenotype in Humans Using Ensemble Resources (DECIPHER), suggests that other gene(s) in the 22q12.1 region are likely involved in craniofacial anomalies and/or may contribute to the phenotypic variability observed in patients with MN1 deletion.

Voltage-gated potassium channels autoantibodies in a child with rasmussen encephalitis.

Rasmussen encephalitis (RE) is a severe epileptic and inflammatory encephalopathy of unknown etiology, responsible for focal neurological signs and cognitive decline. The current leading hypothesis suggests a sequence of immune reactions induced by an indeterminate factor. This sequence is thought to be responsible for the production of autoantibody-mediated central nervous system degeneration. However, these autoantibodies are not specific to the disease and not all patients present with them. We report the case of a 4-year-old girl suffering from RE displaying some atypical features such as fast evolution and seizures of left parietal onset refractory to several antiepileptics, intravenous immunoglobulins, and corticosteroids. Serum autoantibodies directed against voltage-gated potassium channels (VGKC) were evidenced at 739 pM, a finding never previously reported in children. This screening was performed because of an increased signal in the temporolimbic areas on brain magnetic resonance imaging, which was similar to what is observed during limbic encephalitis. The patient experienced epilepsia partialis continua with progressive right hemiplegia and aphasia. She underwent left hemispherotomy at the age of 5.5 years after which she became seizure free with great cognitive improvement. First described in adults, VGKC autoantibodies have been recently described in children with various neurological manifestations. The implication of VGKC autoantibodies in RE is a new observation and opens up new physiopathological and therapeutic avenues of investigation.

Place of magistral preparations to continue the treatment if the drug is commercially stopped worldwide? A case report of a 10-year-old child with subacute sclerosing panencephalitis (SSPE) requiring inosiplex.

Subacute sclerosing panencephalitis (SSPE) is a late-onset and fatal viral disease caused by persistent infection of the central nervous system by measles virus (MeV). We present the case of a 10-year-old child from South Asia affected by SSPE, stabilized with a combination of intrathecal interferon-α2b (INF-α2b) injections and oral inosiplex and how we continued the treatment when inosiplex was commercially stopped worldwide.

Cognitive disorders in pediatric medulloblastoma: what neuroimaging has to offer.

Medulloblastomas are the most common malignant childhood brain tumors arising in the posterior fossa. Treatment improvements for these tumors have meant that there are a greater number of survivors, but this long-term patient survival has increased the awareness of resulting neurocognitive deficits. Impairments in attention, memory, executive functions, and intelligence quotient demonstrate that the cerebellum likely plays a significant role in numerous higher cognitive functions such as language, cognitive, and emotional functions. In addition, children with medulloblastoma not only have cerebellar lesions but also brain white matter damages due to radiation and chemotherapy. Functional neuroimaging, a noninvasive method with many advantages, has become the standard tool in clinical and cognitive neuroscience research. By reviewing functional neuroimaging studies, this review aims to clarify the role of the cerebellum in cognitive function and explain more clearly cognitive sequelae due to polytherapy in children with medulloblastoma. This review suggests that the posterior cerebellar lobes are crucial to maintaining cognitive performance. Clinical investigations could help to better assess the involvement of these lobes in cognitive functions.

Clustering syncope in a young male with temporal lobe seizures.

We report the case of a male aged 2 years 6 months with left temporal lobe epilepsy who presented with ictal bradycardia syndrome leading to asystole. The clinical presentation was remarkable for the occurrence of clustering syncope. A seizure was recorded on a video electroencephalogram- electrocardiogram and analyzed. A cardiac pacemaker was implanted and antiepileptic drug treatment was initiated. We suggest that clustering of syncope is an important feature in the presentation of epilepsy in a young child.