Chromatin remodeling complexes are known to modify chemical marks on histones or to induce conformational changes in the chromatin in order to regulate transcription. De novo dominant mutations in different members of the SWI/SNF chromatin remodeling complex have recently been described in individuals with Coffin-Siris (CSS) and Nicolaides-Baraitser (NCBRS) syndromes. Using a combination of whole-exome sequencing, NGS-based sequencing of 23 SWI/SNF complex genes, and molecular karyotyping in 46 previously undescribed individuals with CSS and NCBRS, we identified a de novo 1-bp deletion (c.677delG, p.Gly226Glufs*53) and a de novo missense mutation (c.914G>T, p.Cys305Phe) in PHF6 in two individuals diagnosed with CSS. PHF6 interacts with the nucleosome remodeling and deacetylation (NuRD) complex implicating dysfunction of a second chromatin remodeling complex in the pathogenesis of CSS-like phenotypes. Altogether, we identified mutations in 60% of the studied individuals (28/46), located in the genes ARID1A, ARID1B, SMARCB1, SMARCE1, SMARCA2, and PHF6. We show that mutations in ARID1B are the main cause of CSS, accounting for 76% of identified mutations. ARID1B and SMARCB1 mutations were also found in individuals with the initial diagnosis of NCBRS. These individuals apparently belong to a small subset who display an intermediate CSS/NCBRS phenotype. Our proposed genotype-phenotype correlations are important for molecular screening strategies.

Schwannomatosis (MIM 162091) is a condition predisposing to the development of central and peripheral schwannomas; most cases are sporadic without a clear family history but a few families with a clear autosomal dominant pattern of transmission have been described. Germline mutations in SMARCB1 are associated with schwannomatosis. We report a family with multiple schwannomas and meningiomas. A SMARCB1 germline mutation in exon 1 was identified. The mutation, c.92A>T (p.Glu31Val), occurs in a highly conserved amino acid in the SMARCB1 protein. In addition, in silico analysis demonstrated that the mutation disrupts the donor consensus sequence of exon 1. RNA studies verified the absence of mRNA transcribed by the mutant allele. This is the first report of a SMARCB1 germline mutation in a family with schwannomatosis characterized by the development of multiple meningiomas.

Neurofibromatosis 1 is the most common neurocutaneous disease. Neurologic manifestations are mainly represented by tumors such as optic gliomas, focal areas of high T2-weighted signal known as unidentified bright objects, and mental retardation or learning disabilities. The prevalence of seizures has been reported to range from 3.8 to 6%. In the present study, we evaluated prevalence, type, and etiology of epilepsy in a neurofibromatosis 1 population. A retrospective analysis of 198 patients affected by neurofibromatosis 1 was performed. Fourteen patients (7%) were found to be epileptic. Every patient underwent electroencephalographic examination and neuroimaging investigations. Thirteen were submitted to magnetic resonance imaging (MRI) study and one to computed tomographic (CT) scanning. Single-photon emission computed tomographic and positron emission tomographic studies were performed in a few selected cases. Seizures were partial in 12 of these (85%) and generalized in 2 (15%). In nine (64%), epilepsy was secondary to brain lesions: five of these had cerebral tumors (three with epilepsy as the fist symptom), three had cortical malformation, and one had mesial temporal sclerosis. Seizures were controlled rapidly in eight (57%) and drug resistant in four (29%). Two patients were lost at follow-up. All patients with uncontrolled seizures had severe mental retardation, and three of these had malformations of cortical development. Our observations and our re-evaluation of the literature indicate that patients with neurofibromatosis 1 have an increased risk of epilepsy related to intracranial masses and cytoarchitectural abnormalities, and seizures can represent the first symptom of a tumor or cortical malformation. Brain MRI and, in selected cases, functional studies appear to be useful in patients with neurofibromatosis 1 who present with seizures, especially if associated with mental retardation.

The molecular and antigenic properties of a Sabin-like type 2 poliovirus, isolated from the stool samples of a 2-year-old agammaglobulinaemic child who developed paralysis 1 year after receiving the third dose of oral poliovirus vaccine, were analysed. The virus revealed 0?88 % genome variation in the VP1 region compared with the standard reference strain, compatible with replication of the virus in the intestine over approximately 1 year. The typical mutations in the 59NCR and VP1 associated with reversion to neurovirulence for Sabin type 2 poliovirus were found. Despite this, the virus was characterized by both PCR and ELISA tests as Sabin-like and showed temperature sensitivity and neurovirulence in transgenic mice typical of the Sabin type 2 vaccine strain. Gammaglobulin replacement therapy led rapidly to virus clearance, which, when combined with treatment with the antiviral drug pleconaril, stopped virus excretion; no further virus shedding occurred. This is the first case of poliomyelitis and long-term excretion from an immunodeficient patient to be reported in Italy through the active 'Acute Flaccid Paralysis' surveillance system.

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