Rossella Vivarelli

Schwannomatosis associated with multiple meningiomas due to a familial SMARCB1 mutation

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.

Epilepsy in Neurofibromatosis 1

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 first 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. (J Child Neurol 2003;18:338—342).

Efficacy and safety of topiramate in infants according to epilepsy syndromes

Studies of the efficacy of topiramate (TPM) in infants and young children are few. Here we report an open, prospective, and pragmatic study of effectiveness of TPM in terms of epilepsy syndromes, in children aged less than 2 years. The median follow-up period was 11 months. We enrolled 59 children in the study: 22 affected by localization-related epilepsy (LRE), 23 by generalized epilepsy, six by Dravets syndrome, and eight with unclassifiable epilepsy. TPM was effective (responders showed a decrease of more than 50% in seizure frequency) in 47% of patients, including 13% who were seizure-free at the last visit. TPM was more effective in localization-related epilepsy (48% of responders) than in generalized epilepsy (32% of responders). In the latter group, 19 patients suffered from infantile spasms. Four of six patients with cryptogenic infantile spasms became seizure-free. Of the 13 patients with symptomatic infantile spasms, only one was seizure-free. Results were poor for patients with Dravets syndrome. In general, TPM was well tolerated. The most frequently reported adverse effects were drowsiness, irritability, hyperthermia, and anorexia. The present study concludes that TPM is effective for a broad range of seizures in infants and young children and represents a valid therapeutic option in this population.

GM2 gangliosidosis variant B1 neuroradiological findings.

Abstract. Variant B1 is a rare type of GM2 gangliosidosis. Clinically, it shows a wide spectrum of forms ranging from infantile to juvenile. We report the first magnetic resonance imaging (MRI) findings from three patients affected by GM2 gangliosidosis variant B1, two presenting with the infantile form and one with the juvenile form. The MRI appearances of the two patients with the infantile form disease are congruent with those reported for the early-onset type of both Tay-Sachs and Sandhoff diseases, and are characterized by early involvement of the basal ganglia and thalamus with cortical atrophy appearing later. In contrast, the patient with the juvenile form of variant B1 showed progressive cortical and white-matter atrophy of the supratentorial structures and, to a lesser extent, the infratentorial structures. No basal ganglia or thalamic anomalies were observed. Because in the adult forms of both Tay-Sachs and Sandhoff diseases a progressive cerebellar atrophy represents the only abnormality detectable, it appears that an MRI pattern peculiar to GM2 gangliosidosis can be defined. This pattern ranges from the basal ganglia injury associated with the early and severe demyelination process noted in the infantile form of the disease, to cerebellar atrophy with no supratentorial anomalies in the adult form. An “intermediate” MRI picture, with cortical atrophy and mild cerebellar atrophy, but without basal ganglia impairment, can be observed in the juvenile form. In addition, our investigations suggest that MRI abnormalities in GM2 gangliosidosis correlate with the clinical form of the disease rather than with the biochemical variant of the enzymatic defect.

Pseudo-TORCH syndrome or Baraitser–Reardon syndrome: diagnostic criteria

Intracranial calcification and microcephaly, which represent the main clinical features of the TORCH-syndrome, can also be determined by a rare autosomal recessive infection-like condition named pseudo-TORCH syndrome. This emerging entity has been registered in eight families so far. We report on five patients from three unrelated Italian families affected by pseudo-TORCH syndrome. Reevaluation of literature allowed us to draw a specific clinical profile of the syndrome. Indeed, congenital microcephaly, congenital cerebral calcification, spasticity and seizures are the main clinical features, and have been present in almost all patients reported so far. On the contrary, findings resembling congenital infectious diseases including neonatal icterus, hyperbilirubinemia, thrombocytopenia, and hepatomegaly, affect less than half of the patients. Considering the diagnosis of pseudo-TORCH syndrome in patients with neonatal microcephaly and cerebral calcification is necessary since an early diagnosis may allow adequate genetic counseling to the families.

Central nervous system imaging in reevaluation of patients with neurofibromatosis type 1

We report the results of the reevaluation of 24 patients with neurofibromatosis type 1 (NF1) using central nervous system (CNS) imaging techniques. The first examination by computed tomography (CT) or magnetic resonance imaging (MRI) indicated the presence of optic glioma in three cases, “unidentified bright objects” (UBOs) in six, and a suspected right frontal tumor in one. In two patients optic glioma and UBOs were both present and in one of them a bulbar tumor was also suspected. Later imaging examinations revealed the appearance of optic glioma in three more cases and UBOs in nine. In two of these patients both optic glioma and UBOs were present. This study indicates that the likelihood of detecting imaging abnormalities in patients with NF1 increases when systematic follow-up is performed. Optic gliomas are characteristic of pediatric patients; they rarely give rise to clinical manifestations (1/6 cases) and in general progress very slowly. For these reasons, therapeutic strategy must be carefully considered and individually decided. UBOs are very frequent findings in pediatric patients with NF 1 and therefore they must be considered diagnostically relevant. They are not related to clinical manifestations and spontaneous regression has been observed. The nature of these imaging abnormalities is still unknown, but because they do not behave like tumors, useless and dangerous therapeutic procedures should not be employed.

Chromosome abnormalities in tuberous sclerosis

SummaryIn fibroblasts cultured from biopsies of the skin lesions of six patients with tuberous sclerosis (TS) there was a variable but consistent degree of karyotypic variation. Premature centromere disjunction (PCD) of all or part of the chromosomes, micronuclei, an increased incidence of breaks, dicentric chromosomes and the presence of polyploid metaphases were found in all cultures. The PCD was of the type encountered in Roberts syndrome and its frequency varied from 8% to 30%. In metaphases with PCD of one and of two chromosomes, the chromosome involved were identified, and chromosome 3 was involved 21 times among 59 chromosomes with PCD. Chromosome 3 tends to be preferentially involved in dicentric formation. In lymphocyte cultures from the same patients there were no metaphases with PCD, but there was a slight increase of breaks and the presence of dicentric chromosomes, also involving chromosome 3. Polyploid metaphases were increased in some of the cases. Karyotypic variation can be considered a cellular phenotypic characteristic of TS in fibroblasts cultured from the skin lesions, and its type indicates disturbances in the mechanics of centromere division and of chromosome distribution at cell division.

Coffin-Siris and Nicolaides-Baraitser syndromes are a common well recognizable cause of intellectual disability.

BACKGROUND Nicolaides-Baraitser and Coffin-Siris syndromes are emerging conditions with overlapping clinical features including intellectual disability and typical somatic characteristics, especially sparse hair, low frontal hairline, large mouth with thick and everted lips, and hands and feet anomalies. Since 2012, mutations in genes encoding six proteins of the BAF complex were identified in both conditions. METHODS AND RESULTS We have clinically evaluated a cohort of 1161 patients with intellectual disability from three different Italian centers. A strong clinical suspicion of either Nicolaides-Baraitser syndrome or Coffin-Siris syndrome was proposed in 11 cases who were then molecularly confirmed: 8 having de novo missense mutations in SMARCA2, two frame-shift mutations in ARID1B and one missense mutation in SMARCB1. Given the high frequency of the condition we set up a one-step deep sequencing test for all 6 genes of the BAF complex. CONCLUSIONS These results prove that the frequency of these conditions may be as high as the most common syndromes with intellectual deficit (about 1%). Clinical geneticists should be well aware of this group of disorders in the clinical setting when ascertaining patients with intellectual deficit, the specific facial features being the major diagnostic handle. Finally, this work adds information on the clinical differences of the two conditions and presents a fast and sensitive test for the molecular diagnosis.

Quantitative Ultrasound and Dual-Energy X-ray Absorptiometry in Children and Adolescents With Neurofibromatosis of Type 1

Reduced areal bone mineral density (aBMD) is a common feature of neurofibromatosis type 1 (NF1). Moreover, in recent years there has been a growing interest in using quantitative ultrasound (QUS) for the evaluation of bone status. In 55 NF1 subjects (mean age: 9.3+/-5.4yr) and in 51 age- and sex-matched controls we measured aBMD at lumbar spine, at femoral neck (aBMD-FN), and at total femur (aBMD-T). Apparent volumetric bone mineral density (BMAD) was also calculated. In all subjects, QUS parameters at phalanges were evaluated. In NF1 subjects, the values of aBMD and BMAD were lower than in controls at all skeletal sites, but the difference reached statistical significance only at femoral sites (p<0.05). Both aBMD and QUS parameters were lower in those NF1 subjects with skeletal abnormalities than in those without abnormalities, but the difference was statistically significant (p<0.05) only for aBMD-FN and aBMD-T. Multiple regression analysis showed that the subjects with skeletal abnormalities had a higher risk of having bone transmission time (BTT) Z-score and aBMD Z-score at femoral sites less than -1. In conclusion, our results suggest that aBMD and QUS represent useful tools in evaluating the impairment of bone status in NF1 subjects.

Late-onset childhood occipital epilepsy (Gastaut type): A family study

Late onset childhood occipital epilepsy-Gastaut type (LOCOE) is a rare idiopathic epilepsy syndrome with an uncertain long-term prognosis. Elementary visual hallucinations and interictal spike-and-wave complexes in the occipital areas represent the main electroclinical findings of the syndrome. The functional nature of LOCOE has been emphasized together with the presence of genetic predisposition in the affected patients. Here, we report on two families in which two patients, respectively, showed electroclinical features compatible with LOCOE. Although further studies are needed to validate our observations, the involvement of two generations in one of the families we studied may corroborate the previously formulated hypothesis of an autosomal dominant model of inheritance in LOCOE. Of course, the identification of larger families is propaedeutic to linkage analysis studies.