Sabrina Buoni

FOXG1 Is Responsible for the Congenital Variant of Rett Syndrome

Rett syndrome is a severe neurodevelopmental disease caused by mutations in the X-linked gene encoding for the methyl-CpG-binding protein MeCP2. Here, we report the identification of FOXG1-truncating mutations in two patients affected by the congenital variant of Rett syndrome. FOXG1 encodes a brain-specific transcriptional repressor that is essential for early development of the telencephalon. Molecular analysis revealed that Foxg1 might also share common molecular mechanisms with MeCP2 during neuronal development, exhibiting partially overlapping expression domain in postnatal cortex and neuronal subnuclear localization.

Novel PTEN mutations in neurodevelopmental disorders and macrocephaly.

Somatic mutations of the phosphatase and tensin (PTEN) gene have been frequently detected in many types of human cancer. However, germline mutations can determine multiple hamartoma syndromes and, as more recently ascertained, syndromes clinically characterized by autism associated with macrocephaly. To determine whether germline mutations of PTEN may lead to different phenotypes, we screened all the nine exons of the PTEN gene in 40 patients with neurodevelopmental disorders, with or without features of autism spectrum disorder, associated with macrocephaly. Three novel de novo missense mutations were found (p.H118P, p.Y176C, p.N276S) in two severely mentally retarded patients with autism and in a subject with neurodevelopmental disorders without autistic features. Our results provide evidence that PTEN germline mutations may sustain a more wide phenotypical spectrum than previously suggested.

Telomere length and obesity.

Aim: To assess the telomere length in apparently healthy obese and normal‐weight subjects.

Vagus nerve stimulation for drug-resistant epilepsy in children and young adults

We present our experience with the use of intermittent vagal nerve stimulation in 13 patients with medically intractable epilepsy. A surgical approach, with the exception of callosotomy, was impossible. The age range was 6-28 years (median 17 years). In all patients the epilepsy was severe and in six of them was symptomatic. Seven patients had Lennox-Gastaut syndrome, one epilepsy with myoclonic-astatic seizures, four localization-related and one symptomatic generalized epilepsy. The length of the follow-up averaged 22 months (range 8 months-3 years). Of the 13 patients, five (38.4%) had a 50% or more reduction in the number of seizures compared with preimplantation. Of these patients, one with a localization-related epilepsy had a 90% reduction as well as a significant improvement in alertness. Three patients showed no improvement with regard to the number of seizures but there was an improvement in alertness and, in one case in hyperactivity. Some seizure types responded better than others did: complex partial seizures with secondary generalization and atonic seizures. All our responsive patients improved in the first 2 months of VNS activation and only one case with further improvement was observed after this period. Considering the severity of the epilepsy the results can be considered satisfactory. We think that this treatment appears to be a safe adjunctive therapy for children and adults with medically and surgically intractable epilepsy.

Diagnosis of Angelman syndrome: clinical and EEG criteria

In order to evaluate which diagnostic criteria can be indicative for an early diagnosis of Angelman syndrome (AS), 144 children with severe epilepsy and mental retardation were evaluated. In 10 of them the diagnostic criteria indicated by Williams were present. Of the remaining 134 patients we were able to diagnose one 15-year-old patient with AS, on the basis of the EEG findings, even though the typical clinical features of the syndrome were absent. In all patients the diagnosis of AS was confirmed by fluorescent in situ hybridization (FISH) in 10 patients and by methylation analysis in one patient. AS is very likely when both typical clinical and EEG findings are present. Nevertheless, it must be considered in all patients affected by severe epilepsy and mental retardation, when the EEG pattern is sufficiently indicative, and FISH and/or molecular analysis should be performed even in absence of typical clinical signs.

Epilepsy in Rett syndrome: clinical and genetic features.

Epilepsy often occurs in Rett syndrome and is considered a major problem. The aim of this study was to define the clinical features of epilepsy and the correlation between seizures and both genotype and clinical phenotype in the Rett population. One hundred sixty-five patients with Rett syndrome referred to four Italian centers were recruited. All patients underwent video/EEG monitoring and molecular analysis of the MECP2 gene or, in negative cases, of the CDKL5 and FOXG1 genes. The frequency of epilepsy was 79%. Drug-resistant epilepsy occurred in 30% of all our patients with Rett syndrome and in 38% of those with epilepsy. Our findings demonstrate that epilepsy differs among the various phenotypes and genotypes with respect to age at onset, drug responsiveness, and seizure semiology. The Hanefeld and preserved speech variants represent the extremes of the range of severity of epilepsy: the preserved speech variant is characterized by the mildest epileptic phenotype as epilepsy is much less frequent, starts later, and is less drug resistant than what is observed in the other phenotypes. Another important finding is that seizure onset before 1 year of age and daily frequency are risk factors for drug resistance. Thus, this study should help clinicians provide better clinical counseling to the families of patients with Rett syndrome.

A randomized trial of oral betamethasone to reduce ataxia symptoms in ataxia telangiectasia.

No controlled studies exist regarding the pharmaceutical reduction of ataxia symptoms in ataxia telangiectasia (A‐T). In a multicenter, double‐blind, randomized, placebo‐controlled crossover trial, oral betamethasone (BETA) and placebo were compared in terms of their reduction of ataxia symptoms as assessed with the International Cooperative Ataxia Rating Scale (ICARS). In this study of 13 A‐T children, betamethasone reduced the ICARS total score by a median of 13 points in the intent‐to‐treat population and 16 points in the per‐protocol population (ie, median percent decreases of ataxia symptoms of 28% and 31%, respectively). In conclusion, Oral betamethasone could be a promising therapy to relieve ataxia symptoms in A‐T patients; however, long‐term effectiveness and safety must be established. (Current Controlled Trials, number ISRCTN08774933.)

Hemimegalencephaly in Tuberous Sclerosis Complex

The purpose of this case report is to describe the computed tomographic and magnetic resonance imaging findings of the brain of a 16-month-old girl with an uncommon association between hemimegalencephaly and tuberous sclerosis complex. When a large calcification is found within a hemimegalencephalic cerebral hemisphere, further investigation of a suspected associated tuberous sclerosis complex or another phakomatosis is required to determine pertinent treatment options and genetic counseling. (J Child Neurol 2002;17:677-680).

Lamotrigine in typical absence epilepsy

Lamotrigine (LTG) is an anti-epileptic drug effective in partial seizures and generalized epilepsy. There is growing evidence of the usefulness of LTG in childhood (CAE) orjuvenile (JAE) absences resistant to previous treatment. In this study all patients were identified using strict diagnostic criteria and subdivided into two groups. (1) Eight patients affected by absence seizures resistant to valproic acid or ethosuximide, received LTG as an-add-on therapy, (2) seven patients affected by typical absence seizures not previously treated, received LTG monotherapy after the diagnosis. In the patients with resistant absence seizures, a full control of seizures was obtained. In five of them, after a mean period of 12.5 months, the previous anti-epileptic drugs were withdrawn leaving the patients on LTG monotherapy. In one patient, absences relapsed and valproic acid was therefore added again to LTG to regain control of the seizures. In six of the seven patients on LTG monotherapy after the diagnosis, a full control of seizures was obtained. In the seventh patient the drug was stopped due to a skin rash. In conclusion LTG appears to be effective in resistant absence seizures in combination with valproic acid. Moreover, our preliminary data suggest that lamotrigine might be used as monotherapy in typical absence seizures. The advantages and disadvantages of LTG monotherapy in this type of epilepsy are discussed.

Widening the Mutation Spectrum of EVC and EVC2: Ectopic Expression of Weyer Variants in NIH 3T3 Fibroblasts Disrupts Hedgehog Signaling

Autosomal recessive Ellis‐van Creveld syndrome and autosomal dominant Weyer acrodental dysostosis are allelic conditions caused by mutations in EVC or EVC2. We performed a mutation screening study in 36 EvC cases and 3 cases of Weyer acrodental dysostosis, and identified pathogenic changes either in EVC or in EVC2 in all cases. We detected 40 independent EVC/EVC2 mutations of which 29 were novel changes in Ellis‐van Creveld cases and 2 were novel mutations identified in Weyer pedigrees. Of interest one EvC patient had a T>G nucleotide substitution in intron 7 of EVC (c.940−150T>G), which creates a new donor splice site and results in the inclusion of a new exon. The T>G substitution is at nucleotide +5 of the novel 5′ splice site. The three Weyer mutations occurred in the final exon of EVC2 (exon 22), suggesting that specific residues encoded by this exon are a key part of the protein. Using murine versions of EVC2 exon 22 mutations we demonstrate that the expression of a Weyer variant, but not the expression of a truncated protein that mimics an Ellis‐van Creveld syndrome mutation, impairs Hedgehog signal transduction in NIH 3T3 cells in keeping with its dominant effect. Hum Mutat 30:1–9, 2009.