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Kawamata H.,Cornell University | Tiranti V.,Irccs Foundation Neurological Institute C Besta | Magrane J.,Cornell University | Chinopoulos C.,Semmelweis University | Manfredi G.,Cornell University
Human Molecular Genetics | Year: 2011

Mutations in the heart and muscle isoform of adenine nucleotide translocator 1 (ANT1) are associated with autosomal-dominant progressive external opthalmoplegia (adPEO) clinically characterized by exercise intolerance, ptosis and muscle weakness. The pathogenic mechanisms underlying the mitochondrial myopathy caused by ANT1 mutations remain largely unknown. In yeast, expression of ANT1 carrying mutations corresponding to the human adPEO ones causes a wide range of mitochondrial abnormalities. However, functional studies of ANT1 mutations in mammalian cells are lacking, because they have been hindered by the fact that ANT1 expression leads to apoptotic cell death in commonly utilized replicating cell lines. Here, we successfully express functional ANT1 in differentiated mouse myotubes, which naturally contain high levels of ANT1, without causing cell death. We demonstrate, for the first time in these disease-relevant mammalian cells, that mutant human ANT1 causes dominant mitochondrial defects characterized by decreased ADP-ATP exchange function and abnormal translocator reversal potential. These abnormalities are not due to ANT1 loss of function, because knocking down Ant1 in myotubes causes functional changes different from ANT1 mutants. Under certain physiological conditions, mitochondria consume ATP to maintain membrane potential by reversing the ADP-ATP transport. The modified properties of mutant ANT1 can be responsible for disease pathogenesis in adPEO, because exchange reversal occurring at higher than normal membrane potential can cause excessive energy depletion and nucleotide imbalance in ANT1 mutant muscle cells. © The Author 2011. Published by Oxford University Press. All rights reserved.

Ragona F.,Irccs Foundation Neurological Institute C Besta
Epilepsia | Year: 2011

Slowing of cognitive skills represents one of the diagnostic criteria of Dravet syndrome. This Italian multicentric study aims at clarifying the roles of epilepsy and/or underlying genetic alteration in determining the cognitive outcome. The study includes infants that were either in follow-up (retrospective study: 26 cases) and newly diagnosed (prospective study: in progress). Our multicentric study shows that slowing of cognitive achievements becomes evident during the second year of life in all cases, and that the epilepsy phenotype indeed has a prognostic value. In this study the early appearance of absences and myoclonic seizures is associated with the worst cognitive outcome; whereas convulsive prolonged seizures do not seem to represent, per se, a bad prognostic factor for mental outcome. In this study, statistical analysis failed to reveal differences in the cognitive outcome with regard to the presence and type of SCN1A mutation. © Wiley Periodicals, Inc. 2011 International League Against Epilepsy.

Granata T.,Irccs Foundation Neurological Institute C Besta
Epilepsia | Year: 2011

The comprehensive care of a patient with Dravet syndrome encompasses both the "care" and the "cure" of the patient, and requires cooperation among family, doctors, and several other specialized caregivers to search for the attainment of the best quality of life for the patients and their families. Several issues peculiar to the disease to be faced while dealing with the patient are: (1) SMEI is an "evolving" disease that appears in an otherwise healthy child with symptoms that appear and mutate throughout the course of the disease; (2) the severity of the disease is not fully predictable at onset and appears to be individual-specific; (3) the seizures are invariably drug resistant and seizure freedom is not a realistic goal; and (4) in addition to seizures many other invalidating clinical problems, including cognitive impairment, behavior disorders, and a number of comorbidities characterize the disease course. The comprehensive caring must be physician-guided and patient-centered and implies a multidisciplinary approach to be built around the children and caregivers, who need to be guided through the steps of the diagnosis, treatments, and managements of the various comorbidities. © Wiley Periodicals, Inc. 2011 International League Against Epilepsy.

Granata T.,Irccs Foundation Neurological Institute C Besta | Valentini L.G.,Irccs Foundation Neurological Institute C Besta
Neurological Sciences | Year: 2011

In patients with Chiari malformation type 1 (CMI), epileptic seizures are occasionally reported both in symptomatic patients candidate to surgery and in patients without symptoms of tonsillar displacement in whom CM1 is often an incidental finding in the diagnostic work up for idiopathic epilepsies. In both groups of patients, the course of epilepsy is almost invariably favorable, with a few seizures easily controlled by treatment. In a subset of CM1 patients, epilepsy occurs in the context of neurodevelopmental disorders that also include mental retardation, autism and somatic dysmorphisms. Epileptic seizures must be accurately differentiated by potentially harmful paroxysmal events due to compression of the medulla, particularly by the cerebellar fits characterized by drop attacks, abnormal extensor posturing and apnea. © Springer-Verlag 2011.

Colombo N.,Ospedale Ca Granda Niguarda | Tassi L.,Claudio Munari Epilepsy Surgery Center | Deleo F.,Irccs Foundation Neurological Institute C Besta | Citterio A.,Ospedale Ca Granda Niguarda | And 6 more authors.
Neuroradiology | Year: 2012

Introduction: This study aims to review the magnetic resonance imaging (MRI) aspects of a large series of patients with focal cortical dysplasia type II (FCD II) and attempt to identify distinctive features in the two histopathological subtypes IIa and IIb. Methods: We retrospectively reviewed the MRI scans of 118 patients with histological proven FCD IIa (n∈=∈37) or IIb (n∈=∈81) who were surgically treated for intractable epilepsy. Results: MRI was abnormal in 93 patients (79 %) and unremarkable in 25 (21 %). A dysplastic lesion was identified in 90 cases (97 %) and classified as FCD II in 83 and FCD non-II in seven cases. In three cases, the MRI diagnosis was other than FCD. There was a significant association between the presence of cortical thickening (p∈=∈0.002) and the transmantle sign (p∈<∈0. 001) and a correct MRI diagnosis of FCD II. MRI positivity was more frequent in the patients with FCD IIb than in those with FCD IIa (91 % vs. 51 %), and the detection rate of FCD II was also better in the patients with type IIb (88 % vs. 32 %). The transmantle sign was significantly more frequent in the IIb subgroup (p∈=∈0.003). Conclusions: The rates of abnormal MRI results and correct MRI diagnoses of FCD II were significantly higher in the IIb subgroup. Although other MRI stigmata may contribute to the diagnosis, the only significant correlation was between the transmantle sign and FCD IIb. © 2012 Springer-Verlag.

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