Neurogenetics Unit

Santa Margherita di Belice, Italy

Neurogenetics Unit

Santa Margherita di Belice, Italy
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Dravet C.,Center Saint Paul Hopital Henri Gastaut | Dravet C.,Neurogenetics Unit
Epilepsia | Year: 2011

Dravet syndrome was described in 1978 by Dravet (1978) under the name of severe myoclonic epilepsy in infancy (SMEI). The characteristics of the syndrome were confirmed and further delineated by other authors over the years. According to the semiologic features, two forms have been individualized: (1) the typical, core, SMEI; and (2) the borderline form, SMEIB, in which the myoclonic component is absent or subtle. Clinical manifestations at the onset, at the steady state, and during the course of the disease are analyzed in detail for the typical Dravet syndrome, and the differential diagnosis is discussed. Onset in the first year of life by febrile or afebrile clonic and tonic-clonic, generalized, and unilateral seizures, often prolonged, in an apparently normal infant is the first symptom, suggesting the diagnosis. Later on, multiple seizure types, mainly myoclonic, atypical absences, and focal seizures appear, as well as a slowing of developmental and cognitive skills, and the appearance of behavioral disorders. Mutation screening for the SCN1A gene confirms the diagnosis in 70-80% of patients. All seizure types are pharmacoresistent, but a trend toward less severe epilepsy and cognitive impairment is usually observed after the age of 5 years. © Wiley Periodicals, Inc. 2011 International League Against Epilepsy.

PubMed | University of Rome La Sapienza, Neurogenetics Unit, IRCCS Neuromed Institute and University of Bari
Type: | Journal: Experimental brain research | Year: 2016

Gilles de la Tourette syndrome (GTS) is characterized by motor and vocal tics and often associated with obsessive-compulsive disorder (OCD). Responses to intermittent/continuous theta-burst stimulation (iTBS/cTBS), which probe long-term potentiation (LTP)-/depression (LTD)-like plasticity in the primary motor cortex (M1), are reduced in GTS. ITBS-/cTBS-induced M1 plasticity can be affected by brain-derived neurotrophic factor (BDNF) polymorphism. We investigated whether the BDNF polymorphism influences iTBS-/cTBS-induced LTP-/LTD-like M1 plasticity in 50 GTS patients and in 50 age- and sex-matched healthy subjects. In GTS patients, motor and psychiatric (OCD) symptom severity was rated using the Yale Global Tic Severity Scale (YGTSS) and the Yale-Brown Obsessive-Compulsive Scale (Y-BOCS). We compared M1 iTBS-/cTBS-induced plasticity in healthy subjects and in patients with GTS. We also compared responses to TBS according to BDNF polymorphism (Val/Val vs Met carriers) in patients and controls. Fourteen healthy subjects and 13 GTS patients were Met carriers. When considering the whole group of controls, as expected, iTBS increased whereas cTBS decreased MEPs. Differently, iTBS/cTBS failed to induce LTP-/LTD-like plasticity in patients with GTS. When comparing responses to TBS according to BDNF polymorphism, in healthy subjects, Met carriers showed reduced MEP changes compared with Val/Val individuals. Conversely, in patients with GTS, responses to iTBS/cTBS were comparable in Val/Val individuals and Met carriers. YGTSS and Y-BOCS scores were comparable in Met carriers and in Val/Val subjects. We conclude that iTBS and cTBS failed to induce LTP-/LTD-like plasticity in patients with GTS, and this was not affected by BDNF genotype.

Squitieri F.,Neurogenetics Unit | Falleni A.,University of Pisa | Cannella M.,Neurogenetics Unit | Orobello S.,Neurogenetics Unit | And 4 more authors.
Journal of Neural Transmission | Year: 2010

We investigated the genotype-dependency of morphological abnormalities in peripheral cells from Huntington disease (HD) patients. Cell cultures derived from skin and muscle biopsies showed a different set of abnormalities depending on the genotype (i.e. heterozygous and homozygous for CAG mutations) and the tissue (i.e. fibroblasts and myoblasts). In general, homozygotes' cell lines showed massive ultrastructural damage of specific cell organelles compared with age matched control. These consist of vacuolization, deranged crests and matrix found within giant mitochondria. In addition, enlarged endoplasmic reticulum and the occurrence of numerous autophagic vacuoles, which were similar to those occurring in neurons within affected brain areas, were described. Despite a comparable dose-dependency on mitochondrial changes, this kind of alterations differ in fibroblasts compared with myoblasts. In fact, the internal mitochondrial structure was merely lost in myoblasts, while it shows pathological re-organization within fibroblasts, where altered crests appear as multilamellar circles. These data indicate that ultrastructural abnormalities from peripheral tissues of HD patients can be used as potential disease markers which are easier to get than autoptic brains. Moreover, the occurrence of ultrastructural cell pathology reminiscent of neuronal degeneration in HD, suggests the use of human peripheral cells as a tool to investigate the pathogenic cascade subsequent to huntingtin dysregulation. © 2009 Springer-Verlag.

PubMed | Neurogenetics Unit, Simon Fraser University, Reims University Hospital Center, University College Dublin and 3 more.
Type: Journal Article | Journal: PLoS biology | Year: 2016

Cilia have a unique diffusion barrier (gate) within their proximal region, termed transition zone (TZ), that compartmentalises signalling proteins within the organelle. The TZ is known to harbour two functional modules/complexes (Meckel syndrome [MKS] and Nephronophthisis [NPHP]) defined by genetic interaction, interdependent protein localisation (hierarchy), and proteomic studies. However, the composition and molecular organisation of these modules and their links to human ciliary disease are not completely understood. Here, we reveal Caenorhabditis elegans CEP-290 (mammalian Cep290/Mks4/Nphp6 orthologue) as a central assembly factor that is specific for established MKS module components and depends on the coiled coil region of MKS-5 (Rpgrip1L/Rpgrip1) for TZ localisation. Consistent with a critical role in ciliary gate function, CEP-290 prevents inappropriate entry of membrane-associated proteins into cilia and keeps ARL-13 (Arl13b) from leaking out of cilia via the TZ. We identify a novel MKS module component, TMEM-218 (Tmem218), that requires CEP-290 and other MKS module components for TZ localisation and functions together with the NPHP module to facilitate ciliogenesis. We show that TZ localisation of TMEM-138 (Tmem138) and CDKL-1 (Cdkl1/Cdkl2/Cdkl3/Cdlk4 related), not previously linked to a specific TZ module, similarly depends on CEP-290; surprisingly, neither TMEM-138 or CDKL-1 exhibit interdependent localisation or genetic interactions with core MKS or NPHP module components, suggesting they are part of a distinct, CEP-290-associated module. Lastly, we show that families presenting with Oral-Facial-Digital syndrome type 6 (OFD6) have likely pathogenic mutations in CEP-290-dependent TZ proteins, namely Tmem17, Tmem138, and Tmem231. Notably, patient fibroblasts harbouring mutated Tmem17, a protein not yet ciliopathy-associated, display ciliogenesis defects. Together, our findings expand the repertoire of MKS module-associated proteins--including the previously uncharacterised mammalian Tmem80--and suggest an MKS-5 and CEP-290-dependent assembly pathway for building a functional TZ.

Petrucci S.,Neurogenetics Unit | Petrucci S.,University of Rome La Sapienza | Consoli F.,Neurogenetics Unit | Valente E.M.,Neurogenetics Unit | Valente E.M.,University of Salerno
Current Molecular Medicine | Year: 2014

Parkinson Disease (PD) is a common neurodegenerative disorder of intricate etiology, caused by progressive loss of aminergic neurons and accumulation of Lewy bodies. The predominant role of genetics in the etiology of the disease has emerged since the identification of the first pathogenetic mutation in SNCA (alpha-synuclein) gene, back in 1997. Mendelian parkinsonisms, a minority among all PD forms, have been deeply investigated, with 19 loci identified. More recently, genome wide association studies have provided convincing evidence that variants in some of these genes, as well as in other genes, may confer an increased risk for late onset, sporadic PD. Moreover, the finding that heterozygous mutations in the GBA gene (mutated in Gaucher disease) are among the strongest genetic susceptibility factors for PD, has widened the scenario of PD genetic background to enclose a number of genes previously associated to distinct disorders, such as genes causative of spinocerebellar ataxias, mitochondrial disorders and fragile X syndrome. At present, the genetic basis of PD defines a continuum from purely mendelian forms (such as those caused by autosomal recessive genes) to multifactorial inheritance, resulting from the variable interplay of many distinct genetic variants and environmental factors. © 2014 Bentham Science Publishers.

Romani M.,Neurogenetics Unit | Micalizzi A.,Neurogenetics Unit | Valente E.M.,Neurogenetics Unit | Valente E.M.,University of Salerno
The Lancet Neurology | Year: 2013

Joubert syndrome is a congenital cerebellar ataxia with autosomal recessive or X-linked inheritance, the diagnostic hallmark of which is a unique cerebellar and brainstem malformation recognisable on brain imaging-the so-called molar tooth sign. Neurological signs are present from the neonatal period and include hypotonia progressing to ataxia, global developmental delay, ocular motor apraxia, and breathing dysregulation. These signs are variably associated with multiorgan involvement, mainly of the retina, kidneys, skeleton, and liver. 21 causative genes have been identified so far, all of which encode for proteins of the primary cilium or its apparatus. The primary cilium is a subcellular organelle that has key roles in development and in many cellular functions, making Joubert syndrome part of the expanding family of ciliopathies. Notable clinical and genetic overlap exists between distinct ciliopathies, which can co-occur even within families. Such variability is probably explained by an oligogenic model of inheritance, in which the interplay of mutations, rare variants, and polymorphisms at distinct loci modulate the expressivity of the ciliary phenotype. © 2013 Elsevier Ltd.

Arena G.,Neurogenetics Unit | Arena G.,University of Rome La Sapienza | Gelmetti V.,Neurogenetics Unit | Torosantucci L.,Neurogenetics Unit | And 8 more authors.
Cell Death and Differentiation | Year: 2013

Mutations in the PINK1 gene are a frequent cause of autosomal recessive Parkinson's disease (PD). PINK1 encodes a mitochondrial kinase with neuroprotective activity, implicated in maintaining mitochondrial homeostasis and function. In concurrence with Parkin, PINK1 regulates mitochondrial trafficking and degradation of damaged mitochondria through mitophagy. Moreover, PINK1 can activate autophagy by interacting with the pro-autophagic protein Beclin-1. Here, we report that, upon mitochondrial depolarization, PINK1 interacts with and phosphorylates Bcl-xL, an anti-apoptotic protein also known to inhibit autophagy through its binding to Beclin-1. PINK1-Bcl-xL interaction does not interfere either with Beclin-1 release from Bcl-xL or the mitophagy pathway; rather it protects against cell death by hindering the pro-apoptotic cleavage of Bcl-xL. Our data provide a functional link between PINK1, Bcl-xL and apoptosis, suggesting a novel mechanism through which PINK1 regulates cell survival. This pathway could be relevant for the pathogenesis of PD as well as other diseases including cancer. © 2013 Macmillan Publishers Limited.

Petrucci S.,Neurogenetics Unit | Petrucci S.,University of Rome La Sapienza | Valente E.M.,Neurogenetics Unit | Valente E.M.,University of Salerno
Frontiers in Neurology | Year: 2013

Dystonias are heterogeneous hyperkinetic movement disorders characterized by involuntary muscle contractions which result in twisting and repetitive movements and abnormal postures. Several causative genes have been identified, but their genetic bases still remain elusive. Primary Torsion Dystonias (PTDs), in which dystonia is the only clinical sign, can be inherited in a monogenic fashion, and many genes and loci have been identified for autosomal dominant (DYT1/TOR1A; DYT6/THAP1; DYT4/TUBB4a; DYT7; DYT13; DYT21; DYT23/CIZ1; DYT24/ANO3; DYT25/GNAL) and recessive (DYT2; DYT17) forms. However most sporadic cases, especially those with late-onset, are likely multifactorial, with genetic and environmental factors interplaying to reach a threshold of disease. At present, genetic counseling of dystonia patients remains a difficult task. Recently non-motor clinical findings in dystonias, new highlights in the pathophysiology of the disease, and the availability of high-throughput genome-wide techniques are proving useful tools to better understand the complexity of PTD genetics. We briefly review the genetic basis of the most common forms of hereditary PTDs, and discuss relevant issues related to molecular diagnosis and genetic counseling. © 2013 Petrucci and Valente.

PubMed | Childrens Hospital at Westmead, Neurogenetics Unit, University of Rome La Sapienza, University of Salerno and 2 more.
Type: | Journal: Clinical genetics | Year: 2016

NDUFB11, a component of mitochondrial complex I, is a relatively small integral membrane protein, belonging to the supernumerary group of subunits, but proved to be absolutely essential for the assembly of an active complex I. Mutations in the X-linked nuclear-encoded NDUFB11 gene have recently been discovered in association with two distinct phenotypes, i.e. microphthalmia with linear skin defects and histiocytoid cardiomyopathy. We report on a male with complex I deficiency, caused by a de novo mutation in NDUFB11 and displaying early-onset sideroblastic anemia as the unique feature. This is the third report that describes a mutation in NDUFB11, but all are associated with a different phenotype. Our results further expand the molecular spectrum and associated clinical phenotype of NDUFB11 defects.

Melas P.A.,Neurogenetics Unit | Rogdaki M.,Neurogenetics Unit | Osby U.,Neurogenetics Unit | Osby U.,Tiohundra AB | And 3 more authors.
FASEB Journal | Year: 2012

Even though schizophrenia has a strong hereditary component, departures from simple genetic transmission are prominent. DNA methylation has emerged as an epigenetic explanatory candidate of schizophrenia's nonmendelian characteristics. To investigate this assumption, we examined genome-wide (global) and gene-specific DNA methylation levels, which are associated with genomic stability and gene expression activity, respectively. Analyses were conducted using DNA from leukocytes of patients with schizophrenia and controls. Global methylation results revealed a highly significant hypomethylation in patients with schizophrenia (P<2.0×10-6) and linear regression among patients generated a model in which antipsychotic treatment and disease onset explained 11% of the global methylation variance (adjusted R 2=0.11, ANOVA P<0.001). Specifically, haloperidol was associated with higher ("control-like") methylation (P=0.001), and early onset (a putative marker of schizophrenia severity) was associated with lower methylation (P=0.002). With regard to the gene-specific methylation analyses, and in accordance with the dopamine hypothesis of psychosis, we found that the analyzed region of S-COMT was hypermethylated in patients with schizophrenia (P=0.004). In summary, these data support the notion of a dysregulated epigenome in schizophrenia, which, at least globally, is more pronounced in early-onset patients and can be partly rescued by antipsychotic medication. In addition, blood DNA-methylation signatures show promise of serving as a schizophrenia biomarker in the future. © FASEB.

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