Simona Petrucci

Diffusion-weighted magnetic resonance imaging in patients with partial status epilepticus

Purpose:u2002 Diffusion‐weighted magnetic resonance imaging (DWI) is used to detect changes in the distribution of water molecules in regions affected by various pathologies. Like other conditions, ictal epileptic activity, such as status epilepticus (SE), can cause regional vasogenic/cytotoxic edema that reflects hemodynamic and metabolic changes. This study describes the electroclinical and neuroimaging findings in 10 patients with partial SE whose DWI evaluation disclosed periictal changes related to sustained epileptic activity.

Phenotypic spectrum of alpha-synuclein mutations: New insights from patients and cellular models

The identification of the p.A53T mutation in the SNCA gene encoding alpha-synuclein (alpha-syn), as causative of autosomal dominant Parkinson disease (PD) represented a fundamental milestone, which paved the way to the extremely prolific field of PD genetics. Despite being the oldest player in this field and only a rare cause of inherited PD, research on alpha-syn has remained incredibly active over nearly twenty decades, leading to identify alpha-syn aggregation as a key mechanism in PD pathogenesis. The past two years have witnessed new exciting findings, with the discovery of at least three novel pathogenic mutations (p.H50Q, p.G51D and p.A53E) causative of complex parkinsonian phenotypes, and the identification of additional patients carrying old SNCA mutations (p.A53T, p.A30P, p.E46K and whole gene multiplications), which has allowed to further expand their phenotypic spectrum. This review aims at providing a clinical and functional update on the most recent findings in alpha-syn genetics, at the same time discussing novel avenues of SNCA research such as those on somatic mutations and epigenetic mechanisms.

Intravenous Levetiracetam as first-line treatment of status epilepticus in the elderly.

Fattouch J, Di Bonaventura C, Casciato S, Bonini F, Petrucci S, Lapenta L, Manfredi M, Prencipe M, Giallonardo AT. Intravenous Levtiracetam as first‐line treatment of status epilepticus in the elderly. Acta Neurol Scand: 2010: 121: 418–421.u2028© 2010 John Wiley & Sons A/S.

Global investigation and meta-analysis of the C9orf72 (G4C2)n repeat in Parkinson disease

Objectives: The objective of this study is to clarify the role of (G4C2)n expansions in the etiology of Parkinson disease (PD) in the worldwide multicenter Genetic Epidemiology of Parkinsons Disease (GEO-PD) cohort. Methods: C9orf72 (G4C2)n repeats were assessed in a GEO-PD cohort of 7,494 patients diagnosed with PD and 5,886 neurologically healthy control individuals ascertained in Europe, Asia, North America, and Australia. Results: A pathogenic (G4C2)n>60 expansion was detected in only 4 patients with PD (4/7,232; 0.055%), all with a positive family history of neurodegenerative dementia, amyotrophic lateral sclerosis, or atypical parkinsonism, while no carriers were detected with typical sporadic or familial PD. Meta-analysis revealed a small increase in risk of PD with an increasing number of (G4C2)n repeats; however, we could not detect a robust association between the C9orf72 (G4C2)n repeat and PD, and the population attributable risk was low. Conclusions: Together, these findings indicate that expansions in C9orf72 do not have a major role in the pathogenesis of PD. Testing for C9orf72 repeat expansions should only be considered in patients with PD who have overt symptoms of frontotemporal lobar degeneration/amyotrophic lateral sclerosis or apparent family history of neurodegenerative dementia or motor neuron disease.

Alpha-synuclein gene duplication: Marked intrafamilial variability in two novel pedigrees

Multiplications of the SNCA gene that encodes alpha‐synuclein are a rare cause of autosomal dominant Parkinsons disease (PD).

The protective effect of LRRK2 p.R1398H on risk of Parkinson’s disease is independent of MAPT and SNCA variants

The best validated susceptibility variants for Parkinsons disease are located in the α-synuclein (SNCA) and microtubule-associated protein tau (MAPT) genes. Recently, a protective p.N551K-R1398H-K1423K haplotype in the leucine-rich repeat kinase 2 (LRRK2) gene was identified, with p.R1398H appearing to be the most likely functional variant. To date, the consistency of the protective effect of LRRK2 p.R1398H across MAPT and SNCA variant genotypes has not been assessed. To address this, we examined 4 SNCA variants (rs181489, rs356219, rs11931074, and rs2583988), the MAPT H1-haplotype-defining variant rs1052553, and LRRK2 p.R1398H (rs7133914) in Caucasian (n = 10,322) and Asian (n = 2289) series. There was no evidence of an interaction of LRRK2 p.R1398H with MAPT or SNCA variants (all p ≥ 0.10); the protective effect of p.R1398H was observed at similar magnitude across MAPT and SNCA genotypes, and the risk effects of MAPT and SNCA variants were observed consistently for LRRK2 p.R1398H genotypes. Our results indicate that the association of LRRK2 p.R1398H with Parkinsons disease is independent of SNCA and MAPT variants, and vice versa, in Caucasian and Asian populations.

Phenotypic Variability of PINK1 Expression: 12 Years' Clinical Follow-up of Two Italian Families

Mutations in the PINK1 gene are the second most frequent cause of autosomal recessive early‐onset parkinsonism.

Genetic Issues in the Diagnosis of Dystonias

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.

Parkinson Disease Genetics: A "Continuum" From Mendelian to Multifactorial Inheritance.

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.

Cohort study of prevalence and phenomenology of tremor in dementia with Lewy bodies

To study prevalence, specific patterns and response to treatment of tremor in dementia with Lewy bodies (DLB), in comparison with other tremulous disorders prevalence, qualitative and quantitative features of tremor were studied in an incident cohort of 67 dopaminergic treatment naive DLB, 111 Parkinson’s Disease (PD) and 34 Essential Tremor (ET) patients. Tremulous DLB patients (tDLB) were compared with tremulous PD (tPD) and ET patients and followed for 2xa0years. Double blind placebo-controlled acute drug challenge with l-Dopa and alcohol was performed in all ET, 24 tDLB and 27 tPD. Effects of dopaminergic chronic treatment in all tDLB and tPD patients and primidone in 8 tDLB were also assessed. Tremor occurred in 44.76xa0% of DLB patients. The tDLB patients presented a complex pattern of mixed tremors, characterized by rest and postural/action tremor, including walking tremor and standing overflow in 50xa0% tDLB. Standing tremor with overflow was characteristic of tDLB (pxa0<xa00.001). Head tremor was more frequent in tDLB than tPD and ET (pxa0=xa00.001). The tDLB tremors were reduced by acute and chronic dopaminergic treatments (pxa0<xa00.01) but not by alcohol or primidone. Tremor occurs commonly in DLB patients with a complex mixed tremor pattern which shows a significant response to acute and chronic dopaminergic treatments. Recognizing that there is a clinical category of tremulous DLB may help the differential diagnosis of tremors.