Progressive myoclonic epilepsies: definitive and still undetermined causes

Objective: To define the clinical spectrum and etiology of progressive myoclonic epilepsies (PMEs) in Italy using a database developed by the Genetics Commission of the Italian League against Epilepsy

Distribution of progressive myoclonus epilepsies in Italy; positively diagnosed and unclassified patients

Purpose: Progressive myoclonus epilepsies (PMEs) result from several genetic disorders. Few information are available about the prevalence of different PMEs. In spite of the progress in bio-molecular fields, the causative disorder remains undiagnosed in a significant fraction of the patients presenting with a PME phenotype. The aim of this study was collecting information about the frequency and geographical distribution of PMEs in Italy. Method: The Genetic Commission of the Italian League against epilepsy set up a data-base to include information dealing with PME patients referred by Italian Epilepsy Centres, including the following information: geographical origin of the parents, consanguinity, familiarity, age at the disease and myoclonus onset, general characteristics of the seizures and myoclonus and associated neurological defects, positive diagnosis, when reached. Negative results obtained in the different examinations performed during the diagnostic work-up had to be explicitly reported for the patients who didn't reach a positive diagnosis of the neurological disorder underlying the PME phenotype. Result: We collected 179 patients, including 74 with Unverricht-Lundborg disease, 33 with Lafora body disease, 25 with PME forms resulting from more rare genetic causes (neuronal ceroid-lipofuscinosis, action myoclonus renal syndrome, mitochondrial encephalopathies, other metametabolic disorders, celiac disease). Forty-seven patients were not classified, in spite of several investigations. We performed a tentative sub classification of these patients, based on details of phenotypic presentation (onset age, presence of relevant cognitive decline, seizure frequency and associated neurological signs). Conclusion: This study is expected to support further genetic studies suitable to detect new diseases giving rise to the PME phenotype

Observation of Gravitational Waves from the Coalescence of a 2.5−4.5 M⊙2.5-4.5~M_\odot Compact Object and a Neutron Star

International audienceWe report the observation of a coalescing compact binary with component masses $2.5-4.5~M_\odot$ and $1.2-2.0~M_\odot$ (all measurements quoted at the 90% credible level). The gravitational-wave signal GW230529_181500 was observed during the fourth observing run of the LIGO-Virgo-KAGRA detector network on 2023 May 29 by the LIGO Livingston Observatory. The primary component of the source has a mass less than $5~M_\odot$ at 99% credibility. We cannot definitively determine from gravitational-wave data alone whether either component of the source is a neutron star or a black hole. However, given existing estimates of the maximum neutron star mass, we find the most probable interpretation of the source to be the coalescence of a neutron star with a black hole that has a mass between the most massive neutron stars and the least massive black holes observed in the Galaxy. We estimate a merger rate density of $55^{+127}_{-47}~\text{Gpc}^{-3}\,\text{yr}^{-1}$ for compact binary coalescences with properties similar to the source of GW230529_181500; assuming that the source is a neutron star-black hole merger, GW230529_181500-like sources constitute about 60% of the total merger rate inferred for neutron star-black hole coalescences. The discovery of this system implies an increase in the expected rate of neutron star-black hole mergers with electromagnetic counterparts and provides further evidence for compact objects existing within the purported lower mass gap

Observation of Gravitational Waves from the Coalescence of a 2.5−4.5 M⊙2.5-4.5~M_\odot Compact Object and a Neutron Star

International audienceWe report the observation of a coalescing compact binary with component masses $2.5-4.5~M_\odot$ and $1.2-2.0~M_\odot$ (all measurements quoted at the 90% credible level). The gravitational-wave signal GW230529_181500 was observed during the fourth observing run of the LIGO-Virgo-KAGRA detector network on 2023 May 29 by the LIGO Livingston Observatory. The primary component of the source has a mass less than $5~M_\odot$ at 99% credibility. We cannot definitively determine from gravitational-wave data alone whether either component of the source is a neutron star or a black hole. However, given existing estimates of the maximum neutron star mass, we find the most probable interpretation of the source to be the coalescence of a neutron star with a black hole that has a mass between the most massive neutron stars and the least massive black holes observed in the Galaxy. We estimate a merger rate density of $55^{+127}_{-47}~\text{Gpc}^{-3}\,\text{yr}^{-1}$ for compact binary coalescences with properties similar to the source of GW230529_181500; assuming that the source is a neutron star-black hole merger, GW230529_181500-like sources constitute about 60% of the total merger rate inferred for neutron star-black hole coalescences. The discovery of this system implies an increase in the expected rate of neutron star-black hole mergers with electromagnetic counterparts and provides further evidence for compact objects existing within the purported lower mass gap