Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0027066 (myoclonus)
 4,275 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Severe myoclonic epilepsy in infants (SME) is one of the most malignant epileptic syndromes recognized in the latest classification of epileptic syndromes. The clinical details and electroencephalographic (EEG) characteristics have been elucidated by Dravet et al. The diagnosis of SME depends largely on the combination of clinical and EEG manifestations at different ages, of which the presence of myoclonic seizures appears to be the most important. However, because of the inclusion of different types of myoclonic attack and the lack of strict criteria for diagnosing SME, there has been some confusion as to whether patients without myoclonic seizures or myoclonus should be classified as SME, despite other identical clinical symptoms (SME borderlands (SMEB) group). Among the various clinical manifestations characterizing SME, special attention has been paid to seizures easily precipitated by fever and hot baths in Japan. We have demonstrated that the onset of myoclonic attack in these patients is very sensitive to the elevation of body temperature itself rather than its etiology. Using simultaneous EEG and rectal temperature monitoring during hot water immersion, we showed that epileptic discharges increased in frequency, and eventually developed into seizures at temperatures over 38 degrees C. We believe that the unique fever sensitivity observed in SME is similar to, but more intense than that of febrile convulsions. We have also identified a group of cases who have had innumerous myoclonic and atypical absence seizures daily which were sensitive to the constant bright light illumination. In these cases, spike discharges increased or decreased depending on the intensity of constant light illumination. Although these cases form the most resistant SME group, they lost the constant light sensitivity with increasing age, leaving only relatively common types of fever-sensitive grand mal seizures (FSGM) at the age of around 5 years. In the long run, only convulsive seizures continue, while myoclonic or absence seizures and photosensitivity disappear with advancing age, thus it is conceivable that SMEB constitutes a basic epileptic condition underlying SME. There is a clinical continuum that extends from the mildest end of SMEB to the severest end of SME with constant light sensitivity, with intermediates of frequent or infrequent myoclonic and absence seizures in-between. This spectrum concept appropriately explains the clinical variabilities between SME and SMEB during early childhood.
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PMID:Severe myoclonic epilepsy in infants--a review based on the Tokyo Women's Medical University series of 84 cases. 1170 Dec 88

Two inbred strains of the Mongolian gerbil with different phenotypes in seizure behaviour and coat color were newly established. LSAG/Nu has low seizure susceptibility and albino phenotypes, whereas SPBG/Nu has seizure-prone and black coat color phenotypes. LSAG was compared with SPBG as to seizure incidence and grade. Mean ages at seizure onset of LSAG and SPBG were 6 and 3 months, respectively. Seizure incidences in over 9 months old LSAG and SPBG gerbils were 37.3% (66/177) and 95.2% (118/124), respectively. LSAG has a significantly lower incidence (p < 0.001) and grade (p < 0.001) of seizures than SPBG. Only a few seizing LSAG gerbils exhibited myoclonus to tonic-clonic seizure progression. These results suggest that LSAG has some mechanisms which delay the onset of seizures and prevent them from becoming serious. Both strains of gerbils can be expected to be useful animal models for the study of human idiopathic generalized epilepsy.
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PMID:Newly established low seizure susceptible and seizure-prone inbred strains of Mongolian gerbil. 1280 93

A young Chinese male was admitted for a generalised tonic-clonic seizure preceded by a week-long history of fever. Subsequently, he developed continuous myoclonic jerks in all four limbs, with clear left sided predominance, and no accompanying clouding of consciousness. Contrast MRI of the brain demonstrated a venous angioma in the right cingulate gyrus. Over the next few days, the clinical picture evolved, with focal motor status involving primarily the left lower limb and the abdomen. These movements resolved with anticonvulsant therapy. This case illustrates generalised myoclonus arising from a focal brain abnormality. The epileptiform aetiology became obvious only after evolution into the typical features of a focal motor seizure and supportive neuroimaging. This demonstrates the protean manifestations of epileptic seizures which have been ascribed to the cingulate gyrus. The lack of clear declarative clinical and EEG features highlights the melding of the fields of epileptology and movement disorders.
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PMID:Generalised myoclonus evolving into epilepsia partialis continua due to a cingulate gyrus lesion: case report and review of the literature. 1546 5

Recent identifications of genes responsible for epilepsies are now contributing to diagnosis and treatment. Mutations of voltage-gated sodium channel genes SCN1A and SCN2A have been reported in epilepsies with a variety of phenotypes including generalized epilepsy with febrile seizures plus (GEFS +), severe myoclonic epilepsy in infancy (SMEI), intractable childhood epilepsy with generalized tonic-clonic seizures (ICEGTC), and benign familial neonatal-infantile seizures (BFNIS). We also identified a sporadic nonsense mutation of SCN2A in a patient with intractable epilepsy with severe mental decline. Lafora's disease (LD) is a fatal autosomal recessive epilepsy characterized by stimuli sensitive myoclonus, grand mal seizures, and progressive intellectual and neurological deterioration. The EPM2A gene has been reported to be responsible for LD. We found multiple disease mutations of EPM2A in LD patients, and also identified a subclass of LD who shows an early onset cognitive defect and correlated with EPM2A exon 1 mutations. We reported that the laforin protein encoded by the EPM2A gene has a dual-specificity phosphatase activity, associates with polyribosome, and interacts with the HIRIP5 protein with NifU-like domain. We recently generated and reported the EPM2A KO mice those develop neurodegeneration and other features similar to those of LD patients.
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PMID:[Molecular genetics of epilepsy]. 1565 14

This chapter assesses probable epileptic syndromes within the idiopathic generalized epilepsies (IGE) that have not yet been recognized by the International League Against Epilepsy (ILAE). Jeavons syndrome, a purely reflex IGE that predominantly manifests with eyelid myoclonia and electroencephalogram (EEG) abnormalities on eye closure, is the most distinct and undisputed of the syndromes. Another is autosomal-dominant cortical tremor, myoclonus, and epilepsy, a purely monogenic disorder that has been documented in numerous reports, mainly from Japan and Italy. Perioral myclonia with absences is certainly a seizure type that may constitute an IGE syndrome when it is associated with a number of other clinical and EEG manifestations. Similarly, many patients suffer for years from phantom absences, a type of mild absence, before a first generalized tonic-clonic seizure that usually occurs in adulthood. Both perioral myoclonia with absences and phantom absences are clinically significant because they are probably lifelong and are associated with a very high incidence (around 50%) of absence status epilepticus that may escape diagnosis and appropriate treatment. The position of early childhood IGE, which manifests mainly with typical absence seizures that are distinctly different from childhood absence epilepsy and other recognized IGE syndromes, is less clear. The prevalence of these syndromes is significant. Their identification allows better clinical management and is important for genetic research and counselling. In addition, their recognition permits application of exclusion criteria for a more purified definition and a better understanding of the true boundaries of the other IGE syndromes already accepted by the ILAE.
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PMID:Syndromes of idiopathic generalized epilepsies not recognized by the International League Against Epilepsy. 1630 76

A hyperosmolar ionic contrast medium, ioxithalamate (Telebrix), was inadvertently injected intrathecally to a dog during myelography. The resultant severe adverse effects were myoclonus, uncontrollable seizures, and hyperthermia. These symptoms have been described by some authors as "ascending tonic-clonic seizure syndrome". The dog completely recovered within 24 h. The literature on 47 humans receiving intrathecal ionic contrast medium after 1966, one dog and one horse was reviewed, including the drugs involved, the circumstances of their use, and the symptoms, treatment and outcome of patients who received the drugs intrathecally. Recommendations to prevent such a misuse are given. The present report and review are a reminder that ionic contrast media are absolutely contraindicated for myelography. Only nonionic contrast media can be used intrathecally. All of the hyperosmolar contrast media are ionic and therefore contraindicated for myelography.
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PMID:Inadvertent intrathecal administration of ionic contrast medium to a dog. 1789 73

The clinical and EEG data of a 49-year-old man with myoclonic and generalized tonic-clonic seizures resulting from early childhood encephalitis are described. He experienced no tonic-clonic seizure for 10 years before brief exposure first to 60 mg/day duloxetine and then to 20mg/day paroxetine for depressive symptoms. These drugs were separately prescribed at a 9-month interval, and after beginning each drug, the patient experienced tonic-clonic seizures of worsening intensity and myoclonus of increasing frequency. Clinical features correlated with subcontinuous, generalized spike-wave discharges on the EEG. Discontinuation of antidepressant treatment resulted in rapid disappearance of clinical and electrophysiological manifestations of myoclonic status. We suggest care must be taken when using serotonin-noradrenaline reuptake inhibitors (SNRIs) or selective serotonin reuptake inhibitors (SSRIs), as these drugs pose the risk of complications in the specific population of people with myoclonic seizures.
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PMID:Antidepressant-associated myoclonic status in a patient with symptomatic generalized epilepsy: does risk occur with therapeutic doses? 1943 83

In this study, the authors characterized the clinical and EEG features of adult patients with Down syndrome who were referred, for more than a 10-year period, to the Epilepsy Clinic in the Cork University Hospital. A retrospective audit of the charts of 28 patients with Down syndrome who had an EEG performed in the Cork University Hospital between January 1, 2000, and September 30, 2009, including clinical follow-up, was carried out. Demographics, age at first seizure, seizure types, EEG findings, antiepileptic drugs, psychoactive medications, and seizure control were documented. Seizures most commonly began in the fourth decade of life. Generalized tonic-clonic seizures were the most common type of seizures (15 patients, 54%), followed by complex partial seizures (5 patients, 18%) and generalized myoclonus (4 patients, 15%). A number of patients had more than one type of seizure. Diffuse background slowing was the dominant EEG abnormality seen in 17 patients (60%). Epileptiform activity was present in 5 patients (18%): 2 had focal epileptiform discharges in the frontal regions, 1 in the central region, 1 in the central posterior region bilaterally, and 1 in the temporal regions. The six patients who had poor seizure control were those who had seizure onset from the fourth decade onward and clinically had complex partial seizures in combination with either generalized tonic-clonic or generalized myoclonus; four of them had epileptiform activity on EEG, with two having focal frontal epileptiform discharges: one in the central posterior areas bilaterally and one in the temporal regions. Five of the 28 patients had a normal EEG and 3 of these had a seizure disorder. There was no correlation found between use of psychoactive drugs and increased frequency/poor seizure control in patients in our study. This study documents the variability of clinical and electrophysiologic features in a well-characterized cohort of patients with Down syndrome with adult-onset epilepsy.
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PMID:Clinical and EEG features of seizures in adults with down syndrome. 2194 60

Juvenile myoclonic epilepsy (JME) is a widely recognized presumed genetic, electroclinical idiopathic generalized epilepsy syndrome. The prevalence of JME in large cohorts has been estimated to be 5% to 10% of all epilepsies and around 18% of idiopathic generalized epilepsies but may be lower in some settings. There is a marked female predominance. However, some of the basic epidemiology of JME is not well known, possibly because the syndrome is not sharply defined. A questionnaire study about the diagnostic criteria for JME suggests that diagnosis of JME can be made with the history of myoclonus plus a single generalized tonic-clonic seizure plus generalized fast spike-waves or polyspike-waves on the EEG. However, until these diagnostic criteria are fully accepted, the detailed epidemiology of JME will remain imprecise.
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PMID:Epidemiology of juvenile myoclonic epilepsy. 2375 73

A 41-year-old man, during a neurological consultation, reported "chin twitching" over a period of a week, which was diagnosed as intermittent perioral myoclonia. With only one tonic-clonic seizure seven years before, he had mentioned several episodes of chin twitching over the years. In the clinic, there were intermittent chin movements without apparent confusion, as he was able to provide a complete history and was fully oriented with intact memory. His video-EEG showed paroxysms of polyspike and slow-wave activity, with the longest burst-free interval being 20 seconds. Discharges were maximal over the fronto-central regions, correlating with the chin myoclonus. He was able to tap his hand continuously, and remained alert. The case represents an atypical presentation of idiopathic generalised epilepsy without manifestation of absence or limb myoclonus. Although juvenile myoclonic epilepsy and other idiopathic epilepsies are rarely associated with perioral myoclonia, this sign was the principal clinical feature for this patient. Oral treatment with levetiracetam resolved his seizures.
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PMID:Generalised electrographic seizures presenting as perioral myoclonia. 2456 49


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