Disease relevance of Myoclonus

• Progressive myoclonus epilepsy type 1 (EPM1, also known as Unverricht-Lundborg disease) is an autosomal recessive disorder characterized by progressively worsening myoclonic jerks, frequent generalized tonic-clonic seizures, and a slowly progressive decline in cognition [1].
• In seven patients the brain-stem infection produced transient myoclonus followed by the rapid onset of respiratory distress, cyanosis, poor peripheral perfusion, shock, coma, loss of the doll's eye reflex, and apnea (grade III disease); five of these patients died within 12 hours after admission [2].
• Mitochondrial encephalomyopathies are usually divided into three distinct clinical subgroups: (1) mitochondrial myopathy, encephalopathy, lactic acidosis and stroke-like episodes (MELAS); (2) myoclonus epilepsy associated with ragged-red fibres (MERRF); and (3) chronic progressive external ophthalmoplegia (CPEO) including Kearns-Sayre syndrome [3].
• Cranial diabetes insipidus occurred in 33 patients (73%) with sensorineural deafness (28, 62%) in the second decade; renal-tract abnormalities (26, 58%) presented in the third decade followed by neurological complications (cerebellar ataxia, myoclonus [28, 62%]) in the fourth decade [4].
• Progressive myoclonus epilepsies (PMEs) are a group of rare inherited disorders characterized by the association of epilepsy, myoclonus and progressive neurological deterioration [5].

Psychiatry related information on Myoclonus

• Clinical presentations and symptom frequencies are tabulated, and a multifactor analysis has been performed to obtain those combinations of symptoms and signs which occurred at least as often as the triad of dementia, myoclonus, and a positive electroencephalogram [6].
• Patients with Alzheimer's disease and a history of myoclonus had significantly lower choline acetyltransferase activity than did affected patients without myoclonus [7].
• Patients presented with progressive disorientation or agitation, sometimes associated with mild facial or limb myoclonus, that had begun 1 to 10 days (mean, 5 +/- 2 days) after starting cephalosporin treatment [8].
• Lithium-aggravated nocturnal myoclonus and restless legs syndrome [9].
• The first symptoms of Finnish vLINCL are concentration problems or motor clumsiness by 3 to 6 years of age, followed by mental retardation, visual failure, ataxia, myoclonus, and epilepsy [10].

High impact information on Myoclonus

• Myoclonus-dystonia syndrome (MDS; DYT11) is an autosomal dominant disorder characterized by bilateral, alcohol-sensitive myoclonic jerks involving mainly the arms and axial muscles [11].
• These results provide evidence that Glrb is necessary for postsynaptic expression of glycine receptor complexes, and suggest Glrb as a candidate gene for inherited myoclonus in other species [12].
• A scleroderma-like illness developed in a patient treated with L-5 hydroxytryptophan (L-5HTP) and carbidopa for intention myoclonus [13].
• Post-anoxic action myoclonus: improvement with valproic acid [14].
• Serotonin in essential myoclonus [15].

Chemical compound and disease context of Myoclonus

• Myoclonus in the young after 5-hydroxytryptophan [16].
• Spinal-fluid 5-hydroxyindoleacetic acid was 35% lower in patients with intention myoclonus than in controls (P less than 0.05) [17].
• Possible value of baclofen in myoclonus [18].
• A rare case of prednimustine-induced myoclonus [19].
• GABA receptor agonists in intention myoclonus [20].
• Medications known to occasionally trigger myoclonus (opioids, selective serotonin reuptake inhibitors, and a serotonin-norepinephrine reuptake inhibitor) were being taken by 7 patients [21].

Biological context of Myoclonus

• Furthermore, patients with Alzheimer disease who have extrapyramidal dysfunction or myoclonus are a distinct subgroup, with specific abnormalities of central monoamine markers of dopamine metabolism, serotonin metabolism, and the hydroxylation cofactor, biopterin [22].
• Cytoplasts from patients with myoclonus epilepsy with ragged-red fibers harboring a pathogenic point mutation at either nucleotide 8344 or 8356 in the human mitochondrial tRNA(Lys) gene were fused with human cells lacking endogenous mitochondrial DNA (mtDNA) [23].
• On the other hand, patients with the non-progressive myoclonus epilepsy phenotype showed smaller expansions (54-67 repeats) and a later age at onset (onset at or after age 21) [24].
• A novel Val154-->Ile mutation in the D2 dopamine receptor (DRD2) on chromosome 11q23 has recently been shown to be associated with myoclonus dystonia (M-D) in one large family [25].
• Electroencephalographic and cerebral evoked potential studies showed findings associated with myoclonus epilepsy [26].

Anatomical context of Myoclonus

• Deficit of spinal cord glycine/strychnine receptors in inherited myoclonus of Poll Hereford calves [27].
• We investigated the distribution and expression of mutant mtDNAs carrying the A-to-G mutation at position 8344 in the tRNA(Lys) gene in the skeletal muscle of four patients with myoclonus epilepsy and ragged-red fibers (MERRF) [28].
• Small Maf compound mutants display central nervous system neuronal degeneration, aberrant transcription, and Bach protein mislocalization coincident with myoclonus and abnormal startle response [29].
• Neuropsychiatric disorders, myoclonus, and dystonia in calcification of basal ganglia pathways [30].
• Ultrastructural study of hypertrophied inferior olives from three cases of palatal myoclonus revealed tha nerve cells not infrequently contained numerous round, homogeneously electron-dense granules (mean diameter, 360 nm) located within expanded cisternal profiles of rough endoplasmic reticulum (RER) [31].

Gene context of Myoclonus

• Myoclonic jerking and seizures were prominent in the PPT1 mice [32].
• Ectopic white matter neurons, a developmental abnormality that may be caused by the PSEN1 S169L mutation in a case of familial AD with myoclonus and seizures [33].
• The previously unrecognised association of myoclonus in two patients with LHON with the 11778/ND4 pathogenic mutation is described [34].
• Myoclonus and generalized digestive dysmotility in triple A syndrome with AAAS gene mutation [35].
• Seizures and myoclonus associated with antidepressant treatment: assessment of potential risk factors, including CYP2D6 and CYP2C19 polymorphisms, and treatment with CYP2D6 inhibitors [36].

Analytical, diagnostic and therapeutic context of Myoclonus

• Stimulus-induced myoclonus and burst suppression on EEG: effects of phenytoin toxicity [37].
• OBJECTIVE: To study specific serotonin (5-hydroxytryptamine [5-HT]) receptor subtype antagonists in an animal model of posthypoxic myoclonus [38].
• A single dose of p-chloroamphetamine, 10 mg per kilogram, produced postural abnormalities, tremor, myoclonus, and autonomic signs in rats 5 minutes after intraperitoneal injection [39].
• Outcome from coma after cardiopulmonary resuscitation: relation to seizures and myoclonus [40].
• For 3 to 8 h after the injection of DL-allylglycine at a subconvulsant dose (30 or 40 mg/kg, i.v.), the kindled cat showed a stable level of photosensitivity without any toxic effects and responded with various degrees of myoclonus or a generalized tonic-clonic convulsion when photic stimulation was repeated at hourly intervals [41].

References