title: Evaluation of the jitter phenomenon in myasthenic patients and their relatives.
abstract: Single fiber electromyography with jitter measurements and blocking evaluation was used for investigating 23 myasthenic patients, their 29 healthy relatives, coming from 10 families, and a control group of 10 subjects. Blocking was never seen in the healthy controls, and the jitter averaged some 30 microsec. Blocking was present in the myasthenic patients in 25.4% of the recorded potential pairs and there was a pathological jitter, which often extended over a few hundred microsec. The records of ten healthy relatives of patients were suggestive of slight but unquestionable abnormalities of neuromuscular transmission, viz. blocking and a jitter of over 60 microsec or more. The results demonstrate subclinical derangements of neuromuscular transmission in families of myasthenic patients, which points to a familial factor as involved in the pathomechanism of the disease.
mesh_terms: D000293:Adolescent; D000328:Adult; D004576:Electromyography; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009157:Myasthenia Gravis / Q000235:genetics / Q000503:physiopathology*; D009469:Neuromuscular Junction / Q000503:physiopathology; D009435:Synaptic Transmission