Disease Information for Benign Familial Myoclonus

Clinical Manifestations
Signs & Symptoms
Involuntary Leg Movement Standing
Myoclonus/Myoclonic jerks on exam
Nocturnal Myoclonus
Clinical Presentation & Variations
Presents/Myoclonus Epilepsy Mental Decline <20
Disease Progression
Course/Benign course/disorder
Associated Diseases & Rule outs
Associated Disease & Complications
Benign Familial Myoclonus
Disease Mechanism & Classification
CLASS/Benign/Constitutional/essential disorder
CLASS/Pediatric disorders (ex)
CLASS/Neurologic (category)
PROCESS/Constitutional/essential disorder (ex)
PROCESS/Hereditofamilial (category)
PROCESS/Vegetative-Autonomic/Endocrine (category)
Benign Familial Myoclonus, Synonym/Benign essential myoclonia, Synonym/Essential Myoclonus Syndrome, Synonym/Essential Myoclonus-Dystonia variant, Synonym/Familial Essential Myoclonus, Synonym/Familial Myoclonus

Benign Familial Myoclonus is usually not progressive; variable presentation and severity worse with fatigue and anxiety; variable penetrance ; autosomal dominant;


Localization of a gene for benign adult familial myoclonic epilepsy to chromosome 8q23_3-q24_Benign adult familial myoclonic epilepsy is an autosomal dominant idiopathic epileptic syndrome characterized by adult-onset tremulous finger movement, myoclonus, epileptic seizures, and nonprogressive course; It was recently recognized in Japanese families; In this study, we report that the gene locus is assigned to the distal long arm of chromosome 8, by linkage analysis in a large Japanese kindred; epilepsy-related loci on chromosome 8q have been recognized-one on chromosome 8q13-21 (familial febrile convulsion) and two others on chromosome 8q24 (KCNQ3 and childhood absence epilepsy)-the locus assigned here is distinct from these three epilepsy-related loci; This study establishes the presence of a new epilepsy-related locus on 8q23_3-q24_11

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A case of familial myoclonus showing extremely benign clinical course][Article in Japanese] Nagayama S, Kishikawa H, Yukitake M, Matsui M, Kuroda Y.

We report a patient with familial myoclonus showing an extremely benign clinical course;The patient was a 70-year-old woman, who first noticed shaking of hands at age of 25;The symptom did not worsen for more than 40 years;She visited our hospital at the age of 70 because of disturbance in chores because of worsening of her hand shaking in the past one year; A family history showed that 4 members had similar symptoms and that the two were afflicted with fits of loss of consciousness; On neurologic examination, rhythmic myoclonic jerks were noted in all the extremities, more in the upper limbs, both at rest and during action;Tandem gait was mildly disturbed;


External Links Related to Benign Familial Myoclonus
PubMed (National Library of Medicine)
NGC (National Guideline Clearinghouse)
Medscape (eMedicine)
Harrison's Online (accessmedicine)
NEJM (The New England Journal of Medicine)