[Genetics in movement disorders--dystonia, tremor and chorea].
BACKGROUND
Several dystonias, Huntington's disease, essential tremor and various rare conditions are among the hereditary movement disorders, disorders with considerable genetic and clinical heterogeneity. It may be hoped that better understanding of the genetics and pathogenetic mechanisms involved will improve management.


METHODS
This review is based on personal experience and recent literature.


RESULTS
At least 13 types of dystonias are genetically defined. DYT 1 seems to be the most important, and is easily tested. The Huntington gene is readily available for symptomatic as well as presymptomatic testing. Presymptomatic testing gives rise to ethical concerns and require thorough genetic counselling. Also essential tremor seems to show an autosomal dominant inheritance, but the responsible gene(s) has not been identified.


CONCLUSIONS
As for other movement disorders, involvement of different genes may give similar phenotypes and defects in a single gene give rise to various different phenotypes.
Dietrichs
Espen
E
Nevrologisk avdeling, Rikshospitalet, 0027 Oslo. espen.dietrichs@klinmed.uio.no
Tallaksen
Chantal M E
CM
D020821:Dystonic Disorders / Q000175:diagnosis / Q000235:genetics* / Q000628:therapy; D020329:Essential Tremor / Q000175:diagnosis / Q000235:genetics* / Q000628:therapy; D005817:Genetic Counseling; D006801:Humans; D006816:Huntington Disease / Q000175:diagnosis / Q000188:drug therapy / Q000235:genetics*; D010641:Phenotype