Center for Human Genetics and Laboratory Diagnostics, Dr. Klein, Dr. Rost and Colleagues

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Dentatorubral-Pallidoluysian Atrophy (DRPLA) [G11.9]

OMIM number: 125370, 607462 (ATN1)

Dr. rer. biol. hum. Soheyla Chahrokh-Zadeh, Dr. med. Imma Rost

Scientific Background

DRPLA is an autosomal dominant neurodegenerative disease. Major signs and symptoms are progressive cerebellar ataxia as well as myoclonic epilepsy, choreoathetosis and dementia. The age of onset varies; usually the first signs and symptoms manifest at an early adult age. DRPLA occurs less frequently in Western countries than, for instance, in Japan.

The disease is caused by a CAG repeat expansion in the atrophin-1 gene ATN1. Just like other CAG triplet-repeat diseases, DRPLA is characterized by anticipation, i.e. an earlier onset in successive generations with increasing repeat length. The fact that the expansion of the repeat occurs especially in the case of inheritance from the father indicates instability especially in the male germ line. In predictive genetic testing, at-risk, asymptomatic individuals are tested, usually first-degree relatives of affected patients. According to the Genetic Diagnosis Act (GenDG) genetic counseling should be offered along with any genetic diagnostic procedure. In the case of predictive genetic testing, genetic counseling must be carried out prior to testing as well as after having received the result, unless there exists a written waiver of the at-risk person after having received written information on the content of the counseling. According to the recommendations of medical societies genetic testing should be accompanied by psychotherapeutic counseling prior to, during and after the genetic diagnostic procedure.