Clinical Reference · Movement Disorders

DRPLA

Dentatorubral-pallidoluysian atrophy — one CAG repeat, many syndromes
Illustration of a patient with chorea and myoclonus
Chorea + myoclonus
AD polyglutamine (CAG)
GeneATN1 (atrophin-1) · 12p
MutationCAG repeat (polyglutamine)
strong anticipation (worse paternally)
InheritanceAutosomal dominant
OnsetBimodal — juvenile vs adult
A family with progressively earlier, worse ataxia, chorea, myoclonic epilepsy and dementia across generations.
Key clinical features
  • Progressive cerebellar ataxia
  • Chorea & dystonia
  • Myoclonus + seizures/epilepsy
  • Dementia & psychiatric change
  • Juvenile form = progressive myoclonic epilepsy
  • Adult form = ataxia–chorea–dementia
◆ Signature clue

Worsening, earlier-onset ataxia + chorea + myoclonic epilepsy + dementia across generations (anticipation) → DRPLA — especially in Japanese ancestry. The African-American kindred variant = Haw River syndrome.

Diagnosis
CAG-repeat testing of ATN1. MRI: cerebellar + brainstem atrophy, white-matter changes.
Management
Symptomatic — antiepileptics for myoclonus/seizures (avoid agents that worsen myoclonus); PT, psychiatric care. No disease-modifying therapy.
Board pearlA single polyglutamine CAG disorder whose whole phenotype shifts with age of onset — juvenile looks like myoclonic epilepsy, adult like Huntington-plus-ataxia.
Sources: Neuro.Wiki › Movement Disorders / DRPLA. Educational reference — not a substitute for clinical judgment. Neuro.Wiki