Dentatorubropallidoluysian atrophy DRPLA

Diagnosis:

Genetics:

  • Autosomal dominant
  • DRPLA gene chr. 12. CAG repeat expansion (normal repeat number is 6-35). Protein= atrophin-1 protein.

Clinical features:

  • Chorea, ataxia, dementia, myoclonus

Pathology:

Gross: diffuse brain atrophy, worse in pons and cerebellum. Atrophy & discolouration of the globus pallidus, dentate nucleus, subthalamus & pontine tegmentum.
Microscopic: neuronal loss of dentate nucleus with grumose degeneration (eosinophilic granular material near the bodies of dentate neurons, it consists of preterminal axons). Neuronal loss & astrocytosis of external globus pallidus.
Neuronal loss also in: red nucleus, caudate, putamen, substantia nigra, subthalamus.
White matter degeneration of: cerebellar/olivary complex, superior cerebellar complex, posterior columns, spinocerebellar tracts.
Eosinophilic neuronal inclusions. Cytoplasmic inclusions in dentate nucleus neurons.
Immunohistochemistry: atrophin-1 positive intranuclear inclusions, ubiquitin positive intranuclear inclusions & cytoplasmic inclusions.

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