Lafora Disease

A form of progressive myoclonic epilepsy

Diagnosis:

Clinical features plus EEG and pathology

Genetics:

EPM2A gene chr. 6q24, protein= laforin (a dual phosphatase),
EPM2B gene chr. 6q22.3 a.k.a. NHLRC1 gene, protein = malin (a E3 ubiquitin ligase)

Clinical features:

Age 10-18 y.o. epilepsy, segmental massive myoclonus, rapidly progressive mental deterioration (dementia), ataxia.

Findings on Investigations:

EEG:

  • Fast spike-wave and poly-spike-wave complexes, photosensitivity, multifocal abnormalities.
  • 50% have occipital spikes

Pathology:

Lafora bodies = intracellular periodic acid-Schiff-positive (PAS) inclusions (abnormal glucose polymer) in CNS (cortex & dentate nucleus), PNS, skin, liver or muscle.

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