Progressive myoclonus epilepsy: extraneuronal brown pigment deposition and system neurodegeneration in the brains of <scp>J</scp>apanese patients with novel <scp><i>SCARB2</i></scp> mutations

The frameshift mutation detected in the patient with late-onset disease is a hitherto undescribed, unique type of SCARB2 gene mutation. The present two patients are the first reported to have clearly demonstrated both extraneuronal brown pigment deposition and system neurodegeneration as neuropathological features of PME with SCARB2 mutations.