USMLE Step 1

-neurodegenerative disorder of the substantia nigra and locus ceruleus-depigmentation of substantia nigra pars compacta (loss of dopaminergic neurons)

TRAPTremor, Rigidity, Akinesia, Postural instability

Lewy bodies: eosinophilic cytoplasmic inclusions that consist of a dense core surrounded by a halo of 10 nm wide radiating fibrils
-These aggregates are the major feature of PD

Alpha-synuclein

Progressive muscle weakness and doesn't have any significant neuropathology

Dystrophin

Primarily the caudate nucleus

Trinucleotide repeat expansions inside the Huntingtin protein

1) most common cause of dementia in the elderly2) mutation in presenilin gene 3) Widespread cortical atrophy; neurofibrillary tangles (tau) and extracellular amyloid plaques

-frontotemporal dementia with parkinson linked to chr 17 (FTDP-17)-other neurodegen. disorders including AD, Pick's dz, progressive supranuclear palsy present w/ abnormal cytoplasmic accumulations of tau protein

Down syndrome patients

Early onset: APP (21), presenilin-1 (14), presenilin-2 (1)Late onset: ApoE4
10% have familial form

Dementia, aphasia, parkinsonian aspects; change in personality

1) Pick bodies (intracellular, aggregated tau protein)2) spares parietal lobe and posterior 2/3 of superior temporal gyrus

1) rapidly progressive (weeks to months)dementia with myoclonus 2) Spongiform cortex; prions (alpha helix to beta sheet)