Table 1.

Neurodegenerative disorders and US FDA-approved drugs

Disorder	Affected neurons	Age of onset	Sporadic or genetic	Familial disease genes	Drug	Mechanism of action or target	Date of US FDA approval	Effect
AD	Cortical and hippocampal neurons	>65	95% sporadic, 5% familial	APP PSEN1 PSEN2	Memantine (Namenda) Donepezil (Aricept), Galantamine (Razadyne), Rivastigmine (Exelon).	Blocks NMDA receptors, reduces excitotoxicity Acetylcholinesterase inhibitors. Increase concentration of Ach in the brain	2003 1996 2001 2000	Mild improvement in cognitive measures Mild improvement in cognitive measures
PD	Dopaminergic neurons in substantia nigra pars compacta	>65	95% sporadic, 5% familial	Synuclein LRRK2 Parkin PINK1 DJ-1	L-Dopa (Levodopa)	Increases amount of dopamine in substantia nigra neurons	1970	Symptomatic benefit
ALS	Motor neurons	40–60	95% sporadic, 5% familial	SOD1	Riluzole (Rilutek)	Antiglutamate (activator of glutamate uptake, inhibitor of NMDAR and Na+ channels)	1995	Extends survival by several months
HD	Striatal medium spiny neurons	40–50	100% familial	Huntingtin	Tetrabenazine (Xenazine)	Antidopamine (VMAT2 inhibitor, reduces amount of released dopamine)	2008	Reduction in chorea
SCAs	Various brain regions involved in motor control	40–50	100% familial	Ataxins	N/A	N/A	N/A	N/A