Table 1.

Pathological characteristics, genetic factors and clinical symptoms of Alzheimer’s disease (AD), Parkinson’s disease (PD), Huntington’s disease (HD), and amyotrophic lateral sclerosis (ALS) [1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25,26,27,28,29,30].

Diseases	Characteristics	Genetics factors	Symptoms	Actual treatments
AD	Senile plaques from extracellular amyloid-Aβ accumulation, Intracellular neurofibrillary tangles, Tau protein aggregation, Irreversible neuronal loss, Brain atrophy	Inherited form (70% of patients): mutations of APP, PSEN1 or PSEN2. Sporadic form (30%): presence of ApoE4 allele in the ApoE gene	Progressive memory loss, Decision judgement loss, Autonomy loss	Anticholinergics (tacrine, rivastigmine, galantamine and donepezil), Memantine, Antipsychotics, NSAIDs
PD	α-Synucleinopathy, Presence of Lewy bodies, Degeneration of dopaminergic neurons in the substance nigra of the brain, Dopamine deficiency	Gene mutations: α-synuclein SNCA, Parkin PRKN, PARK7, PINK1, LRRK2, GBA, DJ-1, VPS35, EIF4G1, DNAJC13 and CHCHD2	Hypokinesia, Bradykinesia, Rigidity, Postural instability, Neuropsychiatric disturbances	Levodopa, Dopamine agonists, MAO-B inhibitors, COMT inhibitors, Anticholinergics
HD	Accumulation of mutant Huntingtin protein in the brain	Expansion of CAG trinucleotide in Huntingtin gene (HTT)	Chorea, Cognitive and neuropsychiatric disorders	Tetrabenazine, Neuroleptics, Antipsychotics
ALS	Progressive degeneration of motor neurons	Sporadic form: 90% of patients Inherited form: 10% Mutations of SOD1, TARDBP, FUS, UBQLN2, OPTN, and C9ORF72 genes	Spasms, Muscle atrophy, Squelettal muscle paralysis, Cognitive or behavioral dysfunction	Riluzole