Fig. 1. The similarities and differences in the main hallmarks of neurodegenerative diseases from the organ to molecular levels.

a AD is characterised by the inclusion of misfolded amyloid-β (Aβ) and neurofibrillary tangles in pyramidal neurons, primarily in the hippocampus and cortex regions of the brain. b PD is characterised by Lewy body aggregates composed of misfolded α-synuclein and degeneration of dopaminergic neurons in the substantia nigra region of the brain. c ALS is characterised by including mutant TAR DNA-binding protein 43 (TDP-43) and other proteins, degeneration of motor neurons in the motor cortex and spinal cord, and muscle atrophy with dysfunctional proteins. d HD is characterized by including mutant Huntingtin protein (mHTT) and degeneration of medium spiny neurons in the basal ganglia, and corpus striatum of the brain. AD Alzheimer’s disease, ALS amyotrophic lateral sclerosis, BDNF brain-derived neurotrophic factor, EAL endosomal-autophagic-lysosomal pathway, GABA gamma-aminobutyric acid, HD Huntington’s disease, PSEN presenilin 1, SNCA synuclein alpha.