However, clinical trials have developed certain compounds that could potentially change the future of Alzheimers disease treatments. Currently, diagnoses of Alzheimers is subpar, and better methods need to be utilized for various aspects of clinical diagnoses. Alzheimers has a 20% misdiagnosis rate.AD pathology is primarily characterized by the presence of amyloid plaques and neurofibrillary tangles. Plaques are made up of small peptides, typically 39–43 amino acids in length, called amyloid beta (also written as A-beta or Aβ). Amyloid beta is a fragment from a larger protein called amyloid precursor protein (APP), a transmembrane protein that penetrates through the neurons membrane. APP appears to play roles in normal neuron growth, survival and post-injury repair. APP is cleaved into smaller fragments by enzymes such as gamma secretase and beta secretase. One of these fragments gives rise to fibrils of amyloid beta which can self-assemble into the dense extracellular amyloid plaques. Parkinsons disease
Parkinsons disease (PD) is the second most common neurodegenerative disorder. It typically manifests as bradykinesia, rigidity, resting tremor and posture instability. The crude prevalence rate of PD has been reported to range from 15 per 100,000 to 12,500 per 100,000, and the incidence of PD from 15 per 100,000 to 328 per 100,000, with the disease being less common in Asian countries. PD is primarily characterized by death of dopaminergic neurons in the substantia nigra, a region of the midbrain. The cause of this selective cell death is unknown. Notably, alpha-synuclein-ubiquitin complexes and aggregates are observed to accumulate in Lewy bodies within affected neurons.
Diseases caused by the aggregation of proteins are known as proteopathies, and they are primarily caused by aggregates in the following structures:
cytosol, e.g. Parkinsons and Huntingtons
nucleus, e.g. Spinocerebellar ataxia type 1 (SCA1)
endoplasmic reticulum (ER), (as seen with neuroserpin mutations that cause familial encephalopathy with neuroserpin inclusion bodies)
extracellularly excreted proteins, amyloid-beta in Alzheimers diseaseThere are two main avenues eukaryotic cells use to remove troublesome proteins or organelles:

ubiquitin–proteasome: protein ubiquitin along with enzymes is key for the degradation of many proteins that cause proteopathies including polyQ expansions and alpha-synucleins. Research indicates proteasome enzymes may not be able to correctly cleave these irregular proteins, which could possibly result in a more toxic species. This is the primary route cells use to degrade proteins.Decreased proteasome activity is consistent with models in which intracellular protein aggregates form. It is still unknown whether or not these aggregates are a cause or a result of neurodegeneration. autophagy–lysosome pathways: a form of programmed cell death (PCD), this becomes the favorable route when a protein is aggregate-prone meaning it is a poor proteasome substrate. This can be split into two forms of autophagy: macroautophagy and chaperone-mediated autophagy (CMA).macroautophagy is involved with nutrient recycling of macromolecules under conditions of starvation, certain apoptotic pathways, and if absent, leads to the formation of ubiquinated inclusions. Experiments in mice with neuronally confined macroautophagy-gene knockouts develop intraneuronal aggregates leading to neurodegeneration. chaperone-mediated autophagy defects may also lead to neurodegeneration.