What's the connection between Parkinson's Disease and Alzheimer's Disease?

Parkinson’s disease is characterized by accumulations of the protein alpha-synuclein and the development of Lewy Bodies. The areas that these Lewy Bodies are found vary from person to person with Parkinson’s Disease. Parkinson’s disease normally does not develop in younger people, and is most common in people over the age of 50. Diagnosis of Parkinson’s is mainly based upon symptoms exhibited by the patient, but rely also on various types of imaging of the brain. In late stages of Parkinson’s Disease, sometimes Alzheimer’s disease is developed. So what is the connection between Parkinson’s disease and Alzheimer’s disease? Does Parkinson’s disease lead to Alzheimer’s Disease? Well, Alzheimer’s disease is also characterized by the accumulation of a protein, however it is a different protein called Tau Protein. This accumulated tau proteins lead to neurofibrillary tangles in the brain which cause the development of Alzheimer’s Disease. Is the only connection between the two diseases the accumulation of a protein in the brain? More research needs to be done on this matter. Parkinson’s disease does not have a known cause. If the direct cause of Parkinson’s disease becomes known, the connection between Alzheimer’s disease and Parkinson’s disease will be one step closer to being determined.