Researchers have found that it's possible for a skin test to determine Parkinson's and Alzheimer's diseases by detecting elevated levels of protein characteristic to the two.

In a study to be presented at the 67th annual meeting of the American Academy of Neurology in April, researchers hypothesized that because skin is essentially the same as tissues in the brain, originating from the same source during fetal development, testing it might yield the same types of proteins found in the brains of those with Parkinson's and Alzheimer's diseases.

"Until now, pathological confirmation was not possible without a brain biopsy, so these diseases often go unrecognized until after the disease has progressed," explained Ildefonso Rodriguez-Leyva, M.D. from the University of San Luis Potosi and one of the authors for the study, adding the new test allows for the identification of potential biomarkers that will help in spotting and diagnosing the diseases early.

To test their hypothesis, researchers took skin samples from 16 people with Parkinson's disease, 20 with Alzheimer's and 17 people with other forms of dementia as well as skin biopsies from 12 healthy individuals. All subjects were from the same age group. The researchers tested the skin samples for abnormal proteins and found that those with Parkinson's and Alzheimer's have seven times more tau protein than the group with healthy individuals. At the same time, the group with Parkinson's had eight times more alpha-synuclein protein compared to the control group.

Rodriguez-Leyva and colleagues believe more research is required to confirm the results of their study but their findings have opened up the opportunity for skin biopsies to be used to learn more about Parkinson's, Alzheimer's and dementia, in general. Skin samples being more readily available than brain tissues will also facilitate research because more material will be available.

Alzheimer's disease is the sixth leading cause of death in Americans. About 5.4 million individuals in the United States are currently living with the disease, while one million are affected by Parkinson's disease. Every year, new cases of Parkinson's disease reportedly number at least 60,000.

In Alzheimer's disease, progressive loss of brain cells leads to a decline in mental ability and memory problems. In Parkinson's, loss is focused on nerve cells, leading to slow movement, stiff muscles and tremors.