Mayo Clinic researchers have found Parkinson’s disease and Alzheimer’s disease patients more likely to be immediate blood relatives. Several intriguing leads prompted the researchers to hypothesize the connection of immediate family member’s susceptibility factors for Parkinson’s and Alzheimer’s disease.

What is particularly significant about this Mayo’s study is that previous studies done to assess the Parkinson’s and Alzheimer’s connection were done by asking just one family member to assess the other members of the family. In this current study each family member was independently assessed.

Cognitive impairment, or dementia, tends to occur in patients who have Parkinson’s disease. There is some suggestion it may be due to a shared susceptibility to genetic variations such as those in the apolipoprotein E gene. Another connection is that both diseases cause lesions on the brain. In Alzheimer’s disease, the lesions are called plaques and tangles. In Parkinson’s disease, the lesions are called Lewy bodies. Is is suspected that these brain  lesions may share common risk factors.

What the study was unable to establish was if the Parkinson’s and Alzheimer’s connection was genetic or non-genetic–such as a shared diet or perhaps something in the environment. What was determined is that the risk is particularly increased for relatives of patients who developed Parkinson’s disease before age 67. Further research is needed to determine susceptibility factors.