Many researchers believe that, except in very special cases, a family history of PD does not mean an exclusively genetic cause. It may mean a genetic propensity, but even so
environment is believed to play an important role in the development of the disease. Members of a family may be exposed to the same environmental factors and PD may exist within a family without any genetic component. I was recently speaking with a genetics researcher about the impact of genes on PD expression and his comment was that he didn’t know how much genes and environment were respectively responsible for the development of PD, but he knew it took both.
There is a family history of Parkinson’s disease in five to ten percent of patients. This is often (but not always) due to a shared genetic propensity, but it is important to know that inheriting a propensity for Parkinson’s disease does not mean inheriting the disease. There are several things that a person with this genetic propensity can do to protect the brain, and you might want to talk to a neurologist about this. One uncontroversial thing you can do is get lots of strenuous physical exercise. A daily rigorous cardiovascular routine has been shown to be neuroprotective. Also, blueberries (and some other fruit) are good for brain health.