This has always been quite concerning to me as I've had a worsening essential tremor that was slight in my early twenties but is quite observable now that I'm in my thirties. The confounding effect that really hurts me here is that my father has had a benign essential tremor for his whole life - so there's a constant see-saw internally and with medical practitioners about whether my tremor is something to be concerned about or not.
I suspect that my mom developing a tremor is what turned her DRD, which was in retrospect similar to what myself and my grandma have, into Parkinson's. As far as I can tell, for my family anyway, developing the a tremor will rapidly deplete what little Dopamine we can produce and lead to normal'ish looking Parkinson's.
The genetic defects associated with this are I believe a spectrum though, and we happen to be close to one side of it. If you have any symptoms related to DRD, I would see a movement disorder specialist and ask for a trial of carbo/levo. It'll be immediately obvious if it helps, and if you don't have any problems with Dopamine production it won't do anything (except for some mild side effects).
