What gene testing should I request from my doctor when I finally get to see him?

I’m prepared to ask for DAT scan and I’d like to know which gene tests they can test for like Dimentia with Lewy Body (DLB) marker, Parkinsons marker, etcetra.

My symptoms for the last two years have been much in line with Parkinsons (one sided progressive stiffness/rigidity, dexterity worsening, gait issues, perceptual dizziness, extreme fatigue, joint pain in one hand).

I live in Japan and have to be very pointed in what I request because of the language barrier there is lots of miscommunication. So if possible I’d like to know which gene marker blood test I should ask for.

Thank you very much!

It would be good to know if you have the GBA mutation, because this might influence a decision on whether to have DBS -