I was also diagnosed with ET a few years back, paid privately to see a neurologist as I thought it may have been the start of Parkinson’s, my mother was also diagnosed with ET and then Parkinson’s in her later life, it’s definitely a genetic condition.
The ET started in my left (fretting) hand, which is getting progressively worse, but it’s now also started in my right hand, my playing ability has been slightly affected and I definitely cannot play some stuff I played years ago.