Debbie - I went to Johns Hopkins in Dec of 2021, the neuro doc said that in many cases like mine, idiopathic, the "belief" and...only a belief...by various docs is that it is caused by a genetic issue. I've had blood work done for CMT, tests at Mayo, MRI of brain, etc. There is a reason for my PN and tests can show what nerves are impacted but the why is the mystery. So, how many of us have PN possibly caused by a genetic issue? When we can't get a proven answer to resolve our curiosity, the genetic starts to make some sense.