Ed,
Genetic neuropathy is in the minority of causes as there are over 200 known causes for neuropathy. Most of us fall into the overall general terms of :
toxic- anything from alcohol to penicilin shots or flu shots, exposure to chemical from the workplace to the garden, and everything you can think of in between
compression- pinched discs to botched surgery that the surgeon won't admit to
environmental- something causes an allergy or some sort of reaction that acts as a trigger
inherited- the biggest group is middle European klineage and descendants, but is not exclusive there
and a few other miscellaneous things.
'Glenntaj', here- has a lot of info on all of the causes

The main thing is to identify the triggers that cause the severity or onset of symptoms, identify the types of symptoms, and try to find a med or supplement, or something that helps alleviate symptoms & pain. since there is no cure, yet- searching for the cause can be an expensive road that could lead to a dead end, or at least a stop sign that says "Road under construction you can go no farther."
Be content to treat symptoms and not fret about whether your children will get it. Worry about yourself and get your head under control regarding acceptance and experience of treatment as to how to live as normal a life, with PN. If you had diabetes, you'd live with it -and the treatment necessary to live normally. You won't necessarily know why you got the diabetes, but you have it.
This is no different.