Jager, thank you for your reply, The Dr. has not given me and cause for my SFN, My daughter is 53 years old. Genetics can and do play a roll in developing the disorder but is only about 5 % to blame, for the most part SFN is still a mystery. There is so much more to learn about this disease. While research is ongoing, for those of us who have it, the results can't come soon enough. I was borderline diabetic for years(5) with an A1C never over 6, I took Metformin for about 5 years till my A1C came back under 6 and I was having episodes of hypoglycemia so the Dr took me off the med all together and I've been fine, so I have to question diabetes as the sole cause of Lg Fiber Neuropathy.. When I ask what the cause was, I was told it could be this or that , in other words they don;t know what caused it. As for environmental risk factors, the only one I would know of is that I smoke and so does my daughter which doesn't help I am sure, but is not the cause.. All my lab work comes back fine as does my daughters. Guess we will just have to wait and see. thanks again for your reply, God Bless, Jeanie