The distinction is something I don't understand either. I have the same issue with our state insurance fund for the "uninsurable". There is a 24-month wait before I am eligible for Medicare. Because my SSDI benefit is above the income limit I'm not eligible for Medicaid. But, if I had diabetic neuropathy, I would have one of the 50 disorders that qualifies as uninsurable, and would therefore be eligible for that insurance fund.

It makes absolutely no sense to draw any distinction between diabetic neuropathy and peripheral. But since there is a distinction, it would seem that a person with diabetic neuropathy in theory has more control over their neuropathy than a person with PN of unknown origin. At least a diabetic knows the underlying cause and can treat that. But, a person with PN of unknown cause can only treat the symptoms, which in my mind would make them more in need of assistance.

My 2 cents: You have gone this far. Appeal the appeal. You have nothing to loose. Good luck to you and Alan.