

It could be one of the leukodystrophies (not adrenal, only
boys get that).  Surely you've been to a university pediatric
neurology department.  If not that is the next step.  Biopsies
might help, especially if peripheral nerves are also affected.
There are so many of these diseases that would fit the symptoms
you gave that more can't be said at this time.

I agree with your surmise that it is an autosomal recessive.
If so, your normal children won't have to worry too much unless
they marry near relatives.  Most recessive genes are rare
except in inbred communities (e.g. Lithuanian Jews).
-- 
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Gordon Banks  N3JXP      | "Skepticism is the chastity of the intellect, and
geb@cadre.dsl.pitt.edu   |  it is shameful to surrender it too soon." 