Connective Tissue Disorders Vasculitides generally produce a mononeuropathy characterized by infarction of fasciculi within nerves. Diagnosis is made by demonstrating porphobilinogen in the urine. Fabry's disease is X-linked, presenting in males, and is due to ceramide Trihexosidase deficiency. Curiously sensory action potentials are retained in spite of painful paresthesias. Refsum's disease, accompanied by hypertrophic neuropathy, ataxia, deafness atypical retinitis pigmentosa, ichthyosis results from a failure to break down phytanic acid.
Treatment consists of elimination of leafy vegetables and animal fats from the diet.
Dejerine-Sottas recessive disorder produces severe neuropathy. Dominantly inherited hypertrophic peroneal muscular atrophy can produce very mild to moderate deficit. The pure motor neuropathy with normal conduction velocity is recessive in inheritance and felt by many to be a type of spinal muscular atrophy. There is also a sensorimotor neuropathy with normal conduction velocities and moderate involvement. This is of dominant inheritance.