Amyotrophic lateral sclerosis: electrophoretic study of amorphous material of skin

We studied skin from patients with amyotrophic lateral sclerosis (ALS) and controls by electron microscopy, and analyzed it by sodium dodecyl sulfate-poly-acrylamide gel electrophoresis (SDS-PAGE) and two-dimensional gel electrophoresis. On electron microscopy, the most conspicuous finding in ALS was a markedly increased amount of amorphous material in the ground substance, which became more marked in proportion to the duration of ALS. SDS-PAGE analysis showed that in ALS patients the staining intensity of a low-molecular weight band (approx. 12.5 kDa, band "g") became more marked with the duration of ALS. Two-dimensional gel electrophoresis revealed that band "g" consisted of a single component with a basic isoelectric point. It is thought that the substance corresponding to band "g" is a major constituent of the amorphous material.