Abnormal protein and lipid compositions of the cerebral myelin of a patient with maple syrup urine disease.

Biochemical analyses were performed on the myelin isolated from the brain tissue of a patient with maple syrup urine disease. He was mostly treated by dietary management from day 8 after his birth until he died at 4 years and 5 months of age. It was found that the myelin contained major proteolipid-protein and high molecular weight protein and a very minor basic protein. The lipid composition of the myelin showed a marked decrease in phosphatidylethanolamine, but there was no remarkable reduction of cerebroside and sulfatide as well as other phospholipids in the myelin. Although the ganglioside composition of the myelin indicated that GM1 was a major ganglioside just like in the normal myelin, the myelin had an abnormal composition of an higher proportion of GD3 and a lower proportion of GM4, GD1b and GT1b. However, overall fatty acid compositions of the myelin lipids seemed rather normal.