Biochemical studies of the late infantile form of metachromatic leukodystrophy.

Biochemical studies from a patient with the late infantile form of metachromatic leukodystrophy are presented. Since the autopsy was performed soon after death, viable cells were isolated from brain. The purified cells had altered densities and unusual appearances. The cells when placed in culture were able to incorporate radiolabeled substrates into cerebrosides, indicating that some of the cells were of oligodendroglial origin. Myelin was isolated using several different methods, and the degree of abnormality appeared to be dependent upon the method of isolation. Nonetheless, MLD myelin, while still retaining its characteristic-morphology, had increased levels of sulfatides (two to four times that normally found). Other membrane subfractions were isolated that were not present in control tissue and that were more abnormal in composition than myelin. Finally, the glycoproteins in MLD tissue also appeared to be altered. There were losses in MLD myelin glycoproteins that bind to Concanavalin A (Con A) and additional prominent glycoproteins that bind to wheat germ agglutinin.