Globoid cell leukodystrophy: deficiency of lactosyl ceramide beta-galactosidase.

Activity of lactosyl ceramide beta-galactosidase (beta-D-galactoside galactohydrolase, EC 3.2.1.23) was found to be extremely low in enzyme preparations from liver, brain, and cultured skin fibroblasts from patients with Krabbe's disease. Leukocytes from one set of parents had enzyme levels approximately half those measured in control leukocytes. The low activity observed for this galactolipid hydrolase is the fourth enzymatic deficiency noted for this genetic disease. Beta-galactosidase activity toward galactocerebroside, psychosine, and monogalactosyl diglyceride is also low in patients with Krabbe's disease. Other lysosomal enzymes measured were found to be in the normal range. This enzymatic defect may provide a better explanation for the pathological and chemical findings previously reported for this syndrome.