Elevation of serum beta-hexosaminidase and alpha-D-mannosidase in type 2 Gaucher disease: a clinical and biochemical study.

We report a case of a black infant who died at 9 months of age with clinical and pathological findings consistent with the acute neuronopathic form of Gaucher disease (Type 2). Analysis of peripheral blood platelets obtained from this child demonstrated very low levels of beta-glucosidase activity. beta-hexosaminidase (HEX) activity in the serum, however, was 30 times greater than the level in control sera and 15 times greater than the level observed in individuals affected with the chronic form of Gaucher disease (Type 1). Similarly, alpha-D-mannosidase (MANN) activity in the proband's serum was significantly elevated when compared with controls, and chronic Gaucher disease patients. We postulate that the cause of the elevation of these lysosomal enzymes is similar to the cause of elevation in Type 1 individuals but that patients with Type 2 Gaucher disease have a more serious cellular defect.