A microassay for Gaucher's disease.

We report a new assay for the detection of individuals heterozygous and homozygous for Gaucher's disease which requires relatively small samples of whole blood (0.3 ml), and which determines 4-methylumbelliferyl-beta-D-glucopyranoside:beta-glucosidase activity under conditions optimal for the determination of leukocyte glucocerebroside:beta-glucocereborsidase activity. The procedure involves the preparation of a leukocyte pellet from 50 mul of whole blood by hypotonic lysis of erythrocytes, followed by assay of beta-glucosidase activity at pH 5.5 in the presence of sodium taurocholate (0.6 g/100 ml). The methods described may also prove to be useful for the diagnosis of other diseases of enzyme deficiency which use fluorogenic substrates and leukocytes as a source of enzyme, such as Fabry's disease, Tay-Sachs disease, and generalized gangliosidosis.