White-Cell β-Galactosidase Activity

The differential diagnosis between patients with generalized gangliosidosis and several types of genetic mucopolysaccharidoses can be a problem. In both groups of disorders the lysosomal enzyme β-galactosidase has been shown to be deficient in liver, spleen, kidney, brain and skin.^{1 2 3} The diagnosis of G_M1 gangliosidosis is based on clinical phenotype coupled with a normal concentration of derinatan and heparin sulfate in the urine and the absence of β-galactosidase in the liver. Recently Sloan⁴ reported a case with deficiency of this enzyme in cultured fibroblasts. Since fibroblasts and leukocytes have similar embryologic origins, it seemed a.