Chemical diagnosis of Fabry's disease by fluorometric assay and fast atom bombardment/mass spectrometry.

We report the results of a fluorometric assay for alpha-galactosidase A (EC.3.2.1.22) in plasma and leukocytes, and fast atom bombardment/mass spectrometry (FAB/MS) analysis of glycosphingolipids in urine sediments from a patient with Fabry's disease. In plasma, this patient had only 5.0% of the normal amount of alpha-galactosidase A, and his brother and mother had 11.0% and 25.0%, respectively. In leukocytes, the activities were below 8.0%. Glycosphingolipids from urine sediments were partially purified using a Sep-Pack C18 cartridge. The chemical diagnosis of Fabry's disease can be made more rapidly and accurately using fluorometric and FAB/MS analyses.