Variables in the Laboratory Diagnosis of Fabry's Disease by Measurement of Methylumbelliferyl-?-Galactosidase Activity

[摘要] Assay of methylumbelliferyl-α-galactosidase activity (MUM-α-Galase) in plasma reflects the activity of ceramide trihexosidase and (or) ceramide digalactosidase, which are deficient in Fabry's disease. Intending to institute this assay routinely, we have evaluated substrate stability and concentration, sample stability, heat-inactivation conditions, and normal values. The heat-labile isoenzyme(s) deficient in plasma from patients with Fabry's disease must either be assayed immediately after sampling or the plasma must be stored at or below -50 °C. This heat-labile fraction can be inactivated by incubating a plasma aliquot at 45 °C for 45 min. Normal adult ranges for total and heat-labile MUM-α-Galase are 8.9-31.7 and 7.4-27.4 nmoles of MUM per hour per milliliter of EDTA-treated plasma.

[学科分类] 过敏症与临床免疫学