Clinical use: A Lysosomal storage disease should be suspected in infants or children with growth failure, developmental regression, corneal or lens clouding, hepato-and/or splenomegaly, coarsening facial features and skeletal abnormalities.
Background: Lysosomal enzymes (acid hydrolases) are responsible for breaking down complex chemicals within a cell. The breakdown products are then eliminated from the cell or reused. A deficiency of any one of these enzymes will lead to a “storage disease” which is usually associated with developmental regression. Different storage diseases may have similar clinical features, thus it may be necessary to measure a number of different enzyme activities prior to finding the one deficient in a particular patient. These tests can also be ordered on an individual basis, if desired. The white cell enzyme screen includes the following enzymes – α-fucosidase (Fucosidosis), α-galactosidase (Fabry disease) [Also available as a blood spot test kit available from special biochemistry section] , arylsulphatase A (metachromatic leukodystrophy), α-mannosidase (α-mannosidosis) , β-galactosidase (GM1 gangliosidosis), β-glucosidase (Gaucher disease), β-glucuronidase (Sly syndrome; MPS VII), β-mannosidase (β-mannosidosis).
Reference ranges: Plasma Glycoasparaginase (Aspartylglucosaminuria): 10 – 60
Plasma β-hexosaminidase (Sandhoff′s Disease): 600 – 3500
Plasma β-Mannosidase (β-Mannosidosis): 150 – 1500
Plasma MUGS (Tay – Sachs Disease): 50 – 250
β-Glucuronidase (Sly’s Disease): 100 – 800
β-Galactosidase (GM1 – Gangliosidosis):100 – 400
α-Mannosidase (α-Mannosidosis): 100 – 800
α-Galactosidase (Fabry’s disease): 10 – 50
α-Fucosidase (Fucosidosis): 50 – 250
Acid Esterase (Wolman’s Disease): 350 – 2000
Arylsulphatase A (Metachromatic Leucodystrophy): 50 – 250
β-Glucosidase (Gaucher’s Disease): 1.0 – 5.0
Sphingomyelinase (Niemann-Pick A & B): 1 – 10
Galactocerebrosidase (Krabbe Leucodystropy): 0.8 – 4.0
a-N-Acetylgalactosaminidase (Schindler Disease): 5 – 50
Plasma Chitotriosidase (non-specific marker of storage): 4 – 120
Associated diseases:
Patient preparation: None required
Specimen requirements: EDTA whole blood sample. Send at beginning of working week as enzyme activities will diminish if the sample requires storage over weekend prior to analysis. The sample is referred and must reach Manchester within 72 hours of collection
Turnaround time: 1 week
Additional information:
Referred test: Referred test
Location: Willink Laboratory