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
Turnaround time: 1 week
Additional information:
Referred test: Referred test
Location: Willink Laboratory