Mucolipidosis II/III Plasma Screen

Disease names Mucolipidosis II/ I-Cell disease
Mucolipidosis IIIA/ Pseudo-Hurler Polydystrophy
Clinical info Mucolipidosis II (ML II), also known as I-Cell disease, and Mucolipidosis IIIA (ML IIIA), also known as Pseudo-Hurler Polydystrophy, are lysosomal storage disorders caused by a deficiency of N-acetylglucosamine-1-phosphotransferase (NAPT). ML II is associated with a more severe course including growth failure and failure to thrive, severe developmental delay, coarse facial features, skeletal anomalies and frequent upper respiratory infections. ML II is often lethal in childhood. ML IIIA is associated with a similar, but milder course with a wider spectrum of features and severity. In ML II and ML IIIA, lysosomal hydrolase enzymes are not properly targeted to the lysosome. Therefore, the enzyme activity of multiple lysosomal hydrolases is increased in plasma and other body fluids.
Methodology The activity of 3 lysosomal hydrolases are measured in plasma. The assay uses 4-methylumbelliferyl substrates to measure the activities of alpha-fucosidase, beta-hexosaminidase, and beta-glucuronidase. Prenatal diagnosis and carrier testing via enzyme analysis are not available.
Associated Tests

Mucolipidosis II/III Dried Blood Spot Screen is also available and includes acid sphingomyelinase, alpha-iduronidase, beta-glucosidase, and alpha-mannosidase.

Molecular analysis of the gene for ML II/III (GNPTAB) is also available for identification of the causative mutation within a family, carrier status and prenatal diagnosis.

Specimen Requirements

Enzyme activity can be measured in plasma. Please send 5-10 ml of whole blood in a green top (sodium heparin) tube OR plasma can removed from spun down sample and sent frozen.

In addition, a dried blood spot or blood drawn in an EDTA tube can be used for mucolipidosis II/III molecular analysis and may be sent for DNA banking. Please indicate on the requisition if DNA should be banked for follow-up molecular testing.


Whole blood should be sent overnight at ambient temperature.  Plamsa can be removed once the sample has been drawn and sent frozen on dry ice. Do not freeze whole blood.

Turnaround time 10 days
CPT Codes 82657 (X2)

Whole blood or plasma sample: $400

Contact For further information contact one of our This email address is being protected from spambots. You need JavaScript enabled to view it. at 1-800-473-9411.


acid sphingomyelinase, IDS, beta glucosidase and alpha mannosidase

Biochemical Lab

The Biochemical Lab provides diagnostic and screening tests for a variety of inherited metabolic disorders.

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