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 total hexosaminidase, beta-glucuronidase and alpha-fucosidase. Prenatal diagnosis and carrier testing via enzyme analysis are not available.|
|Associated Tests||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.|
Enzyme activity can be measured in plasma or dried blood spots. For 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 over 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.
For a dried blood spot: When the sample has dried 3-4 hours, fold cover at score line, over sample, and tuck into flap. Samples should be placed in the mail within 24 hours of collection. Overnight shipping is preferred.
|Turnaround time||10 days|
|CPT Codes||82657 (X2)|
Whole blood or plasma sample: $400
Dried Blood Spot Analysis: A 50% discount will be applied for enzyme analysis from a dried blood spot reducing the price to $200.
The Biochemical Lab provides diagnostic and screening tests for a variety of inherited metabolic disorders.