Aspartylglucosaminuria: Aspartyglucosaminidase Enzyme Analysis

Clinical Information

Aspartylglucosaminuria is a rare lysosomal storage disorder (LSD) characterized primarily by progressive intellectual disability. Patients with this disorder typically have some skeletal and connective tissue abnormalities, and mildly coarse features. Frequent infections, behavioral changes, cardiomyopathy, and changes in the facial skin have also been reported in association with aspartylglucosaminuria.

Technical Information

Enzyme activity is measured using a 4-methylcoumarin substrate.

Specimen Requirements

• Accepted sample types for this test include dried blood spots (DBS), leukocytes, and plasma.
• DBS: Approximately 75 uL of blood should be applied to each of the five circles on filter paper dried blood spot card. Allow blood to dry for at least 4 hours before shipping.
• Leukocytes: A minimum of 5 mL whole blood (7-10 mL preferred) collected in a sodium heparin tube
• Plasma: A minimum of 3 mL whole blood collected in a sodium heparin tube; or blood can be centrifuged and a minimum of 1 mL plasma removed and sent for analysis.

Transport Instructions

• DBS: Ship DBS card at ambient temperature
• Leukocytes: Whole blood should be shipped at ambient temperature. If leukocytes are being isolated at another laboratory, the pellet should be frozen after specimen processing and shipped frozen on dry ice.
• Plasma: Plasma should be frozen after collection and shipped frozen, preferably on dry ice. Whole blood should be shipped at ambient temperature.