Morquio syndrome, Types A and B - Enzyme Analysis
| Disease name | Morquio syndrome, Types A and B (MPS IVA and B) | |
| Enzyme Name | Morquio, Type A is caused by deficiency of N-acetyl-galactosamine-6-sulfatase. Morquio, Type B is caused by a deficiency of beta galactosidase. |
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| Clinical info | Morquio syndrome is characterized by short stature and trunk, large head, mildly coarse facies, widely spaced teeth, corneal clouding, a bell-shaped chest, vertebral anomalies, joint stiffness and kyphoscoliosis. Other features may include inguinal hernia, hepatomegaly and hearing loss. There is a wide spectrum of those affected ranging from mild to severe. Intelligence is typically not affected. | |
| Indications | Morquio, Types A and B can have significant clinical overlap, thus enzyme analysis is necessary to distinguish between the two types. These enzymes are needed for the modification and removal of keratin sulfate. Enzyme analysis for each type of Morquio syndrome may be ordered individually or as a panel. Prenatal diagnosis and carrier testing via enzyme analysis are not available. | |
| Associated Tests | Urinary excretion of keratan sulfate is seen which can be assessed via MPS electrophoresis. Beta galactosidase is also on the hydrops enzyme panel. | |
| Methodology | Assays employ a 4-methylumbelliferyl substrate. | |
| Specimen Requirements | Enzyme activity can be measured in leukocytes or cultured fibroblasts. | |
| Transport | Please contact the laboratory before transporting tissue for enzyme assay. Fresh tissue for culture should be sent by courier or 24-hour delivery. Blood should be collected in a sodium heparin (green top) tube and shipped overnight. | |
| Turnaround time | 14 days Cell culture can take 1-4 weeks and may lengthen turnaround time. |
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| CPT Codes | Single enzyme: 82657 Panel of Morquio A and B: 82657(x2) |
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| Cost | $200 for a single enzyme; $400 for both enzymes | |
| Contact | For further information contact Kellie King, MS or Tim Wood, PhD at 1-800-473-9411 | |
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Kellie King, MS, CGC
Biochemical Lab
The Biochemical Lab provides diagnostic and screening tests for a variety of inherited metabolic disorders.