Sanfilippo Syndrome Panel (MPS Types III A, B, C, and D) – Enzyme Analysis
|Disease name||Sanfilippo syndrome, Types A, B, C and D (MPS IIIA, IIIB, IIIC, and IIID)|
|Enzyme Name||Sanfilippo, Type A - Heparan-N-sulfatase
Sanfilippo, Type B - N-acetyl-alpha-D-glucosaminidase
Sanfilippo, Type C - Acetyl CoA: glucosamine N acetyl transferase
Sanfilippo, Type D - N-acetyl glucosamine-6-sulfatase (currently unavailable)
|Clinical info||Sanfilippo syndrome is characterized by progressive developmental delay and behavioral problems. These patients have fewer of the somatic concerns seen in other types of MPS disorders.|
|Indications||There are four enzymatically distinct forms of Sanfilippo syndrome with significant clinical overlap. Enzymatic testing is necessary to further distinguish between the following four types. These four enzymes are required for the modification and removal of glucosamine residues from heparan sulfate. These defects result in the accumulation of heparan sulfate in the patient’s cells and organs which overtime leads to the clinical phenotype. Enzyme analysis for each type of Sanfilippo syndrome may be ordered individually or as a panel. Prenatal diagnosis or carrier testing via enzyme analysis is not available.|
|Methodology||Assay will employ a 4-methylumbelliferyl substrate.|
In all four types, urinary excretion of heparan sulfate is seen which can be assessed via mucopolysaccharide electrophoresis. Molecular analysis for any of the genes associated with Sanfilippo syndrome is available.
Molecular testing is useful to confirm the diagnosis and to identify the disease causing mutation within a family to allow for carrier testing and prenatal diagnosis.
|Specimen Requirements||Fibroblasts or a sodium heparin (green top) tube of peripheral blood. Leukocytes are used for enzyme analysis for Sanfilippo A, C and D. Plasma is used for enzyme analysis for Sanfilippo B. If ordering the panel, 7-10 ml of whole blood collected in a sodium heparin (green top) tube is acceptable from which the plasma can be pulled off for type B and then leukocytes can be isolated for types A, C and D. Enzymes can also be measured via fibroblasts for all four types.|
|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 tube and shipped overnight.|
|Turnaround time||14 days
Cell culture can take 1-4 weeks and may lengthen turnaround time.
|CPT Codes||Single enzyme: 82657
Panel of Sanfilippo A, B, C and D: 82657(x4)
|Cost||$200 for a single enzyme
$800 for full panel
The Biochemical Lab provides diagnostic and screening tests for a variety of inherited metabolic disorders.