N-acetyl-alpha-glucosaminidase
Sanfilippo Syndrome B (MPS IIIB): N-Acetyl-Alpha-Glucosaminidase Enzyme Analysis
Key Information
Lab:
TAT:
14 days
Price:
$200
CPT Code(s):
82657
Test Code:
BSFBP, BSFBF, BSFBD
Sanfilippo Syndrome B (MPS IIIB): N-Acetyl-Alpha-Glucosaminidase Enzyme Analysis
This test measures N-acetyl-alpha-glucosaminidase (NAGLU) enzyme activity and can be used as a first-tier test for patients with a clinical suspicion of Sanfilippo syndrome B (Mucopolysaccharidosis IIIB, MPS IIIB). Confirming deficient enzyme activity is the gold standard for diagnosis and can also support interpretation of NAGLU variants and monitor patients undergoing treatment.
Note: Sending fibroblasts will extend turnaround to 28 days.
Sanfilippo syndrome B (MPS IIIB)
Clinical Information
Sanfilippo syndrome is characterized by progressive developmental delay and behavioral problems, with fewer somatic features than other types of mucopolysaccharidosis (MPS) disorders.
The syndrome is caused by a defect in one of four enzymes required for the modification and removal of glucosamine residues from heparan sulfate. Deficiency of any of these enzymes (types A–D) leads to accumulation of heparan sulfate in cells and organs, resulting in the clinical phenotype. Patients typically exhibit delayed development with progressive cognitive decline, behavioral and sleep disturbances, coarse facial features, and joint stiffness. Because the four types (A–D) are clinically indistinguishable, enzyme testing is recommended as an initial diagnostic step.
Technical Information
4-methylumbelliferyl (4-MU) substrate
Specimen Requirements
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.
Fibroblasts: Tissue sample should be stored in sterile culture media; cultured fibroblasts should be sent in two T25 flasks. Do NOT place tissue in formalin or formaldehyde. Do not freeze tissue.
Plasma: A minimum of 3 mLwhole 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.
Fibroblasts: Ship tissue sample or cultured fibroblasts at ambient temperature
Plasma: Plasma should be frozen after collection and shipped frozen, preferably on dry ice. Whole blood should be shipped at ambient temperature.
Connect With Our Experts
Call 1-800-473-9411 to speak with our team of laboratory genetic counselors for questions or additional information.
Robin Fletcher, MS, CGC
Falecia Thomas, MS, CGC
Alex Finley, MS, CGC