Mucopolysaccharidosis IIIB, Sanfilippo syndrome B : NAGLU Sequencing

Test Information

NAGLU sequencing is a molecular test used to identify variants in the gene associated with Mucopolysaccharidosis IIIB (MPS IIIB), Sanfilippo syndrome B.

Turnaround Time

3 weeks

CPT Code(s)

81479

Cost

$1,200

Genes

Clinical Information

Sanfilippo syndrome is caused by a defect in one of four enzymes required for the modification and removal of glucosamine residues from heparan sulfate. A defect in one of these four enzymes (types A-D) results in the accumulation of heparan sulfate in the patient�s cells and organs which overtime leads to the clinical phenotype. Patients with Sanfilippo syndrome experience delayed development with a progressively deteriorating mental status. Behavior and sleep problems are common as well as coarse facial features and stiff joints. The four types of Sanfilippo syndrome (A-D) are clinically indistinguishable, thus enzyme testing is recommended as an initial diagnostic test.

Indications

Molecular testing is useful to confirm the diagnosis and to identify the disease causing mutations within a family to allow for carrier testing and prenatal diagnosis.

Methodology

Sanger Sequencing

Detection

Sequencing of the gene will detect mutations in >90% of individuals with enzymatically confirmed Sanfilippo syndrome, Type B.

Specimen Requirements

5 to 7 ml of peripheral blood collected in an EDTA (lavender top) tube is the preferred specimen type. The minimal blood needed for reliable DNA isolation is 3 ml. Extracted DNA, dried blood spots, and saliva are also accepted for this test.

Transport Instructions

The specimen should be kept at room temperature and delivered via overnight shipping. If shipment is delayed by one or two days, the specimen should be refrigerated and shipped at room temperature. Do not freeze the specimen. Samples collected on Friday can be safely designated for Monday delivery.

Prenatal Testing Information

Prenatal diagnosis is available if the familial mutations are known. Additional fees for cell culture and maternal cell contamination may apply. Maternal cell contamination studies are required for all prenatal molecular tests. Contact the laboratory prior to sending a prenatal specimen.

Have Questions Need Support?

Call our laboratory at 1-800-473-9411 or contact one of our Laboratory Genetic Counselors for assistance.
Robin Fletcher, MS, CGC
Kellie Walden, MS, CGC

Molecular Testing, Sanger Sequencing
Meet Makayla Gunn

Meet Makayla Gunn

Makayla was diagnosed with Rett Syndrome in April of 2015 at the age of two.   At about 18 months, we noticed she had started some repetitive hand motions, and her pediatrician was a little concerned that she did not have many words.  She had learned some sign language, and was saying ‘mama’ and ‘dada’, but that was it.  Then she suddenly stopped all of that.  At her 2 year old check-up, the pediatrician referred us to BabyNet, ...

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