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Pompe Disease Sequence Analysis

Pompe disease (glycogen storage disease type II) is an inherited disorder of glycogen metabolism, caused by a deficiency of the enzyme alpha-glucosidase (also called acid-maltase). Pompe disease is a type of lysosomal storage disease. Individuals with Pompe disease are unable to use the glycogen stored in the lysosomes for energy, resulting in the progressive storage of glycogen in the heart, liver, and skeletal muscle. Pompe disease can present in infancy with profound hypotonia, cardiomegaly and cardiomyopathy or later in childhood and adulthood with progressive muscle weakness and respiratory insufficiency. Late onset Pompe disease presenting in the second to seventh decade of life can appear similar to a limb-girdle muscular dystrophy with lower limb proximal weakness.

The alpha-glucosidase enzyme is encoded by the GAA gene. Full gene sequencing will identify two causative mutations in 83-93% of individuals with confirmed reduced or absent enzyme activity. Most mutations are point mutations but deletion of exon 18 accounts for 5-7% of alleles.

Test Name: Pompe Sequencing Analysis
Test Code:
POMPE SEQ
Test Description:
Polymerase Chain Reaction (PCR) followed by sequence analysis of the entire coding region (20 exons) of the GAA gene
Synonyms:
acid maltase deficiency, glycogen storage disease type II, alpha-glucosidase deficiency, GAA deficiency
Indication:
This test is used to provide additional information regarding diagnosed patients or as a secondary confirmation of diagnosis. Sequencing can also be used for carrier testing.
Related Tests: Pompe (alpha-glucosidase, acid maltase)  
This enzyme assay is used to diagnose Pompe disease in a symptomatic individual of any age. This test is not appropriate for determining carrier status or for prenatal diagnosis.

Pompe Known Mutation Analysis  
This test is used for carrier testing at-risk relatives and prenatal testing for confirmed carriers. Mutations must be known.

Clinical Links: Glycogen Storage Disease Type II Gene Review
Availability:
Set up Mon - Fri
Turnaround Time:
2-3 weeks
Methodology:
Polymerase Chain Reaction (PCR) followed by Sequencing
Reference Range:
Interpretive report will be provided
Requisition:
Consent Form:
Sample Requirements: Type
Whole blood: 1-3 ml in EDTA (purple top) or ACD (yellow top)
DNA: 5-10 ug extracted DNA

Processing
Do not spin. Refrigerate blood samples which will not be immediately shipped.

Shipping
Room temperature via overnight shipping.
Samples Received:
Mon – Fri 8:00 am – 5:00 pm PST
Special Considerations:
Cost:
Please e-mail Lab Client Services (labclientservices@seattlechildrens.org) or call at 206-987-2617 with any billing questions
CPT Code:
Please e-mail Lab Client Services (labclientservices@seattlechildrens.org) or call at 206-987-2617 with any billing questions