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Glycogen Storage Disease Type IV via the GBE1 Gene

Summary and Pricing

Test Method

Sequencing and CNV Detection via NextGen Sequencing using PG-Select Capture Probes
Test Code Test Copy GenesTest CPT Code Gene CPT Codes Copy CPT Codes Base Price
5413 GBE1 81479 81479,81479 $640 Order Options and Pricing
Test Code Test Copy Genes Test CPT Code Gene CPT Codes Copy CPT Code Base Price
5413GBE181479 81479,81479 $640 Order Options and Pricing

Pricing Comments

This test is also offered via our exome backbone with CNV detection (click here). The exome-based test may be higher priced, but permits reflex to the entire exome or to any other set of clinically relevant genes.

An additional 25% charge will be applied to STAT orders. STAT orders are prioritized throughout the testing process.

Turnaround Time

18 days on average for standard orders or 13 days on average for STAT orders.

Please note: Once the testing process begins, an Estimated Report Date (ERD) range will be displayed in the portal. This is the most accurate prediction of when your report will be complete and may differ from the average TAT published on our website. About 85% of our tests will be reported within or before the ERD range. We will notify you of significant delays or holds which will impact the ERD. Learn more about turnaround times here.

Targeted Testing

For ordering sequencing of targeted known variants, go to our Targeted Variants page.

EMAIL CONTACTS

Genetic Counselors

Geneticist

  • Maxime Cadieux-Dion, PhD

Clinical Features and Genetics

Clinical Features

Glycogen storage disease (GSD) type IV (OMIM 232500), also known as Andersen disease, is a rare, severe disorder caused by a deficiency of glycogen branching enzyme encoded by the GBE1 gene. Clinical features for GSD type IV vary widely. Some research groups bin patients into two groups: those presenting with liver disease and those presenting with neuromuscular symptoms (see OMIM; http://www.emedicine.com/ped/topic97.htm; Bao et al. J Clin Invest 97:941-948, 1996; and Bruno et al. Neurology 63:1053-1058, 2004). In most liver disease cases, failure to thrive is observed during the first 18 months. Hepatosplenomegaly and liver cirrhosis then develop, leading to death by 5 years. Non-progressive hepatic forms have also been described. The neuromuscular forms of the disease range from a lethal neonatal form with hypotonia, muscle wasting, and cardiomyopathy to an adult onset form, sometimes called adult polyglucosan body disease (APBD; OMIM 263570) characterized by neurodegenerative features. For additional information, see the web sites for the Association for Glycogen Storage Disease (www.agsdus.org) and the APBD Research Foundation (www.apbdrf.org).

Genetics

Both GSD Type IV and APBD are autosomal recessive disorders. Variants in the GBE1 gene are the only known cause of both of these disorders. About 20 different causative variants have been reported. The variants are about equally split between missense and nonsense or frameshift. Variants are located throughout the length of the gene. APBD appears to be more common in people with Ashkenazi Jewish ancestry than other populations. Few connections have been made between genotype and phenotype, although there are indications that some missense variants may lead to partial enzymatic activity and less severe phenotypes.

Clinical Sensitivity - Sequencing with CNV PG-Select

Sensitivity of this test has not been reported but should be relatively high for patients with low enzyme activity.

Testing Strategy

This test provides full coverage of all coding exons of the GBE1 gene plus 10 bases of flanking noncoding DNA in all available transcripts along with other non-coding regions in which pathogenic variants have been identified at PreventionGenetics or reported elsewhere. We define full coverage as >20X NGS reads or Sanger sequencing.

This testing also includes coverage for the deep intronic variant c.2053-3358_2053-3350delinsTGTTTTTTACATGACAGGT (Akman et al. 2015).

Indications for Test

All patients with symptoms of GSD type IV are candidates for this test. Many of those tested will have reduced glycogen branching activity determined by enzyme assay. This test may also be considered for the reproductive partners of individuals who carry pathogenic variants in GBE1.

Gene

Official Gene Symbol OMIM ID
GBE1 607839
Inheritance Abbreviation
Autosomal Dominant AD
Autosomal Recessive AR
X-Linked XL
Mitochondrial MT

Citations

  • Akman H.O. et al. 2015. JAMA Neurology. 72: 441-5. PubMed ID: 25665141
  • Bao Y. et al. 1996. The Journal of Clinical Investigation. 97: 941-8. PubMed ID: 8613547
  • Bruno C. et al. 2004. Neurology. 63: 1053-8. PubMed ID: 15452297

Ordering/Specimens

Ordering Options

We offer several options when ordering sequencing tests. For more information on these options, see our Ordering Instructions page. To view available options, click on the Order Options button within the test description.

myPrevent - Online Ordering

  • The test can be added to your online orders in the Summary and Pricing section.
  • Once the test has been added log in to myPrevent to fill out an online requisition form.
  • PGnome sequencing panels can be ordered via the myPrevent portal only at this time.

Requisition Form

  • A completed requisition form must accompany all specimens.
  • Billing information along with specimen and shipping instructions are within the requisition form.
  • All testing must be ordered by a qualified healthcare provider.

For Requisition Forms, visit our Forms page


Specimen Types

Specimen Requirements and Shipping Details

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ORDER OPTIONS

View Ordering Instructions

1) Select Test Method (Backbone)


1) Select Test Type


2) Select Additional Test Options

STAT and Prenatal Test Options are not available with Patient Plus.

No Additional Test Options are available for this test.

Note: acceptable specimen types are whole blood and DNA from whole blood only.
Total Price: $
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