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Congenital Disorder of Glycosylation, Type Iu and Secondary Dystroglycanopathy via the DPM2 Gene

Summary and Pricing

Test Method

Exome Sequencing with CNV Detection
Test Code Test Copy GenesTest CPT Code Gene CPT Codes Copy CPT Codes Base Price
DPM2 81479 81479,81479 $990
Test Code Test Copy Genes Test CPT Code Gene CPT Codes Copy CPT Code Base Price
9083DPM281479 81479,81479 $990 Order Options and Pricing

Pricing Comments

Our favored testing approach is exome based NextGen sequencing with CNV analysis. This will allow cost effective reflexing to PGxome or other exome based tests. However, if full gene Sanger sequencing is desired for STAT turnaround time, insurance, or other reasons, please see link below for Test Code, pricing, and turnaround time information. If the Sanger option is selected, CNV detection may be ordered through Test #600.

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

Click here for costs to reflex to whole PGxome (if original test is on PGxome Sequencing platform).

Click here for costs to reflex to whole PGnome (if original test is on PGnome Sequencing platform).

The Sanger Sequencing method for this test is NY State approved.

For Sanger Sequencing click here.

Turnaround Time

3 weeks on average for standard orders or 2 weeks 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

  • Angela Gruber, PhD

Clinical Features and Genetics

Clinical Features

Congenital disorders of glycosylation (CDGs) are a genetically heterogeneous group of disorders caused by defective synthesis of N-linked glycans. Abnormalities in these glycoconjugates cause disturbances in metabolism, cell recognition, cell adhesion, protease resistance, host defense, cell migration, and antigenicity. Clinical presentations are characterized by multisystem involvement (Marquardt and Denecke 2003; Jaeken and Péanne 2017). Dystroglycan is the central component of the muscle dystrophin-glycoprotein complex (Michele 2003). DAG1 encodes the alpha and beta subunits of dystroglycan. Both subunits undergo modification by N- and O-linked glycosylation; however, alpha-dystroglycan undergoes extensive O-linked glycosylation (Ibraghimov-Beskrovnaya et al. 1993). The glycosylation status of dystroglycan is critical for ligand binding and pathogenesis (Barresi and Campbell 2006).

DPM2 pathogenic variants have been reported in at least two unrelated families. Three children have been desribed with severe hypotonia, congenital contractures, elevated creatine kinase levels, microcephaly, seizures, and profound developmental delay (Barone R. et al. 2012). These children had elevated levels of Dol-PP-GlcNAc2Man5 and one also had a muscle biopsy with reduced levels of glycosylated alpha-dystroglycan. DPM2-associated CDG has been classified as type Iu.

Genetics

Congenital disorders of glycosylation and the dystroglycan associated muscular dystrophies all exhibit autosomal recessive inheritance. CDG type Iu is inherited in an autosomal recessive manner due to pathogenic variants in DPM2, located on chromosome 9q34.13. The DPM2 gene encodes the dolichyl-phosphate mannosyltransferase-2 protein which is a subunit of the heterotrimeric dolichol-phosphate-mannose synthase complex. This subunit is required for enzyme activity and is thought to possibly stabilize the DPM3 protein. Pathogenic variants reported thus far include a missense and a splicing variant (Barone et al. 2012; Human Gene Mutation Database).

Clinical Sensitivity - Sequencing with CNV PGxome

Many types of congenital disorders of glycosylation (CDG) exist and may be difficult to distinguish from DPM2-related CDG. The clinical sensitivity is uncertain, as only two families with DPM2-related CDG have been reported thus far, indicating that DPM2 is likely a rare cause. Analytical sensitivity should be high as all reported pathogenic variants are detectable by sequencing.

To date, no large deletions or duplications involving the DPM2 gene have been reported (Human Gene Mutation Database).

Testing Strategy

This test provides full coverage of all coding exons of the DPM2 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. PGnome panels typically provide slightly increased coverage over the PGxome equivalent. PGnome sequencing panels have the added benefit of additional analysis and reporting of deep intronic regions (where applicable).

Dependent on the sequencing backbone selected for this testing, discounted reflex testing to any other similar backbone-based test is available (i.e., PGxome panel to whole PGxome; PGnome panel to whole PGnome).

Indications for Test

Individuals with biochemical findings consistent with CDG, and clinical and immuno-histochemical findings consistent with secondary dystroglycanopathy. This test may also be considered for the reproductive partners of individuals who carry pathogenic variants in DPM2.

Gene

Official Gene Symbol OMIM ID
DPM2 603564
Inheritance Abbreviation
Autosomal Dominant AD
Autosomal Recessive AR
X-Linked XL
Mitochondrial MT

Disease

Name Inheritance OMIM ID
Congenital Disorder of Glycosylation Type Iu AR 615042

Citations

  • Barone R. et al. 2012. Annals of Neurology. 72: 550-8. PubMed ID: 23109149
  • Barresi R., Campbell K.P. 2006. Journal of Cell Science. 119: 199-207. PubMed ID: 16410545
  • Human Gene Mutation Database (Bio-base).
  • Ibraghimov-Beskrovnaya O. et al. 1993. Human Molecular Genetics. 2: 1651-7. PubMed ID: 8268918
  • Jaeken J., Péanne R. 2017. Journal of Inherited Metabolic Disease. 40: 569-86. PubMed ID: 28484880
  • Marquardt T., Denecke J. 2003. European Journal of Pediatrics. 162: 359-79. PubMed ID: 12756558
  • Michele D.E. 2003. Journal of Biological Chemistry. 278: 15457-60. PubMed ID: 12556455

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

If ordering a Duo or Trio test, the proband and all comparator samples are required to initiate testing. If we do not receive all required samples for the test ordered within 21 days, we will convert the order to the most effective testing strategy with the samples available. Prior authorization and/or billing in place may be impacted by a change in test code.


Specimen Types

Specimen Requirements and Shipping Details

PGxome (Exome) Sequencing Panel

PGnome (Genome) Sequencing Panel

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ORDER OPTIONS

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View Ordering Instructions

1) Select Test Method (Platform)


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2) Select Additional Test Options

No Additional Test Options are available for this test.

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