Congenital Disorders of Glycosylation (CDG) Panel (Types Ia, Ib, and Ic)

Summary and Pricing

Test Method

Exome Sequencing with CNV Detection
Test Code Test Copy Genes Gene CPT Codes Copy CPT Codes
10601 ALG6 81479,81479 Order Options and Pricing
MPI 81405,81479
PMM2 81479,81479
Test Code Test Copy Genes Panel CPT Code Gene CPT Codes Copy CPT Code Base Price
10601Genes x (3)81479 81405(x1), 81479(x5) $890 Order Options and Pricing

Pricing Comments

We are happy to accommodate requests for testing single genes in this panel or a subset of these genes. The price will remain the list price. If desired, free reflex testing to remaining genes on panel is available.

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 backbone).

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

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

  • Kym Bliven, PhD

Clinical Features and Genetics

Clinical Features

Congenital disorders of glycosylation (CDG) are a genetically heterogeneous group of disorders caused by defective synthesis of asparagine (N)-linked glycans. Abnormalities in these glycoconjugates cause disturbances in metabolism, cell recognition, cell adhesion, protease resistance, host defense, cell migration, and antigenicity (Marquardt and Denecke. Eur J Pediat 162:359-379, 2003). Consequently, clinical presentations are characterized by multisystem involvement. Individuals with CDG Ia (OMIM #212065) have cerebellar hypoplasia, dysmorphic facies, coagulopathy, strabismus, psychomotor retardation, and sometimes unusual fat distribution and inverted nipples (de Lonlay et al. J Med Genet 38:14-19, 2001; Sparks and Krasnewich GeneReviews 2005). Presentation and clinical course can be highly variable, and three stages (infantile multisystem stage, late infantile and childhood ataxia-mental retardation stage, adult stable disability stage) have been delineated. Individuals with CDG Ib (OMIM #602579) exhibit diarrhea, protein-losing enteropathy, profound hypoglycemia, coagulopathy, and fibrotic liver disease (Jaeken et al. Am J Hum Genet 62:1535-1539, 1998). Patients are not dysmorphic and do not have cerebellar hypoplasia or unusual fat distribution. CDG Ib is treatable with oral mannose (Niehues at al. J Clin Invest 101:1414-1420, 1998). Individuals with CDG Ic (OMIM #603147) exhibit neurological symptoms including hypotonia, developmental delay, strabismus, and seizures. Clinical features of CDG Ic overlap both types Ia and Ib; however, symptoms are generally not as severe as in type Ia, and multi-organ involvement is not observed. Minimal protein-losing enteropathy and minimal liver disease of CDG Ic can often differentiate this type from CDG Ib. Cerebellar hypoplasia, a consistent finding in type Ia, is not seen in type Ic patients (Grunewald et al. Pediat Res 52:618-624, 2002).

Genetics

All CDGs exhibit autosomal recessive inheritance. Thirteen forms of CDG have been characterized at the molecular level, but only three, CDG Ia, CDG Ib, and CDG Ic, have been reported in more than a few individual patients. CDG Ia is the most common form with ~400 cases reported worldwide, followed by CDG 1b and CDG Ic, each with approximately 20 cases. Variants in these three genes are most commonly missense variants, and they are distributed throughout the coding regions.

Clinical Sensitivity - Sequencing with CNV PGxome

In cases with demonstrated reduced phosphomannomutase or mannosephosphate isomerase activity plus diagnostic serum transferrin glycoforms, PMM2 and MPI sequencing, respectively, is nearly 100% sensitive (Sparks and Krasnewich, GeneReviews 2005). Due to the low incidence of CDG Ic and lack of enzyme assay, test sensitivity for ALG6 sequencing is difficult to estimate.

Testing Strategy

This test is performed using Next-Gen sequencing with additional Sanger sequencing as necessary.

This panel provides 100% coverage of all coding exons of the genes 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 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 clinical and biochemical findings consistent with CDG.

Genes

Official Gene Symbol OMIM ID
ALG6 604566
MPI 154550
PMM2 601785
Inheritance Abbreviation
Autosomal Dominant AD
Autosomal Recessive AR
X-Linked XL
Mitochondrial MT

Related Test

Name
PGxome®

Citations

  • de Lonlay, P., et.al. (2001). "A broad spectrum of clinical presentations in congenital disorders of glycosylation I: a series of 26 cases." J Med Genet 38(1): 14-9. PubMed ID: 11134235
  • Grunewald, S., et.al. (2002). "Congenital disorders of glycosylation: a review." Pediatr Res 52(5): 618-24. PubMed ID: 12409504
  • Jaeken, J., et.al. (1998). "Phosphomannose isomerase deficiency: a carbohydrate-deficient glycoprotein syndrome with hepatic-intestinal presentation." Am J Hum Genet 62(6): 1535-9. PubMed ID: 9585601
  • Marquardt, T., Denecke, J. (2003). "Congenital disorders of glycosylation: review of their molecular bases, clinical presentations and specific therapies." Eur J Pediatr 162(6): 359-79. PubMed ID: 12756558
  • Niehues, R., et.al. (1998). "Carbohydrate-deficient glycoprotein syndrome type Ib. Phosphomannose isomerase deficiency and mannose therapy." J Clin Invest 101(7): 1414-20. PubMed ID: 9525984
  • Susan E Sparks, Donna M Krasnewich (2008). "Congenital Disorders of Glycosylation Overview."

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

PGxome (Exome) Sequencing Panel

PGnome (Genome) Sequencing Panel

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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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