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Congenital Disorders of Glycosylation, Type Ig (CDG Ig) via the ALG12 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
ALG12 81479 81479,81479 $990
Test Code Test Copy Genes Test CPT Code Gene CPT Codes Copy CPT Code Base Price
8535ALG1281479 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.


Genetic Counselors


  • Hongjie Chen

Clinical Features and Genetics

Clinical Features

Congenital disorders of glycosylation (CDGs) are a clinically heterogeneous group of inborn errors of metabolism that are characterized by defects in protein or lipid glycosylation, a form of post-translational modification. Consequently, the majority of these disorders demonstrate multi-system involvement. These disorders can be further differentiated into several categories depending upon what part of the glycosylation pathway has been disrupted: protein N-linked protein glycosylation defects, which are the most common; O-linked protein glycosylation defects; glycolipid and glycosylphosphatidylinositol (GPI) anchor defects; or multi-pathway defects (Brasil et al. 2018. PubMed ID: 29702557; Jaeken. 2017. PubMed ID: 28484880; Scott et al. 2014. PubMed ID: 24831587).

Approximately 10 cases of CDG Ig, an N-linked glycosylation defect, have been reported in the literature to date, and all were diagnosed in early infancy (Haeuptle et al. 2009. PubMed ID: 19862844; Normand et al. 2018. PubMed ID: 30266093; Retterer et al. 2016. PubMed ID: 26633542; Murali et al. 2014. PubMed ID: 25019053). Affected individuals commonly present with feeding difficulties, psychomotor delay, short stature, hypotonia, microcephaly, facial dysmorphism, inverted nipples, thrombocytopenia, low IgG, and/or intermittent elevation of liver transaminases. Males may exhibit micropenis and/or hypospadias (Kranz et al. 2007. PubMed ID: 17506107; Eklund et al. 2005. PubMed ID: 15639192).

In the most severe cases, skeletal involvement and/or structural brain abnormalities have been reported. Several probands presented with talipes equinovarus and ulnar deviation at the wrists (Kranz et al. 2007. PubMed ID: 17506107; Murali et al. 2014. PubMed ID: 25019053). Clinical features of other affected individuals included hypoplasia of the corpus callosum or ventricle enlargement (Kranz et al. 2007. PubMed ID: 17506107; Di Rocco et al. 2005. PubMed ID: 16435218).


Congenital disorder of glycosylation type Ig is inherited in an autosomal recessive manner. Most of the causative variants reported in this gene to date are missense; however, one nonsense variant and four small frameshift deletions have also been described (Human Gene Mutation Database).

The ALG12 gene encodes a mannosyltransferase that catalyzes the transfer of the eighth mannose from dolichol-P-Man to the dolichol-linked oligosaccharide (Haeuptle et al. 2009. PubMed ID: 19862844).

Clinical Sensitivity - Sequencing with CNV PGxome

Due to the low incidence of this disorder clinical sensitivity cannot be estimated. All coding and non-coding regions of the ALG12 gene that harbor causative variants reported in the Human Gene Mutation Database (HGMD; http://www.hgmd.cf.ac.uk/) as of 08/06/2019 are covered in this test.

Testing Strategy

This test provides full coverage of all coding exons of the ALG12 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

Candidates for this test include individuals with clinical symptoms consistent with CDG Ig or individuals with a CDG-I pattern upon isoelectric focusing of serum transferrin, particularly after more common forms of CDG-I have been ruled out (particularly PMM2 gene sequencing) (Kranz et al. 2007. PubMed ID: 17506107). This test may also be considered for the reproductive partners of individuals who carry pathogenic variants in ALG12.


Official Gene Symbol OMIM ID
ALG12 607144
Inheritance Abbreviation
Autosomal Dominant AD
Autosomal Recessive AR
X-Linked XL
Mitochondrial MT


Name Inheritance OMIM ID
Congenital Disorder Of Glycosylation Type 1G AR 607143

Related Test

Congenital Disorders of Glycosylation (CDG) Panel (Types Id, Ie, If, Ig, Ih, Ii)



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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View Ordering Instructions

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2) Select Additional Test Options

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