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HelpTest ID: CDGGP Congenital Disorders of Glycosylation Gene Panel, Varies
Ordering Guidance
The recommended first-tier test to screen for congenital disorders of glycosylation (CDG) is a biochemical test that analyzes transferrin and apolipoprotein CIII; order CDG / Carbohydrate Deficient Transferrin for Congenital Disorders of Glycosylation, Serum.
Customization of this panel and single gene analysis for any gene present on this panel are available. For more information see CGPH / Custom Gene Panel, Hereditary, Next-Generation Sequencing, Varies
Shipping Instructions
Specimen preferred to arrive within 96 hours of collection.
Specimen Required
Patient Preparation: A previous bone marrow transplant from an allogenic donor will interfere with testing. Call 800-533-1710 for instructions for testing patients who have received a bone marrow transplant.
Submit only 1 of the following specimens:
Specimen Type: Whole blood
Container/Tube:
Preferred: Lavender top (EDTA) or yellow top (ACD)
Acceptable: Any anticoagulant
Specimen Volume: 3 mL
Collection Instructions:
1. Invert several times to mix blood.
2. Send whole blood specimen in original tube. Do not aliquot.
Specimen Stability Information: Ambient (preferred) 4 days/Refrigerated 14 days
Specimen Type: Skin biopsy
Supplies: Fibroblast Biopsy Transport Media (T115)
Container/Tube: Sterile container with any standard cell culture media (eg, minimal essential media, RPMI 1640). The solution should be supplemented with 1% penicillin and streptomycin (Eagle's minimum essential medium with 1% penicillin and streptomycin).
Specimen Volume: 4-mm punch
Specimen Stability Information: Refrigerated (preferred)/Ambient
Additional Information: A separate culture charge will be assessed under CULFB / Fibroblast Culture for Biochemical or Molecular Testing. An additional 3 to 4 weeks is required to culture fibroblasts before genetic testing can occur.
Specimen Type: Cultured fibroblast
Container/Tube: T-25 flask
Specimen Volume: 2 Flasks
Collection Instructions: Submit confluent cultured fibroblast cells from a skin biopsy from another laboratory. Cultured cells from a prenatal specimen will not be accepted.
Specimen Stability Information: Ambient (preferred)/Refrigerated (<24 hours)
Additional Information: A separate culture charge will be assessed under CULFB / Fibroblast Culture for Biochemical or Molecular Testing. An additional 3 to 4 weeks is required to culture fibroblasts before genetic testing can occur.
Specimen Type: Blood spot
Supplies: Card-Blood Spot Collection (Filter Paper) (T493)
Container/Tube:
Preferred: Collection card (Whatman Protein Saver 903 Paper)
Acceptable: PerkinElmer 226 (formerly Ahlstrom 226) filter paper, or blood spot collection card
Specimen Volume: 5 Blood spots
Collection Instructions:
1. An alternative blood collection option for a patient older than 1 year is a fingerstick. For detailed instructions, see How to Collect Dried Blood Spot Samples.
2. Let blood dry on the filter paper at ambient temperature in a horizontal position for a minimum of 3 hours.
3. Do not expose specimen to heat or direct sunlight.
4. Do not stack wet specimens.
5. Keep specimen dry.
Specimen Stability Information: Ambient (preferred)/Refrigerated
Additional Information:
1. Due to lower concentration of DNA yielded from blood spot, it is possible that additional specimen may be required to complete testing.
2. For collection instructions, see Blood Spot Collection Instructions.
3. For collection instructions in Spanish, see Blood Spot Collection Card-Spanish Instructions (T777).
4. For collection instructions in Chinese, see Blood Spot Collection Card-Chinese Instructions (T800).
Specimen Type: Saliva
Patient Preparation: Patient should not eat, drink, smoke, or chew gum 30 minutes prior to collection.
Supplies: Saliva Swab Collection Kit (T786)
Specimen Volume: 1 Swab
Collection Instructions: Collect and send specimen per kit instructions.
Specimen Stability Information: Ambient 30 days
Additional Information: Due to lower concentration of DNA yielded from saliva, it is possible that additional specimen may be required to complete testing.
Forms
1. New York Clients-Informed consent is required. Document on the request form or electronic order that a copy is on file. The following documents are available:
-Informed Consent for Genetic Testing (T576)
-Informed Consent for Genetic Testing (Spanish) (T826)
2. Molecular Genetics: Biochemical Disorders Patient Information (T527)
3. If not ordering electronically, complete, print, and send a Biochemical Genetics Test Request (T798) with the specimen.
Useful For
Establishing a molecular diagnosis for patients with congenital disorders of glycosylation
Identifying variants within genes known to be associated with congenital disorders of glycosylation, allowing for predictive testing of at-risk family members
Genetics Test Information
This test utilizes next-generation sequencing to detect single nucleotide and copy number variants in 141 genes associated with congenital disorders of glycosylation: ALDOB, ALDOC, ALG1, ALG11, ALG12, ALG13, ALG14, ALG2, ALG3, ALG5, ALG6, ALG8, ALG9, ARCN1, ARV1, ATP6AP1, ATP6V0A2, B3GALNT2, B3GALT6, B3GAT3, B3GLCT, B4GALNT1, B4GALT1, B4GALT7, B4GAT1, C1GALT1C1, CCDC115, CHST14 ,CHST3, CHST6, CHST8, CHSY1, COG1,COG2, COG4, COG5, COG6, COG7, COG8, DDOST, DHDDS, DOLK, DPAGT1, DPM1, DPM2, DPM3, DSE, EOGT, EXT1, EXT2, FKRP, FKTN, FCSK, FUT8, G6PC3, GALE, GALK1, GALNT2, GALNT3, GALT, GET4, GFM1,GFPT1, GMPPA, GMPPB, GNE, GNPTAB, GOLIM4, GORASP2, CRPPA, LARGE1, LFNG, MAGT1, MAN1B1, MAN2B2, MBTPS1, MGAT1, MGAT2, MOGS, MPDU1, MPI, MPV17, NGLY1, NUS1, PAPSS2, PGAP2, PGAP3, PGM1, PGM2, PGM3, PIGA, PIGL, PIGM, PIGN, PIGO, PIGT, PIGV, PIGW, PMM1, PMM2, POFUT1, POGLUT1, POMGNT1, POMGNT2, POMK, POMT1, POMT2, PRKCSH, RFT1, RXYLT1, SEC23A, SEC23B, SEC63, SLC10A7, SLC26A2, SLC35A1, SLC35A2, SLC35A3, SLC35C1, SLC35D1, SLC37A4, SLC39A8, SRD5A3, SSR3, SSR4, ST3GAL3, ST3GAL5, STT3A, STT3B, STXBP1, SYP, TF, TMEM165, TMEM199, TRAPPC9, TRAPPC11, TRIP11, TSTA3, TUSC3, VMA21, and XYLT1. See Targeted Genes and Methodology Details for Congenital Disorders of Glycosylation Gene Panel  and Method Description for additional details.
Identification of a disease-causing variant may assist with diagnosis, prognosis, clinical management, familial screening, and genetic counseling for congenital disorders of glycosylation.
Testing Algorithm
For skin biopsy and cultured fibroblast specimens, fibroblast culture will be added at an additional charge. If viable cells are not obtained, the client will be notified.
For more information see:
-Lysosomal Disorders Diagnostic Algorithm, Part 2
-Congenital Disorders of Glycosylation: Screening Algorithm.
Method Name
Sequence Capture and Targeted Next-Generation Sequencing followed by Polymerase Chain Reaction (PCR) and Sanger Sequencing
Reporting Name
CDG Gene PanelSpecimen Type
VariesSpecimen Minimum Volume
Blood: 1 mL; Blood spots: 2 spots; Skin biopsy, cultured fibroblasts, or saliva: See Specimen Required
Specimen Stability Information
| Specimen Type | Temperature | Time | Special Container |
|---|---|---|---|
| Varies | Varies | ||
Clinical Information
Congenital disorders of glycosylation (CDG), formerly known as carbohydrate-deficient glycoprotein syndrome, are a group of disorders affecting several steps of the pathway involved in the glycosylation of proteins. CDG are classified into 5 groups. CDG types I and II will have abnormal biochemical findings detected by serum transferrin and serum total N-glycan analyses (see CDG / Carbohydrate Deficient Transferrin for Congenital Disorders of Glycosylation, Serum). In the other 3 groups these analyses will be normal.
CDG type I disorders are characterized by defects in the assembly or transfer of the dolichol-linked glycan, while CDG type II includes defects of the glycan moiety processing.
The third group includes disorders of glycosylphosphatidyl inositol anchor protein glycosylation. If clinically suspected, a flow cytometry analysis could facilitate the diagnostic workup.
The fourth group involves disorders of O-mannosylation, a process that takes place predominantly in the muscle and brain tissues.
The fifth group involves deglycosylation defects (eg, NAGLY1-CDG). The urine oligosaccharide profile by matrix-assisted laser desorption/ionization time-of-flight/time-of-flight mass spectrometer (MALDI-TOF/TOF-MS) may be abnormal and facilitate the diagnostic workup.
CDG typically present as multisystemic disorders with a broad range of clinical features including developmental delay, hypotonia, abnormal magnetic resonance imaging findings, skin manifestations, and coagulopathy. There is considerable variation in the severity of this group of diseases, ranging from hydrops fetalis to a mild presentation in adults. Almost all types of CDG are autosomal recessive in inheritance, but some are X-linked.
The broad clinical spectrum and genetic heterogeneity of CDG make a comprehensive panel a helpful tool in establishing a diagnosis for patients with suggestive clinical features.
Reference Values
An interpretive report will be provided.
Interpretation
All detected alterations are evaluated according to American College of Medical Genetics and Genomics recommendations.(1) Variants are classified based on known, predicted, or possible pathogenicity and reported with interpretive comments detailing their potential or known significance.
Clinical Reference
1. Richards S, Aziz N, Bale S, et al: Standards and guidelines for the interpretation of sequence variants: a joint consensus recommendation of the American College of Medical Genetics and Genomics and the Association for Molecular Pathology. Genet Med. 2015 May;17(5):405-424
2. Freeze HH, Chong JX, Bamshad MJ, Ng BG: Solving glycosylation disorders: fundamental approaches reveal complicated pathways. Am J Hum Genet. 2014;94(2):161-175
3. Krasnewich D: Human glycosylation disorders. Cancer Biomark. 2014 Jan;14(1):3-16
Test Classification
This test was developed and its performance characteristics determined by Mayo Clinic in a manner consistent with CLIA requirements. It has not been cleared or approved by the US Food and Drug Administration.CPT Code Information
81443
88233-Tissue culture, skin, solid tissue biopsy (if appropriate)
88240-Cryopreservation (if appropriate)
LOINC Code Information
| Test ID | Test Order Name | Order LOINC Value |
|---|---|---|
| CDGGP | CDG Gene Panel | 105346-1 |
| Result ID | Test Result Name | Result LOINC Value |
|---|---|---|
| 608524 | Test Description | 62364-5 |
| 608525 | Specimen | 31208-2 |
| 608526 | Source | 31208-2 |
| 608527 | Result Summary | 50397-9 |
| 608528 | Result | 82939-0 |
| 608529 | Interpretation | 69047-9 |
| 608530 | Resources | 99622-3 |
| 608531 | Additional Information | 48767-8 |
| 608532 | Method | 85069-3 |
| 608533 | Genes Analyzed | 48018-6 |
| 608534 | Disclaimer | 62364-5 |
| 608535 | Released By | 18771-6 |
Day(s) Performed
Varies
Report Available
28 to 42 daysReflex Tests
| Test ID | Reporting Name | Available Separately | Always Performed |
|---|---|---|---|
| CULFB | Fibroblast Culture for Genetic Test | Yes | No |