CDT Congenital Glycosylation
Label Mnemonic: CDG
Epic Lab Code: LAB7371
Downtime Form: A-1a Miscellaneous Request
Commercial Mail-out Laboratory
5231 RCP
356-8593
Specimen(s):
Serum
Specimen Instructions:
Please provide a reason for referral with each specimen.

Draw blood in a plain, red-top tube.

Note: This test is for congenital disorders of glycosylation.

Patient's age is required on request form for processing.
Collection Medium:
Red top tube 5 mL (Clot Activator)
Minimum:
0.1 mL of serum
Delivery Instructions:
Submit specimen to laboratory as soon as possible after collection.
Turn Around Time:
5 days upon receipt at reference laboratory
Reference Range:
Ratio Normal Indeterminate Abnormal Transferrin Mono-oligo/Di- < or =0.06 0.07-0.09 > or =0.10 oligo Ratio Transferrin A-oligo/Di- < or =0.011 0.012-0.021 > or =0.022 oligo Ratio Transferrin Tri-sialo/Di- < or =0.05 0.06-0.12 > or =0.13 oligo Ratio Apo CIII-1/Apo CIII-2 Ratio < or =2.91 2.92-3.68 > or =3.69 Apo CIII-0/Apo CIII-2 Ratio < or =0.48 0.49-0.68 > or =0.69
Interpretive Data:
Positive test results could be due to a genetic or nongenetic condition; additional confirmatory testing is required. Results are reported as the mono-oligosaccharide/di-oligosaccharide transferrin ratio, the a-oligosaccharide/di-oligosaccharide transferrin ratio, the tri-sialo/di-oligosaccharide transferrin ratio, and the apolipoprotein CIII-1/apolipoprotein CIII-2 ratio, and the apolipoprotein CIII-0/apolipoprotein CIII-2 ratio. The report will include the quantitative results and an interpretation. The congenital disorders of glycosylation (CDG) profiles are categorized in 4 types. When the profile cannot be categorized following the above classification, all the abnormal transferrin and/or Apo-CIII species will be reported descriptively according to the molecular mass stating the possible structures.
Comments:
Congenital disorders of glycosylation (CDG), formerly known as carbohydrate-deficient glycoprotein syndrome, are a group of more than 45 inherited metabolic disorders affecting several steps of the pathway involved in the glycosylation of proteins. CDG are classified into 2 groups. Type I CDG is characterized by defects in the assembly or transfer of the dolichol-linked glycan, while type II involves processing defects of the glycan. Apolipoprotein CIII (Apo-CIII) isoforms, a protein with a single core 1 mucin type O-glycosylate protein, is a complementary evaluation for the CDG type II profile. This analysis will evaluate mucin type O-glycosylation, a defect that happens in the Golgi apparatus, and will change the ratios, increasing the asialo or monoisalo forms and decreasing the fully sialilate (disialo) forms. In young children (>1 month) and in liver disease, the Apo-CIII2 may be increased. Children younger than 6 months, and clinically suspected of having ATP6V0A2-CDG, may have normal transferrin profile with abnormal Apo-CIII profile.

Useful For
Screening for congenital disorders of glycosylation.
Methodology:
Affinity Chromatography/Mass Spectrometry (MS)
CPT Code:
82373