Transferrin Isoelectric Focusing – CDG screening
| Test description | Congenital disorders of glycosylation, (CDG), also known as carbohydrate deficient glycoprotein syndromes, are a collection of disorders in which many glycoproteins are deficient or have reduced carbohydrate side chains. Many subtypes of congenital disorders of glycosylation have been described based on the isoelectric focusing patterns of transferrin and on clinical features. Sialic acid is the terminal sugar residue of the two carbohydrate side chains of transferrin. Any block in the synthesis of these side chains will result in an undersialylated transferrin molecule. Because it is a major serum protein and is easily detectable, transferrin is utilized as a marker in screening for congenital disorders of glycosylation. | |
| Disease name | Congenital Disorders of Glycosylation | |
| Indications | A congenital disorder of glycosylation should be considered for patients with failure to thrive, hypotonia, inverted nipples, unusual fat deposits, intellectual disabilities, psychomotor delays, stroke-like episodes, protein losing enteropathy, hypoglycemia, generalized dysmyelinization, optic atrophy. | |
| Methodology | Qualitative analysis of transferrin isoforms will be done by capillary electrophoresis | |
| Associated Tests | Mutation analysis for CDG Ia (PMM2), CDG Ib (MPI) and CDG Ic (ALG6) is available for identification of the causative mutation within a family, carrier status and prenatal diagnosis. | |
| Specimen Requirements | Transferrin analysis for carbohydrate deficient glycoprotein syndromes is performed on serum. Obtain 1 ml serum from a red top blood collection tube. | |
| Transport | Serum must be frozen and sent on dry ice. | |
| Turnaround time | 14 days | |
| CPT Codes | 82373 | |
| Cost | $150 | |
| Contact | For further information contact Kellie King, MS or Tim Wood, PhD at 1-800-473-9411 | |
Form Needed
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Kellie King, MS, CGC
Biochemical Lab
The Biochemical Lab provides diagnostic and screening tests for a variety of inherited metabolic disorders.