Transferrin Electrophoresis for diagnosis of CDGs (Also known as: Transferrin isoelectric focusing, TfIEF)

General Information

The congenital disorders of glycosylation (CDG) are a rapidly expanding group of metabolic syndromes with a wide spectrum of symptoms and severity. They all stem from deficient N-glycosylation of proteins. To date the group contains 18 different subtypes: 12 of Type I (disrupted synthesis of the lipid-linked oligosaccharide precursor) and 6 of Type II (malfunctioning trimming/processing of the protein-bound oligosaccharide). Main features of CDG involve psychomotor retardation; ataxia; seizures; retinopathy; liver fibrosis; coagulopathies; failure to thrive; dysmorphic features, including inverted nipples and subcutaneous fat pads; and strabismus. The transferrin electrophoresis test is used to detect changes in N-glycosylation, which can alter the isoelectric point of transferrin, giving rise to a different electrophoresis pattern. This test can not be used to rule out a diagnosis of CDG, as several of the sub-types will give a normal pattern. Further specialist testing is required to confirm a diagnosis.