Carbohydrate-deficient transferrin (CDT) as a biochemical tool for the screening of congenital disorders of glycosylation (CDGs)

The aim of this study was to provide a tool based on CDT measurements for a diagnostic approach to identify patients affected by congenital disorders of glycosylation (CDG) in a selected population. Serum carbohydrate-deficient transferrin (CDT) of pediatric and adult patients (a total of 168 individuals) with neurological symptoms was analyzed. Abnormal results were confirmed by HPLC analysis and by enzymatic and molecular studies. We found 6 patients (3.8%) with abnormal serum CDT; only two of them (1.9%) showed increased amounts of disialo and asialo with HPLC analysis and were classified as CDG-Ia, the most frequent form of CDG, due to a deficiency of the phosphomannomutase enzyme. The CDT quantitative immunoturbidimetric procedure is a useful tool for CDG screening. HPLC analysis, however, permitted the correct identification of asialo and disialo transferrin concentrations.