Glycosylation of transferrin in Alzheimer's disease and alcohol-induced dementia.

Transferrin is a glycosylated metal-binding serum protein. Carbohydrate-deficient transferrin (CDT) is a marker of recent and heavy alcohol intake. A genetic variant of transferrin, TfC2, occurs with increased frequency in patients with Alzheimer's disease (AD). Hence the question arose whether, in addition to an altered amino acid sequence, there could also be a difference in the glycosylation state of transferrin in patients with dementia. Serum samples of 37 AD and 13 Alcohol-induced dementia patients as well as 10 healthy controls were analyzed for abnormal Tf variants, using isoelectric focusing followed by blotting with anti-Tf antibodies. This allowed the direct visualization of glycosylation variants of transferrin, and assessment of any increase in underglycosylated forms (di-, mono- and asialo transferrin).