Microheterogeneity of some serum glycoproteins in neurodegenerative diseases

Participation of protein polymorphism is often considered in the pathogenesis of various diseases. Aberrant protein glycosylation has been recognized to play major roles in human disorders, including neurodegenerative diseases.

The aim of the study was to examine possible involvement of protein genetic variants and degree of glycosylation of some serum glycoproteins in the manifestation of neurodegenerative disorders in a Czech population sample.

Apolipoprotein (Apo) E and three main serum markers of glycosylation defects (transferrin, Tf, alpha1-antitrypsin, aAT and ApoCIII) in patients with Alzheimer's dementia (AD), Parkinson's disease (PD) and vascular dementia (n=62, 139 and 44, respectively) were analyzed by isoelectric focusing. Children with serious neurological symptoms (n=55) and three age-matched control groups (n=45, 45 and 42) were examined for comparison.

Of the supposedly pathognomonic protein variants Tf C2, aAT ZM and ApoE e4 only the latter was detected with higher frequency in AD patients; significant synergy of the C2/e4 allelic combination was not confirmed. The most prominent finding among PD adults was an increased appearance of Tf C2 allele and significant mean hypoglycosylation of ApoCIII, besides a C2/e4 positive correlation in PD seniors. Laboratory signs of Tf hypoglycosylation and a pattern of Tf/ApoCIII hyperglycosylation have been occasionally found.