Defects in the biosynthesis of N-linked human protein glycosylation leads to a group of multisystem disorders collectively called congenital disorders of glycosylation (CDG). CDG present in infancy with neurologic symptoms that include psychomotor retardation, ataxia, hypotonia and stroke-like episodes. Many haemostatic system proteins only present biological activity after glycosylation. The aim of this study was to evaluate coagulation inhibitors (free protein S, protein C and antithrombin) and coagulation factors (VIII, IX and XI) in CDG type I patients. Eleven patients with CDG type I (three males and eight females) with a mean age of 5.6 years old, and eight patients without CDG (four males and four females) with a mean age of 4.5 years old (control group) were evaluated. The diagnoses of CDG type I were confirmed by isoelectric focusing of serum transferrin. When coagulation inhibitors were evaluated, decreased activity of free protein S and protein C, and a pronounced reduction of antithrombin were observed compared to the control group. There was no significant difference for coagulation factors VIII and IX but a markedly decrease in factor XI. The present results suggest that a combined deficiency of coagulation inhibitors is responsible for the pro-thrombotic state observed in CDG patients. We recommend that a haemostatic analysis should be performed in CDG patients with clinical haemostatic manifestations before invasive procedures are performed.
Glycosylation; thrombophilia; blood coagulation factors
