In paediatric TE-PE, the prevalence of central venous catheters was 23 %, immobilisation 38 %, systemic infection 31 % and obesity 13 %, elevated Factor VIII or von Willebrand factor levels 27 %, Protein C deficiency 17 %, Factor V Leiden 14 % and Protein S deficiency 7 %.
In addition to factor V G1691A and PT G20210A mutations, other prothrombotic risk factors including protein C and protein S deficiencies and elevated factor VIII levels were commonly associated with pediatric nonstroke arterial thrombosis cases in the present study.
The frequency of antithrombin deficiency (12% vs 0%), increased activated protein C (APC) resistance (32% vs 6%), total protein S deficiency (11% vs 1%) and elevated factor VIII:C activity (43% vs 17%) was significantly higher in female cases compared with controls.
Beside the frequent polymorphism already described on Pro 626, we detected 18 different sequence variations by studying exons II, IV, V, VIII, X, and XV in 19 of 100 consecutive patients with protein S deficiency.
A missense mutation (Asn 217 to Ser), which may interfere with calcium binding, was also detected in exon VIII in a patient with type III protein S deficiency.