Abstract
Few studies of activated protein C resistance (APCR) and thromboembolism in childhood
have been published. In the majority of childhood thromboses reported, the factor
V Leiden mutation was associated with venous thromboses; however, one case report
and three studies described arterial thromboembolism in infants and children due to
the common mutation in the factor V gene. In one neonate purpura fulminans occurred,
and heparininduced thrombocytopenia type II was additionally documented. Two case
reports and seven of nine studies reported associated clinical conditions together
with inherited coagulation disorders. In three studies homozygous patients were mentioned.
There are few studies describing the interaction between APCR and coagulation or the
fibrinolytic system in symptomatic and nonsymptomatic infants. Compared with healthy
brothers or sisters and a healthy age-matched control group, thrombin generation,
D-dimer, PAI-1 activity, and t-PA antigen were found clearly elevated in children
with APCR. In addition, infants and children with the Arg506-to-Gln mutation in the factor V gene showed significantly increased thrombomodulin
concentrations along with normal protein C activities compared with relatives and
healthy controls. No difference was recorded in these studies between heterozygous
infants and children without vascular occlusion and patients who previously had suffered
from thromboembolism.
Until long-term data are available for the treatment of patients with APCR, such children
should be treated in the same way as patients with deficiencies of protein C, protein
S, or antithrombin.
Keywords:
APC resistance - thrombin generation - thrombomodulin - D-dimer - PAI-1 activity
