The prevalence and association of inherited prothrombotic risk factors in children with established diagnoses of stroke, transient ischemic attack, or migraine were studied at Zagreb University School of Medicine, Croatia. Genotypic analyses were performed for factor V G1691A, factor II G2010A, MTHFR C677T, and 4 common platelet glycoprotein polymorphisms. Only factor V was significantly associated with increased risk for arterial ischemic stroke (AIS) in childhood and perinatal arterial ischemic stroke (PAS). Heterozygosity for factor V G1691A was associated with a 7-fold increased risk for AIS, PAS, and transient ischemic attack (TIA). Carriers of human platelet alloantigens had an increased risk of TIA. Human platelet alloantigen-2b allele was associated with a 2.23-fold increased risk for migraine, whereas factors V and II were not implicated. A trend toward an increased risk for migraine in children homozygous for MTHFR C677T, especially migraine with aura, was not statistically significant. 
COMMENT. Factor V G1691A is important in susceptibility to arterial ischemic stroke in childhood and the perinatal period, and transient ischemic attacks. Platelet glycoprotein polymorphisms may increase the risk of TIA and migraine.