Pediatric antiphospholipid syndrome.

APS is rare in the pediatric age, but it represents an interesting phenomenon because most of the known "second hit" risk factors such as atherosclerosis, smoking, hypertension, contraceptive hormonal treatment, and pregnancy are not present in childhood. This could also be the reason for the prevalence of some clinical manifestations rather than others in PAPS. On the other hand, the increased frequency of infectious processes in the childhood age is likely responsible for the relatively high prevalence of non-pathogenic and transient aPL. Such points raise the problem of a different diagnosis or monitoring approach in pediatric APS. Of particular interest is the special entity of neonatal APS, which represents an in vivo model of acquired autoimmune disease, in which transplacentally acquired aPL cause thrombosis in the newborn. International registries for pediatric and neonatal APS are currently in place; epidemiologic, clinical, and laboratory re-search will help to shed light on all the still obscure aspects of this fascinating but rare disorder in the very young. Finally, treatment is less aggressive overall in pediatric APS, given the reluctance to anticoagulate children over the long term. Studies on the outcome of pediatric APS and the relative risks of prolonged anticoagulation in children are necessary to determine the type and duration of anticoagulation therapy.