[Maternal-fetal chikungunya infection associated with Bernard-Soulier syndrome]

Neonatal thrombocytopenia may stem from several origins. A newborn was hospitalized on the 3rd day of life with thrombocytopenia likely due to maternofetal autoimmune thrombocytopenia. Two days later, he displayed a chikungunya virus infection, during a severe epidemic on Reunion Island. The characterization of human platelet antigen (HPA) in the parents showed incompatibility in the HPA-3 system; however, no detectable antiHPA-3a antibody was found in the mother's serum. The persistence of moderate thrombocytopenia led to the diagnosis, using flow cytometry, of Bernard-Soulier syndrome (BSS), with no detectable GPIbIX. This case shows that neonatal inherited thrombocytopenia may be difficult to characterize, especially when it is associated with an acquired cause.