HPA-1a incompatibility

The most common cause of FNAITFetal and neonatal alloimmune thrombocytopenia A rare condition in which a mother’s immune system attacks fetal platelets, leading to dangerously low platelet levels before and/or after birth., this occurs when there is a genetic mismatch between a pregnant mother, who is HPAHuman platelet antigen Proteins found on the surface of platelets. Incompatibility between maternal and fetal human platelet antigens can trigger FNAIT.-1a negative, and her baby, who has inherited the HPA-1a positive antigen from the father.