Moreover, alloantibodies against HPA-3a account for approximately 3% of all NAIT cases.[13] HPA-3a antigen is located on the αIIb (GPIIb) subunit of αIIbb3 integrin (GPIIb-IIIa), which has a frequency of 85% in Caucasians. This evidence concerns the gene ITGA2B and fetal and neonatal alloimmune thrombocytopenia.