Low prevalence of a polymorphism of platelet membrane glycoprotein Ib betaassociated with neonatal alloimmune thrombocytopenic purpura in Asian populations

Iy alloantigen system is the first polymorphism of platelet glycoprotein Ib beta reported to cause neonatal alloimmune thrombocytopenic purpura. We in vestigated the allelic frequency of Iy alloantigen among Japanese and Korea n populations by polymerase chain reaction-restriction fragment length meth od to determine the possibility of alloimmunization against Ip Two hundred and nine Japanese and 97 Korean subjects were examined. All 306 individuals were homozygous for glycine at amino acid position 15 and negative for Iy. The allelic frequency of Iy in these populations was calculated to be less than 0.0016. Alloimmunization associated with Iy antigen in Asian populati ons seems unlikely from these results. (C) 1999 The Japanese Society of Hem atology.