Immunogenetic studies of the platelet-specific antigen P1A1 (Zw(a))

The phenotype frequency of the platelet-specific antigens P1A1/A2 ( = Zw(a,b)) in the German population (N = 711) is 97.75% and 2.25% respectively. The corresponding gene frequencies are P1A1 0.85; P1A2 0.15. The P1A1 determinant is codominantly inherited (19 families; 151 family members). There is a strong gene dosage effect between P1A1 homo and heterozygous individuals. No definite linkage of the locus P1A1 versus the loci HLA-ABC, ABO, or Rh was found.