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A novel isoform of platelet glycoprotein Ibα is prevalent in African Americans
Author(s) -
Aramaki Kaelen M.,
Reiner Alexander P.
Publication year - 1999
Publication title -
american journal of hematology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.456
H-Index - 105
eISSN - 1096-8652
pISSN - 0361-8609
DOI - 10.1002/(sici)1096-8652(199901)60:1<77::aid-ajh15>3.0.co;2-y
Subject(s) - haplotype , variable number tandem repeat , genetics , gene isoform , biology , tandem repeat , allele frequency , allele , genotype , population , platelet membrane glycoprotein , glycoprotein , gene , medicine , environmental health , genome
The heavy chain of platelet glycoprotein Ib (GPIb) contains two prevalent sequence polymorphisms. The first, Thr/Met 145 is responsible for the human platelet alloantigen system, human platelet antigen (HPA)‐2. The second is a tandem repeat polymorphism that consists of four variants, A, B, C, and D. Previous linkage studies in Caucasian and Eastern Asian populations have demonstrated that HPA‐2a (Thr 145 ) is associated with variants C and D, while HPA‐2b (Met 145 ) is associated with variants A and B. We have determined HPA‐2 and variable number of tandem repeats (VNTR) genotypes in three different North American ethnic groups. The gene frequency of HPA‐2b in the North American Indians was intermediate between African Americans and Caucasians, and similar to the frequency previously reported in Japanese. Furthermore, the VNTR‐A allele, which previously has been reported only in Eastern Asian populations, was present in two of 101 North American Indian individuals. These data are consistent with the hypothesis that the first Native Americans migrated to North America from Eastern Asia. Analysis of HPA‐2 and VNTR haplotypes demonstrated an unexpected linkage pattern in the African American population. A rare GPIbα isoform, HPA‐2b/VNTR‐C, was present in 2.2% of African American haplotypes. Furthermore, a novel GPIbα isoform, HPA‐2a/VNTR‐B, was present in 6.5% of African American haplotypes. These data suggest a more complex evolutionary pattern of GPIbα isoforms than previously proposed. Am. J. Hematol. 60:77–79, 1999. © 1999 Wiley‐Liss, Inc.