Frequencies of platelet‐specific alloantigen systems 1–5 in three distinct ethnic groups in Brazil

Abstract

The human platelet antigen (HPA) systems are related to immune platelet disorders as well as to the development of occlusive vascular disease. Several distinct biallelic HPA systems are known, and a heterogeneous distribution of HPA alleles has been described among distinct ethnic groups. In this study we genotyped 320 carefully selected individuals from three distinct ethnic groups in Brazil (Caucasians, Blacks and Amazonian Indians) for the HPA-1, -2, -3, -4 and -5 systems. A similar prevalence for all HPA alleles was found in Brazilians of Caucasian and Black descent. These data contrast with those reported for similar ethnic groups in other countries. Among the Amazonian Indians, no b allele of the HPA-1, -4 and -5 systems was identified. The data presented here could be useful in the diagnosis of alloimmune platelet disease, in genetic counselling and in the development of screening programmes for HPA-related diseases.

Genetic variability of platelet glycoprotein Ibα gene

“…However, the prevalence of VNTR alleles differs between Indigenous and the Oriental populations. Notably is the absence of the largest VNTR, the A allele, which is present in 8-15% of Oriental population [7,24,32]. The distinct prevalence of these alleles among Indigenous population in this study may be influenced by genetic drift or regionspecific selection pressure and importantly, by the high rate of consanguineous marriage [40].…”

“…The characterization of the HPA-2 alleles was performed as reported by Castro et al [32]. Following digestion of the PCR products with BsaHI in the presence of HPA-2a, three fragments of 61, 116, and 242 bp were obtained, whereas in the presence of HPA-2b allele, only two fragments (61 and 358 bp) were observed.…”

“…In a previous study, we reported the prevalence of HPA-1 to HPA-5 alleles in these ethnic groups [32]. Here we analyzed the genetic linkage of the HPA-2, VNTR, and Kozak polymorphisms of the GPIba gene among subjects from all three ethnic groups (Table III).…”

Human Platelet Antigens in Brazilian Multiethnic Populations: Occurrence of Regional Variation and Frequency in a Large Urban Center (Belo Horizonte)

“…The Brazilian population is highly heterogeneous and admixed, presenting important differences in genomic ancestry among regions [9,31]. Studies carried out in Brazilian populations have demonstrated the existence of significant differences in the distribution of HPA antigens throughout the Brazilian territory [10,25], which could generate regional differences in the risk of HPA alloimmunization and its consequences. In the present study, we investigated the variation of HPA frequencies in different Brazilian populations, compared with other world populations.…”

“…Studies on HPA frequencies in Brazil have proposed the occurrence of heterogeneity across the Brazilian population produced by the different degrees of admixture throughout the country, suggesting the importance of the formation of HPA panels composed of regional blood donors [10,11]. …”