Dombrock genotyping in Brazilian blood donors reveals different regional frequencies of the HY allele

Abstract

BackgroundDombrock blood group system genotyping has revealed various rearrangements of the Dombrock gene and identified new variant alleles in Brazil (i.e., DO*A-SH, DO*A-WL and DO*B-WL). Because of the high heterogeneity of the Brazilian population, interregional differences are expected during the investigation of Dombrock genotypes. ObjectiveThe present study aims to determine the frequencies of Dombrock genotypes in blood donors from Minas Gerais and compare the frequencies of the HY and JO alleles to those of another population in Brazil. MethodsThe frequencies of the DO alleles in Minas Gerais, a southeastern state of Brazil, were determined from the genotyping of 270 blood donors. Genotyping involved polymerase chain reaction and restriction fragment length polymorphism analysis to identify the 323G>T, 350C>T, 793A>G, and 898C>G mutations, which are related to the HY, JO, DO*A/DO*B, and DO*A-WL/DO*B-WL alleles, respectively. Moreover, the frequencies of rare HY and JO alleles were statistically compared using the chi-square test with data from another Brazilian region. ResultsThe HY allele frequency in Minas Gerais (2.4%) was almost twice that of the JO allele (1.5%). The frequency of the HY allele was significantly higher (p-value = 0.001) than that in another Brazilian population and includes a rare homozygous donor with the Hy- phenotype. In addition, the DO*A-WL and DO*B-WL alleles, which were first identified in Brazil, were found in the state of Minas Gerais. ConclusionsThe data confirm that the frequencies of DO alleles differ between regions in Brazil. The population of Minas Gerais could be targeted in a screening strategy to identify the Hy- phenotype in order to develop a rare blood bank.

Sequencing of the ART4 gene in sub‐Saharan cohorts reveals ethnic differences and two new DO alleles: DO*B‐Ile5Thr and DO*B‐Trp266Arg

“…Castilho and colleagues showed that DO*HY was five times more common than DO*JO in black donors in New York while DO*JO was more than twice as common as DO*HY in Brazilian blacks, suggesting that Afro‐Brazilians and Afro‐Americans came from different places in Africa. Another study showed that the frequency of DO*HY allele in state of Minas Gerais in southeastern Brazil was almost twice that of the DO*JO allele, suggesting that donors in Minas Gerais are more similar to Afro‐American donors in New York than other Brazilian blacks. Our data prove that of DO*JO and DO*HY variant alleles frequencies are higher in sub‐Saharans than Afro‐Americans or Afro‐Brazilians.…”

“…Nevertheless, except a few reports describing genotyping of the four main Dombrock antigens, the scope of antigen frequency studies has been limited and other variant alleles have not been studied . ‐ The purpose of this report was to describe genetic diversity based on sequencing of ART4 gene in various African cohorts and to compare the frequencies obtained in nonpygmoid and pygmoid ethnic groups with each other.…”

Blood group polymorphisms in Brazil

“…In a multi-ethnic population, such as that of Brazil, the frequencies of the different blood group antigens vary significantly. Genotyping studies in this population have shown that the blood group polymorphisms differ significantly from other populations6, 7 and studies inside the country have also shown a heterogeneous distribution of blood group alleles and variants between groups of people from different regions 8, 9. Moreover, the high degree of genetic mixture in the Brazilian population facilitates the generation of new alleles 10, 11.…”

The screening of rare blood donors in a highly admixed population: A new approach for Holley and Diego genotyping and impact of genomic and self‐reported ancestry

“…Individual samples obtained from Brazilian blood donors previously genotyped by PCR‐restriction fragment length polymorphisms (PCR‐RFLP) for Diego and Dombrock polymorphisms were used to standardise DI*A/DI*B (rs2285644) and DO*HY (rs28362797) genotyping by real‐time PCR.…”