Tissue Typing Lab Director Brigham and Women's Hosptial; Harvard Medical School, Massachusetts, United States
Background/Case Studies: Accurate typing of blood group antigens is essential for safe and efficient transfusion. It has been shown that high density DNA arrays have a >99% concordance with previous typing in samples from individuals of European ancestry. In this study, we present the results of high density DNA genotyping on donors of African ancestry.
Study
Design/Methods: High density DNA array based genotyping was performed on 1,925 samples of African ancestry according to previously published methods. Briefly, Axiom arrays were run on a GeneTitan, followed by the Axiom software analysis suite and blood group calling using bloodTyper software with comparison to previous testing results. All work was done with the approval of the institutional ethics committee.
Results/Findings: The overall genotyping concordance rate was 99.7% (Table 1). In addition, detailed analysis was performed for changes prevalent in those of African ancestry: Duffy null/weak, U−, DIIIa-CEVS(4-7)-D hybrid, and HbS & HbC. There were 243 samples with known Duffy null and Duffy weak phenotypes with 100% concordance for 46 Fy(a−b+), 29 Fy(a+b−), 16 Fy(a+b+), 4 Fy(a−b+w), 2 Fy(a+b+w); with one discordance (99.3% concordance) among the 146 Fy(a−b−). There were 245 samples with previous U genotyping with 100% concordance for the 1 U+var, 5 U−, and 239 U+. There were 72 samples with previous DIIIa-CEVS(4-7)-D results with a 100% concordance for the 2 homozygous and 11 homozygous; with 3 discorances (95% concordance) for the 59 heterozygotes. There were 1,925 samples with previous HbA and HbS testing with 100% concordance for 1842 HbA/A, 78 HbS/A, 2 HbS/S. In addition, the array found 3 HbC/C individuals which were later confirmed to be concordant with other testing methods. Conclusions: Here we report a large-scale evaluation of high density DNA array genotyping in individuals of African ancestry, which showed a high concordance with previous testing. As such high density DNA arrays represent a promising technology for blood group genotyping. Future work will focus on samples of Asian ancestry.
Importance of research: Here we report a large-scale evaluation of high density DNA array genotyping in individuals of African ancestry, which showed a high concordance with previous testing. As such high density DNA arrays represent a promising technology for blood group genotyping.
