P095 ABO blood group typing with the Oxford nanopore minion

Abstract

Aim Typing of ABO blood groups is a prerequisite for both recipient and donor when matching for a blood transfusion, solid organ, or stem cell transplantation. The ABO gene codes for a transferase, which will convert an H antigen into an A or B antigen. The combination of which ABO antigens are present determines an individual’s blood type. Typically, phenotyping of ABO is done using serological methods, but these methods are often unavailable in registry typing by buccal swabs, or samples of cord blood. The aim of this study is to use MinION to sequence the polymorphic region of the ABO locus, and perform ABO genotyping. Methods The ABO gene locus, located on chromosome 9, is expressed as 7 exons, with a total length of 18–20 kb. The blood group types A, B, and O show clear differences in the genetic sequence at the ABO locus, specifically in the polymorphic regions on exon 6 and 7. In this study, a 7 kb amplicon, which covers the distinguishing polymorphisms, was sequenced for 6 individuals with the 6 possible ABO genotypes (AA, BB, AO, BO, AB and OO). The reads were aligned against reference sequences from the dbRBC database, and important polymorphisms are categorized using in-house software. Results ABO alignments are visualized using Integrative Genome Viewer (IGV 2.3.90). DNA sequence data was sufficient to differentiate between the 6 possible ABO combinations based on 3 polymorphic positions. As few as 25 reads are sufficient for determining the ABO genotype of a sample, and higher coverage enables the construction of a consensus sequence for higher resolution genetic analysis. Conclusions MinION sequence data was adequate to differentiate between the 6 ABO combinations. Therefore, ABO sequencing on the MinION can be regarded as a novel platform for high throughput ABO genotyping, very suitable in cases where serology is unavailable. Furthermore, sequencing data will provide more insight into the diversity and extensiveness of polymorphism of the ABO genes.