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BACKGROUND AND OBJECTIVES: ) has been linked to genetically different blood cell populations such as in chimerism, or to rare variants in either ABO exon 7 or regulatory regions. Clarification of such cases is challenging and would greatly benefit from sequencing technologies that allow resolving full-gene haplotypes at high resolution. MATERIALS AND METHODS: B phenotype. Confirmation analyses were carried out by Sanger sequencing and included samples from other family members. RESULTS: Our data revealed a novel heterozygous g.10924C>A variant on the ABO*A allele located in the transcription factor binding site for RUNX1 in intron 1 (+5.8 kb site). Inheritance was shown by the results of the donor's mother, who shared the novel variant and the anti-A specific mixed-field agglutination. CONCLUSION: phenotypes. Overall, long-range PCR combined with nanopore sequencing proved powerful and showed great potential as an emerging strategy for resolving cases with cryptic ABO phenotypes.
Thun et al. (Tue,) studied this question.