Interpretation: the molecular presence of guanine and adenine at the polymorphic site that is indicative of the kidd (jk) antigen represents a heterozygous jk(a+b+) individual 1, as was reported by hea beadchips (b)(4)_7 and (b)(4)_7.However, the individual is also homozygous for a polymorphism at c.588a>g in exon 6 (rs2298718) that could weaken the expression of the jka and jkb antigens2,3,4.Using sequence-specific primer pcr and bi-directional sanger sequencing analysis, this individual is c.28g in exon 3, c.226g and c.303g in exon 4, and c.588a in exon 6 demonstrating lack of the jk*01n.20 [jk(a-b-)] variant5.This is a case where a sample contains a molecular event that affect the blood-group antigen expression, and the nucleotide changes associated with this event are not explicitly monitored by the hea assay as described in the package insert (part number 190-20210).(b)(4).
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