2016 Volume 62 Issue 5 Pages 601-605
The Bm and ABm phenotypes are the most prevalent ABO subgroups in Japanese and are produced via the partial deletion of intron 1 of the B gene. The deleted section is 5.8-kb long and includes a transcription enhancer element, which contains 2 GATA motifs. A case in which an individual who exhibited the Bm phenotype displayed a GATA>GAGA mutation, but not the abovementioned deletion in the transcription enhancer element, has been reported. The individual's serological properties were similar to those of the typical Bm phenotype, but B antigen could not be detected in their saliva because they were a non-secretor.
Here, we report a novel case in which a secretor who exhibited the Bm phenotype was found to be carrying a GATA>GAGA mutation in the B gene. This mutation reduced the expression of B antigen on red blood cells, but did not affect the amount of B antigen in the subject's saliva.
