A Japanese propositus with D-- phenotype characterized by the deletion of both the RHCE gene and D1S80 locus situated in chromosome 1p and the existence of a new CE-D-CE hybrid gene

In a family study of a Japanese propositus with the D-- phenotype, the sero logical data of her D-phenotype and those of her parents were discrepant. G ene analysis of the propositus showed a gross deletion of the RI-ICE gene a nd a new rearrangement of RHCE to yield the CE-D-CE hybrid. It was demonstr ated that the hybrid CE-D-CE gene consisted of exon 1 from the RHCE gene, f ollowed by exons 3 to 7 from the RHD gene and exons 8 to 10 from the RHCE g ene. However, whether or not exon 2 of the RND or the RHCE gene was contain ed in the CE-D-CE gene remained unclear. Moreover, spacer analysis be tween both RN genes and the family study suggested that the D-- gene complex fro m the paternal and maternal sides consisted of only the CE-D-CE hybrid gene and a single RHD gene, respectively. For the purpose of confirming the par ent-child relationship, a paternity test using DNA fingerprint and polymera se chain reaction (PCR) analysis at the D1S80 locus were performed, DNA fin gerprints with two kinds of DNA minisatellite probes (33.15 and 33.6) confi rmed that the parent-child relationship in the D-propositus was compatible. However, in the present case, at the D1S80 locus, the PCR product derived from the mother was lacking, thereby negating a parent-child relationship, it is probable that the RH genes and D1S80 locus exist in close proximity, because they are situated in chromosomes Ip 34.3-36.1 and Ip 36.1-36.3, res pectively. These data suggested that at the stage of gametogenesis, both th e RHCE gone and the D1S80 locus from the maternal side may have been delete d, thereby producing the D-- gene complex.