[The family investigation of a weak D type 15 donor]

To study the genetic feature of weak D type 15 allele (RHD845A) in a Chinese family.

Rh D, C, c, E and e phenotypes of 4 members in a weak D type 15 family were tested by serological and polymerase chain reaction (PCR), D antigen was proven by indirect antiglobulin test. A pair of primers specific for RHD845A were designed, and a sequence specific primer-PCR (PCR-SSP) method was established to detect RHD845A allele in all family members. Subsequently the dual-tube PCR method was used to determine the RHD zygosity of 4 members.

The RHD845A allele existed in all 4 family members and the RHD zygosity test showed that all members were RHD +/RHD + homozygous. The parents and nephew possessed one normal RHD gene as RHD845A allele carriers, which caused RhD positive. The proband and his old-sister took two RHD845A alleles, which caused weak D phenotype.

The proband is the weak D type 15 allele homozygous. The weak D type 15 gene is an ancestral allele, but not a mutation.