Molecular bases of partial D phenotypes.

The different alleles of RHD that cause partial D phenotypes are depicted here graphically. The genetic structure of each partial DRHD 10-exon gene is shown, as are associated low-incidence antigen(s) and the estimated gene frequency. RHD (ie, wild type) exons are shown as black boxes; where they have been replaced byRHCE equivalents is shown as white boxes. Missense mutations are indicated within the exon where they occur. We have used the original Roman numeral notation (ie, D^II to D^VII) and the more recent 3-letter notation (eg, DFR, DBT) for the different D categories. Where partial D phenotypes have identical (or very similar) serologic profiles but different genetic backgrounds, we have adapted the classification originally described by Mouro et al190 to describe different D^VIphenotypes (types I and II). Thus, we depict D^IV types I to IV, D^V types I to VI; D^VI types I to III, and DFR types I and II. We use D^Va to indicate the presence of the D^W antigen and D^V to represent samples that have a similar molecular background but that either do not express the D^W antigen or have not been tested for this antigen.Few = 1 to 10 examples. Many = 11 or more examples as indicated by serological testing. D^VII is common (1 in 900) in the German population.191 Under “Ethnic Origin,” B = black, C = Caucasian, and J = Japanese. The information used for the point mutations used in this figure are as follows: D+G−106; DNU and D^II192; D^HMi92; D^VII193; D^Va71,194 DFW195; DHR.196 The information used for the rearrangements in this figure was obtained from the following: D^IIIa197; D^IIIb106; D^{IIIc 198}; D^IVa type I 194; D^IVbtype II194; D^IVb type III92; D^IVb type IV195; D^Va type I194; D^Va type II194; D^V type III102; D^Va type IV156; D^V type V156; D^Vtype VI156; D^VI type I199,200; D^VI type II190; D^VI type III71; DFR type I194; DFR type II201; DBT type I202; DBT type II203; ARRO-1204; DCS205.