The more recent “weak D type” terminology. is based only on structural features, including the D antigen and the nucleotide sequence of the RHD gene, unavailable in 1984. This finally resolved in 1999 the somewhat circular definition of partial D from 1984 and allowed to separate by more rigorous scientific criteria “true” weak D types from partial D at the time of their first observation. An anti-D immunization event or lack thereof has never been part of the weak D type terminology, as it is not a mandatory feature of the partial D terminology used today.