New RHD variants
Different polymorphisms of RHD have been found including alleles with deletion of certain D-exons and insertion of the corresponding RHCE counterparts and missense mutations leading to exchanged amino acids either in the the six loops of the extracellular D-domains or the intracellular/ transmembrane domains of the D-antigen. According to German guidelines, D-weak phenotypes are considered to be D-positive and should be transfused with Rhesus-D positive blood products. Except for D-weak types 4.2, 15 and 26 where immunization of recipients could be shown, other D-weak phenotypes were so far not found to induce development of allo-antibodies.