Mosaic Type (partial D)

The D antigen is a mosaic consisting of several parts, e.g., D^ABCD. Most people who are D-positive inherit a gene which produces all parts of the D mosaic. Weak D people inherit a gene which produces only part of the mosaic, e.g., D^AB , or D^BC , etc. Because this gene can be transmitted directly to offspring, it can be considered to be hereditary. Typically, people are identified as having the mosaic type or partial D phenotype when they make anti-D as an alloantibody. (Patricia Tippett has described mosaic D categories II through VII; the outdated D^ABCD model is used here as a simpler model to explain the concept.)

Mosaic Type (partial D)