Figure 5. Categorization of pregnancy types according to the relative number of C2 genes or by parental origin of the fetal C2.

(A) Pregnancies were separated into 3 groups: those in which the fetus had fewer C2 genes than the mother (i.e., B and E), those in which the fetus and mother had the same number of C2 genes (i.e., A, D, and G), and those in which the fetus had more C2 genes than the mother (i.e., C and F). (B) Alternatively, pregnancies were selected in which the origin of the single fetal C2 gene could be definitively identified as being derived from either the father (i.e., C and D1) or the mother (i.e., D2 and E). HLA-C allele typing to 4 places was used to identify the parental origin of the fetal C2, distinguishing D1 from D2. See Table 3 for comparison of the groups.