Blood Group Chimerism as a Clue to Generalized Tissue Mosaicism

Abstract

Blood group studies disclosed mosaicism of the red cells in a healthy male Negro donor who was subsequently also found to have mosaicism of skin and bone marrow with respect to XX‐XY chromosomal constitution and whose skin showed unequal pigmentation. The two red cell populations were unequal in numbers with a ratio of approximately 10:1. The major population was group A, Jk a negative and showed the sickling trait in wet films and by electrophoresis. The minor population was group B, Jk a positive, did not sickle and contained only hemoglobin A. Both red cells were Le a positive despite the fact that the propositus was a secretor. However, only A substance was secreted and it was demonstrated by salivary studies and with the help of complete family studies, that the minor genetic product which had produced the group B erythrocytes represented the gene contribution se se and was the source of Le a substance sufficient to coat both red cell populations. The family studies showed that the propositus had received a 2 allele contribution from each parent and was therefore the result of double fertilization of a double egg nucleus presumably an ovum and a polar body.