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A HUMAN DISPERMIC CHIMAERA FIRST SUSPECTED FROM ANALYSIS OF THE BLOOD GROUP GENE‐SPECIFIED GLYCOSYLTRANSFERASES
Author(s) -
Watkins Winifred M.,
Yates A. D.,
Greenwell Pamela,
Bird G. W. G.,
Gibson M.,
Roy T. C. F.,
Wingham June,
Loeb W.
Publication year - 1981
Publication title -
international journal of immunogenetics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.41
H-Index - 47
eISSN - 1744-313X
pISSN - 1744-3121
DOI - 10.1111/j.1744-313x.1981.tb00749.x
Subject(s) - transferase , biology , glycosyltransferase , gene , microbiology and biotechnology , divalent , gene product , biochemistry , enzyme , chemistry , gene expression , organic chemistry
Summary The red cells of a normal male blood donor, K.S., were first grouped as B but he was found to lack anti‐A in his serum. Closer investigation revealed that his red cells had very weak A activity, demonstrable only by absorption and elution of anti‐A. He is a non‐secretor of ABH and a secretor of Le a . Blood group A‐, B and H ‐gene specified glycosyltransferases were detected in his serum. In contrast to the finding of a B antigen of normal strength on his red cells, the B transferase in his serum was only about 30% of the normal level and, despite the very weak A activity of K.S.'s red cells, the A transferase level was about 50% of that found in the serum of group A individuals with normal strength of A antigen. Moreover, the A transferase on the basis of its pH optimum, Km values for donor and acceptor substrates, activation by divalent cations, isoelectric focusing profile and capacity to convert O to A‐active cells, was characterized as the product of an A 1 gene. A family study showed that K.S.'s wife is group A 2 and that they have two sons, one group A 2 and the other group B. The group B son is assumed to have inherited a B gene from the propositus but the level of B transferase in the son's serum is three times as high as that in his father's serum. The wife of the propositus and his group A 2 son have normal A 2 transferases in keeping with their A 2 red cell status. The A 2 son therefore appears to have inherited an A 2 gene from his mother but neither the A 1 nor the B gene shown to be carried by his father. The distribution of transferase activities in K.S.'s red cells differs from that in his serum. A level of B transferase within the normal range was found in his red cell membranes but a very low level of A transferase was detected. The discrepancies between the serum transferases and ABO‐red cell group, together with the pattern of inheritance within the family, led to a suspicion of chimaerism. This was confirmed by the finding of fibroblasts with the female 46XX karyotype in cultures of the propositus' skin. These results suggest that K.S. is a dispermic chimaera with two different cell lines of the genotypes BO and A 1 O or A 1 A 1 . The group A 2 son is assumed to have inherited an O gene from his father. It seems probable that K.S.'s bone marrow and reproductive organs are comprised predominantly of the XY cell line which carries the blood group BO genotype whereas his skin and other tissues which contribute the A 1 transferase to his plasma, are partly made up of the XX cell line which carries the blood group A 1 O or A 1 A 1 genotype.