[Some aspects of the allelic interaction in family studies of normal A1B and A2B subjects (author's transl)].

The authors have selected three series of families presenting several heterozygous AB gene combinations: the same gene A and the same gene B; the same gene B and different genes A; and the same gene A and different genes B. The results concerning these families show that the quantitiy of A1 and A substances (for A1B) or A (for A2B) is related to the "quality" of the alpha-D-galactosyl transferase acting on a more or less important H substratum. The alpha-N-acetyl-D-galactosaminyl transferase seems to have a minor function.