The Inheritance of the Rh Blood Groups

Dosage studies of 114 Down's syndrome and 7 other autosomal trisomics failed to show any lengthening of reaction times of the Rh antigens or of S, Fya, Jka or Jkb, nor was there any alteration in reaction times for Xga in 13 Turner's and 7 Klinefelter's. Distribution of length of reaction times was tabulated for the Rh antigens c, E and e in 200 families and the C and D antigens in individual families. The reaction times of at least 2 members of 5 families fell outside the expected range. Two of the deviations were explicable on the basis of known causes (‐D‐ and depression of D by r′). The reasons for a second deviation in one of these 2 families and of a deviation in 2 others is uncertain. In the fifth family the cause was an unlinked Rh depressor gene.