Hemolytic disease of the newborn caused by anti-Rh32 and demonstration that RN encodes rhi (Ce,Rh7).

A family is described in which the mother made anti-Rh32 as a result of pregnancy; her second liveborn child had hemolytic disease of the newborn and required an exchange transfusion. In investigating the family, it was found that the father's RN gene did not make rhi and that his second Rh gene made normal amounts of c and e but a reduced amount of f. In the two children of the couple, who inherited a normal r or Ro from their mother, the paternally derived RN encoded an amount of rhi that could be detected in direct typing tests. In the father, lack of production of rhi by RN may have represented a suppressive effect of the ce(f) gene in trans to RN or the presence of an unlinked suppressor of Rh that might also have been responsible for the reduced production of f by his r or Ro gene. The two children in this family are the first persons in whom RN has been shown to make rhi.