I-i- phenotype in a large kindred Indian family.

The I-i- phenotype was found to be a familial character up to three generations in a large Indian family having 93 members. 15 members showed highly depressed Ii antigens while 6 of the members had partial depression of the Ii antigens on their red cells. It was evident in the family that the phenotype is associated with A1 antigen. The A1 antigen score on the red cells was significantly higher among the subjects with depressed Ii antigens. The I-i- status was not considered as a dominant or a recessive character nor does the partial depression of the Ii antigens indicate a heterozygous state of the variant gene.