A transferrin variant in a kindred with cystic fibrosis.

An electrophoretically fast transferrin (Tf) variant, TfB, was found in a cystic fibrosis homozygote. Since neither cystic fibrosis nor the transferrin structural gene has been mapped on human chromosomes, a study was made of this kindred. Genetic markers including ABO, MN, Rh, Fy blood groups and Tf, group-specific component, and haptoglobin serum protein polymorphisms were determined in available members of the kindred. The genes for cystic fibrosis and Tf appear to segregate independently in the kindred, although crossing-over between linked genes in the homozygous cystic fibrosis brother of the propositus could account for the genotypes observed.