Lack of influence of TfC genetic phenotype on iron, iron-binding capacity, percentage saturation, and immunologically determined transferrin in blood donor sera.

Although over 22 different genetic variants of human transferrin have been described, three subtypes of the TfC allele, TfC1, TfC2, and TfC3, have a combined gene frequency of over 0.95 in most US populations. We measured iron, iron-binding capacity, and immunologically determined transferrin in blood donor sera of known TfC phenotypes, since we thought the results might be transferrin phenotype dependent, as is haptoglobin concentration on haptoglobin genetic phenotype. However, we found no major differences in the mean iron, mean iron-binding capacity, mean percentage saturation, or mean immunological transferrin in blood donors of different TfC phenotypes. We also found reasonably good correlation (r = 0.86) between immunologically determined transferrin and chemically determined iron-binding capacity with no significant differences in the linear regression parameters for sera of various TfC phenotypes.