Lack of influence of Tf^C 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 Tf^C allele, Tf^C1, Tf^C2, and Tf^C3, 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 Tf^C 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 Tf^C 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 Tf^C phenotypes.