Distribution of six TF C (transferrin) subtypes in cord bloods and blood donors.

Isoelectric focusing was used to subtype the common TF C phenotype into C1, C2 and C3, increasing the proportion of heterozygotes from virtually zero to 0.31. Five of the six subtypes of TF C were found in a series of 200 blood donors and 200 cord bloods. The frequencies of the three alleles were: TFC1 = 0.80, TFC2 = 0.17 and TFC3 = 0.03 from cord bloods; and TFC1 = 0.84, TFC2 = 0.13 and TFC3 = 0.03 from blood donors. These frequencies were comparable with estimates from other Caucasian populations. The average probability of detecting non-paternity for this population is increased to 11% by subtyping C into C1 and C2, and further increased to 15% by subtyping C into C1, C2 and C3.