Transferrin C subtypes in extremely premature newborn infants.

Genetic typing of serum transferrin was performed in a group of 88 extremely premature infants (gestation age less than 32 wk) and in a control group of 351 full-term infants, using isoelectric focusing technique on ultrathin layer of polyacrilamide gel. A major incidence of C2 type was found among the preterm infants when compared to full-term infants X2 = 22,86, (P less than 0.001). In view of the previously reported higher incidence of this phenotype in women prone to spontaneous abortion, a selective mechanism associated with this serum transferrin type promoting spontaneous abortion and preterm delivery, seems to occur. The relative risk of preterm delivery were calculated to 1.4 and 8.3 for the C2-1 and C2 types, respectively. Supportive evidence in favour of this hypothesis is offered by the correlation existing between transferrin C2 allele and placental alkaline phosphatase variant F, the latter being associated with increased risk of spontaneous abortion.