RESUMO
OBJECTIVE: Recently our group has found that the correlation between birth weight and placental weight - an index of a balanced feto-placental unit development - is influenced by genetic factors. Since adenylate kinase locus 1 (AK1) is a polymorphic enzyme that plays an important role in the synthesis of nucleotides required for many metabolic functions, we have investigated the possible role of its genetic variability in the correlation between birth weight and placental weight. STUDY DESIGN: 342 consecutive healthy newborn infants from the population of Rome (Italy) and 286 puerperae from another population from Central Italy were studied. RESULTS: The correlation coefficient between birth weight and placental weight is much higher in infants with low activity AK12-1 phenotype than in those with high activity AK11 phenotype. The difference between AK1 and AK12-1 is well marked only in newborns with a gestational age greater than 38 weeks and it is not influenced by sex, maternal age and maternal smoking. A similar pattern is observed with maternal AK1 phenotype. CONCLUSIONS: These results suggest that the difference in enzymatic activity between AK1 phenotypes influencing the equilibrium among ATP, ADP, AMP and adenosine could have an important role in a balanced development of feto-placental unit.