Ak(1) genetic polymorphism and season of conception

Objective: The season of conception affects human reproduction, intrauterine growth, neonatal parameters, sex ratio, cognitive development and, in adult life, performance in many fields. Associations between polymorphic enzymes and season of conception have been also reported. In this study we searched for a possible association between season of conception and adenylate kinase locus 1 (Ak(1)).

Study design: Two samples of 381 and 248 consecutively newborn infants from two Italian cities with different geographical positions and climatic conditions were considered. Three way contingency table analysis and Student t-test analysis were performed.

Results: Ak(1)2-1 phenotype is more frequent in males conceived in the summer-autumn period than in those conceived in winter-spring and this association depends on maternal Ak(1) phenotype (p=0.001). There is also an interaction between season of conception and Ak(1) phenotype concerning their effects on sex ratio and birth weight.

Conclusion: The present data suggest a complex interaction involving seasonal cycles, maternal and foetal Ak(1) genotype and sex of foetus concerning their effects on intrauterine selection and neonatal parameters.