The BDNFval66met polymorphism and individual differences in temperament in 4-month-old infants: A pilot study

•Temperament is defined as biologically based individual differences in behavioral traits.•Genetic polymorphisms might affect temperament, but there is no evidence for the BDNFval66met.•The BDNFval66met-temperament association was assessed in 4-month-old healthy full-term infants.•The presence of at-least one met allele associated with lower regulatory capacities.•The BDNFval66met is suggested to be included in future studies on genetic-temperament associations.

Individual differences in infants' temperament are under genetic control. We investigated the association between brain-derived-neurotrophic-factor (BDNFval66met) polymorphism and temperament in 63 full-term infants. Met-carriers (N = 25) had lower Regulatory capacities compared to val-homozygotes (N = 38). These findings suggest that the BDNF polymorphism affects early temperament individual differences.