Serotonin transporter polymorphisms and persistent, pervasive childhood aggression

OBJECTIVE: The purpose of this study was to examine the potential association of the serotonin transporter (5-HTT) gene and childhood aggression by testing the 5-HTT variable-number-tandem-repeat and serotonin transporter promoter polymorphism (5-HTTLPR), including the recently discovered Lg allelic variant of 5-HTTLPR. METHOD: Clinically referred children displaying extreme aggression, with a minimum 2-year history, were genotyped for 5-HTTLPR (N=77) and 5-HTT variable-number-tandem-repeat (N=78). Analyses compared genotype frequencies of the aggressive children with healthy comparison subjects. RESULTS: The "low expressing" genotypic variants of the 5-HTTLPR polymorphism (S/S, Lg/S, Lg/Lg) were significantly associated with childhood aggression. CONCLUSIONS: This is the first study to report a significant association between the 5-HTTLPR gene and childhood aggression.