Possible association of the short allele of the serotonin transporter promoter gene polymorphism (5-HTTLPR) with violent suicide

There is abundant evidence that the serotonin (5-HT) system is modulating m ood and several behavioural traits and that disturbances in the regulation of this system can be associated with severe behavioural malfunctions, as a ggressive implusive and suicidal behaviour.(1) Recently a functional polymo rphism in the promoter region of the serotonin transporter gene (5-HTTLPR) was identified(2) and the presence of one or two short alleles was associat ed with anxiety-related personality traits(3) and several psychiatric distu rbances, such as affective disorder(4) or severe alcohol dependence.(5) Wit h respect to the importance of the 5-HT transporter in serotonergic transmi ssion, we have genotyped the DNA of 58 Caucasian suicide victims (with unkn own psychiatric diagnoses) and 110 healthy controls for the biallelic funct ional polymorphism in the 5-HTTLPR. We found a highly significant increased frequency of suicide victims being carriers of one or two short alleles (F isher's Exact Test, two sided, P = 0.0003), which suggests that a genetical ly altered protein function within the serotonergic pathway might be involv ed in suicidality, independently from the clinical diagnosis.