SUSCEPTIBILITY FOR SCHIZOPHRENIA IS NOT INFLUENCED BY A FUNCTIONAL INSERTION DELETION VARIANT IN THE PROMOTER OF THE SEROTONIN TRANSPORTER GENE/

possible dysregulation of serotonergic neurotransmission has been impl icated in the aetiology of schizophrenic psychoses. In the present stu dy we analysed allelic and genotypic variations of a recently describe d functional polymorphic region in the promoter of the human serotonin transporter gene (5-HTTLPR) and a variable tandem repeat (VNTR) in in tron 2 of the 5-HTT gene. We investigated 413 unrelated individuals, 1 80 schizophrenic patients and 233 blood donors as controls. With regar d to the 5-HTTLPR, both the schizophrenic and the control group did no t significantly differ between genotype frequencies (chi(2), p = 0.920 ) and allele frequencies (chi(2), p = 0.836). The odds ratio for subje cts with schizophrenia who were homozygous for the short allele was 1. 04 (95% CI 0.59-1.84), No evidence of allelic association to specific schizophrenia subtypes was found, The 5-HTT associated VNTR also showe d no significant differences between either the allelic or the genotyp ic distributions. Haplotype analysis revealed a significant overall li nkage disequilibrium at a level of p = 0.00004. Our findings indicate that both polymorphisms are unlikely to play a substantial role in the genetic predisposition to schizophrenic disorders.