These results suggest that the interaction effects between 5-HTTLPR and TNFA -238/-308 polymorphisms gives no significant contribution to the susceptibility to schizophrenia, and is not associated with clinical variables, antipsychotic treatment response and psychopathological features, except for family history of disease, at least in the Korean population.
A serotonin transporter gene linked polymorphic region (5-HTTLPR) has been investigated in several genetic association studies, including studies of schizophrenia and suicidality.
Our data imply that following completion of the International HapMap Project, a comprehensive evaluation of a set of markers that fully characterize the linkage disequilibrium relationships at the SLC6A4 gene should be tested in large well-characterized clinical samples in order to understand the role of this gene in schizophrenia susceptibility.
This positive finding further supports the proposition that the 5-HTT-VNTR allele 12 is a risk factor for schizophrenic disorders in Chinese populations, although the effect is weak.