Synaptosomal-associated protein (SNAP-25) polymorphisms and response to olanzapine in schizophrenia patients

Abstract

Introduction: Genetic factors may influence response to antipsychotic treatment in patients with schizophrenia. The synaptosomal-associated protein of 25 kDa (SNAP-25) gene may be an interesting candidate gene regarding clinical outcome with antipsychotics. SNAP-25 is a presynaptic plasma membrane protein and an integral component of the vesicle docking and fusion machinery mediating secretion of neurotransmitters (1). Muller et al. reported that Mn1I T/G, TaiI T/C polymorphisms in the SNAP-25 gene were associated with both antipsychotic drug response and drug induced weight gain (3). We aimed to evaluate the association of SNAP-25 (Mn1I T/G and DdelI T/C) polymorphisms with response to olanzapine in our study. Yöntem: Our study comprised 86 unrelated subjects who strictly met DSM-IV criteria for schizophrenia and all were of Turkish origin. Genetic analyses were performed and patients were evaluated with rating scales. Results: When we compare the groups TT with TG+ GG patients with T/T genotype had better response to olanzapine for SANS scale in SNAP-25 Mn1I polymorphism. Also patients with TC+ CC genotype were responded better than patients with TT genotype for SNAP-25 DdelI polymorphism. Conclusion: Muller et al. reported that MnlI and TaiI polymorphisms (but not Ddel polymophism) were associated with response to olanzapine. Interestingly we found an association between SNAP-25 DdelI T/C polymorphism and response to olanzapine treatment. SNAP-25 gene polymorphisms might be related to antipsychotic response but further studies were needed.