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

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

Attention deficit hyperactivity disorder associaton with synaptosomal-associated protein (snap-25) polymorphisms

Introduction: The synaptosomal-associated protein of 25 kDa (SNAP-25) gene is a presynaptic plasma membrane protein and an integral component of the vesicle docking and fusion machinery mediating secretion of neurotransmitters (1). Previously, several studies reported association between SNAP-25 and attention deficit hyperactivity disorder (ADHD) (2). We investigated whether these SNAP-25 polymorphisms (Mn1I T/G and DdelI T/C) were also associated with ADHD in the Turkish population. Method: Our study comprised unrelated 79 subjects who met DSM-IV criteria for ADHD and 73 controls and all were of Turkish origin. Genetic analyses were performed and patients were evaluated with Wender-Utah and Turgay rating scales. Results: SNAP-25 DdelI polymorphism was not associated with ADHD but there was a statistically significant difference between ADHD patients and controls for SNAP-25 Mn1l polymorphism (p<0.05). For SNAP-25 Mn1l polymorphism patients with GG genotype had higher average of Wender-Utah and Turgay scores than patients with TT and TG genotype. Conclusion: We detected a significant association of the MnlI polymorphism in our ADHD sample which was similar to previous findings (2). Our study also revealed that SNAP-25 Mn1l polymorphism was also associated with symptom severity of ADHD. This study is also, the first report on the association of SNAP-25 with ADHD in the Turkish population