NOS1AP Gene Variants and Their Role in Metabolic Syndrome: A Study of Patients with Schizophrenia.

Metabolic syndrome (MetS) is common among schizophrenia patients, and one of MetS's causes may be an imbalance in nitric oxide regulation. In this study, we examined associations of three polymorphic variants of the nitric oxide synthase 1 adapter protein (NOS1AP) gene with MetS in schizophrenia. NOS1AP regulates neuronal nitric oxide synthase, which controls intracellular calcium levels and may influence insulin secretion. The aim of the investigation was to study polymorphic variants of the NOS1AP gene as possible markers of MetS in patients with schizophrenia. A total of 489 Caucasian patients with schizophrenia (ICD-10) from Siberia (Russia) were included in the study, and 131 (26.8%) patients had MetS (IDF classification, 2007). The participants were genotyped for three single-nucleotide polymorphisms in NOS1AP (rs12143842, rs10494366, and rs12029454). Logistic regression was used for association analysis. Single-nucleotide polymorphisms, sex, and age served as covariates; the dependent variable was the coded parameter of the presence/absence of MetS. Polymorphisms rs12143842 and rs10494366 showed a stable association even after Bonferroni's correction for multiple comparisons (p = 0.005 and 0.002, respectively), indicating a statistically significant contribution of these polymorphic variants to the pathogenesis of MetS. Our results suggest that in patients with schizophrenia, NOS1AP may be involved in MetS pathophysiology.

The Role of Glutamatergic Gene Polymorphisms in the Clinical Phenotypes of Schizophrenia.

BACKGROUND: Personal variations in genetic risk for schizophrenia relate to its phenotypic heterogeneity-both in disorder development and clinical manifestations. Abnormal glutamatergic neurotransmitter system functioning is integrated in the pathogenesis of schizophrenia. METHODS: A sample of 805 Russian schizophrenia patients from the Siberian Federal region was investigated. We examined the association of 39 single nucleotide polymorphisms in eight genes (GRIN2A, GRIN2B, SLC1A2, SLC1A3, SLC17A7, GRM3, GRM7, and GRM8) involved in the glutamatergic system with the development of clinical heterogeneity of schizophrenia. The MassARRAY Analyzer 4 was used for genotyping. RESULTS: GRIN2A rs11644461, rs8057394 and GRIN2B rs7313149 are associated with the continuous type of schizophrenia. The GRIN2A rs8057394*G allele is a relative risk factor (p = 0.019) for developing the continuous type of schizophrenia. We found a nominally significant association between negative symptoms of schizophrenia and SLC17A7 rs62126236. The SLC17A7 rs62126236*T allele has a protective effect (p = 0.039) against predominant negative symptoms in schizophrenia. The total Positive and Negative Syndrome Scale (PANSS) scores were significantly associated with GRIN2A rs9788936 after adjusting for multiple testing (p = 0.001). CONCLUSIONS: In this study the contribution of the glutamatergic gene polymorphisms to the clinical heterogeneity of schizophrenia has been demonstrated.

Dehydroepiandrosterone sulphate as a putative protective factor against tardive dyskinesia.

BACKGROUND: Tardive dyskinesia (TD) is a potentially irreversible consequence of long term treatment with antipsychotic drugs which is according to a well-known theory believed to be related to oxidative stress induced neurotoxicity. Dehydroepiandrosterone (DHEA) is an endogenous antioxidant with neuroprotective activity. The biosynthesis of DHEA depends upon the activity of cytochrome P450c17α (CYP17). The gene that encodes for CYP17 has a (T34C) single nucleotide polymorphism which enhances CYP17 transcription and expression. OBJECTIVE: To test the hypothesis that carriership of a more active CYP17 variant would result in higher DHEA(S) levels and protect against neurotoxicity which results in orofaciolingual TD (TDof), limb-truncal TD (TDlt) or both (TDsum). METHOD: Tardive dyskinesia was assessed cross-sectionally in 146 Caucasian psychiatric inpatients from Siberia. RESULTS: Patients who are carriers of the Cyp17 genotype CC have less chance of developing TD compared to patients who are carriers of the Cyp17 genotypes TC or TT (p<0.05). However, these carriers have significant lower circulating DHEAS levels compared to carriers of the Cyp17 genotypes TC and TT (p<0.05). Conversely, carriers of the CYP17 T-allele have significant elevated DHEAS levels. After correcting for gender and age no significant relationship between Cyp17 genotype CC, the T-allelle and the C-allele and the DHEAS concentration of patients was observed. CONCLUSIONS: Although an association between the CYP17 CC genotype and TD is indicated, our findings do not support the hypothesis that this is mediated through increased DHEA(S) levels. We believe that the relationship between this polymorphism and neuroprotective effects of steroids is more complex and cannot be elucidated without taking the posttranslational regulation of the enzyme into account.