[Effects of oxytocin pathway gene polymorphisms and adverse childhood experiences on emotion recognition in schizophrenia spectrum disorders]. / Effekty polimorfizma genov oksitotsinergicheskogo puti i neblagopriyatnogo detskogo opyta na raspoznavanie emotsii pri rasstroistvakh shizofrenicheskogo spektra.

OBJECTIVE: To study a role of the interaction of oxytocin pathway gene polymorphisms and adverse childhood experiences (ACE) in facial emotion recognition (FER) deficits in schizophrenia. MATERIAL AND METHODS: Patients with schizophrenia spectrum disorders (n=699) completed cognitive testing, which included a FER task. We determined patients' genotypes for common polymorphisms in three of the oxytocin pathway genes which were previously associated with face perception: OXTR (rs53576, rs7632287), CD38 (rs3796863) and ARNT2 (rs4778599). The presence of ACE in the patient's history was assessed via an analysis of medical records. RESULTS: In our sample, 49% of participants experienced ACE. ANCOVA adjusted for age and gender revealed a significant interaction effect of OXTR rs53576 with ACE on FER scores (F=11.51; p<0.001; η2p=0.02). The effect remained significant when accounting for cognitive functioning and negative symptoms. Carriers of the A allele without ACE recognized emotions worse than GG homozygotes without ACE (p=0.039) and carriers of the A allele with ACE (p=0.009). CONCLUSION: The results are consistent with the notion of the A (rs53576) allele's role in sensitivity to childhood experiences that influence the psychosocial development and can be used in further studies of the oxytocin treatment of social cognition and social adaptation of patients with schizophrenia.

[Genetic polymorphism of cytokines IL-1ß, IL-4 and TNF-α as a factor modifying the impact of childhood adversity on schizophrenia symptoms]. / Geneticheskii polimorfizm tsitokinov IL-1ß, IL-4 i TNF-α kak faktor, modifitsiruyushchii vliyanie neblagopriyatnogo detskogo opyta na simptomatiku shizofrenii.

OBJECTIVE: Based on the hypothesis that activation of the immune system is one of the mechanisms of influence of early environmental factors on the onset and course of schizophrenia, we investigated the effects of the interaction of childhood adversity and IL-1ß rs16944, IL-4 rs2243250 and TNF-α rs1800629 polymorphisms on schizophrenia symptomatology. MATERIAL AND METHODS: The sample consisted of 546 patients with schizophrenia spectrum disorders. The presence of childhood adversity was determined based on the analysis of medical records and a questionnaire completed by the patient. We used the 5-factor model of the Positive and Negative Syndrome Scale (PANSS) with the nested two-factor negative syndrome model. RESULTS: After adjusting for multiple comparisons, a significant effect of the interaction of childhood adversity and TNF-α on the cognitive/disorganization factor was found, with a difference between genotypes in the group without childhood adversity (pFDR <0.018; η2p=0.03). A significant effect of the interaction of childhood adversity and genotype on the cognitive disorganization syndrome was established (F=5.87; p=0.003; η2p=0.03). Stereotyped thinking and avolition on PANSS had the highest correlations with cognitive disorganization factor (ro=0.84 and ro=0.82, respectively) and the highest significance of differences depending on the interaction of genotype and childhood adversity (Kruskal-Wallis test, H=12.28, p=0.006 and H=12.79, p=0.005, respectively). CONCLUSION: Childhood adversity modifies the relationship between the pathogenesis of schizophrenia and the TNF-α promoter polymorphism rs1800629, which is also an enhancer of another 60 genes located in the major histocompatibility complex.

Dataset on negative symptoms factors in patients with schizophrenia.

Schizophrenia is a severe mental disorder characterized by positive and negative symptoms. The negative symptoms are highly relevant to the disease course and outcome. Because negative symptoms show considerable heterogeneity, there is substantial interest in elucidating the negative symptom domains that are characteristic of patient subgroups. It has been proposed that patients with schizophrenia should be classified into deficit and non-deficit groups based on the severity of their negative symptoms. Another method suggested the assessment of the factor structure of negative symptoms to understand its mechanisms. Factor analysis of the different negative symptom rating scales reveals two distinct negative symptom subdomains: diminished expression (DE) and avolition/apathy (AA). These characteristics suggest different pathophysiological mechanisms for the development of AA and DE. We present a large dataset of negative symptom factors calculated for 3006 patients with schizophrenia in the Russian population. Sex, age, age at disease onset and data of birth, including season of birth (SOB), family history of schizophrenia are presented. Negative symptoms were assessed with the Positive and Negative Syndromes Scale (PANSS). We calculated negative symptoms factors as suggested by Liemburg et al. (2013). The data will be useful in assessing the impact of such factors as sex, season of birth (SOB) and family history on the scores of negative symptoms subdomains; such data can help us to better understand the heterogeneity of the negative symptoms of schizophrenia.

[Associations between the oxytocinergic system genes, perinatal complications and interpersonal relationships in patients with schizophrenia]. / Issledovanie svyazi mezhdu genami oksitotsinergicheskoi sistemy, perinatal'nymi oslozhneniyami i formirovaniem mezhlichnostnykh otnoshenii u bol'nykh shizofreniei.

OBJECTIVE: To search for the associations between genes of the oxytocinergic pathway and psychosocial functioning in schizophrenia, namely, the ability of schizophrenic patients to form interpersonal relationships, taking into account the influence of such an environmental factor as perinatal complications. MATERIAL AND METHODS: The study included 383 people (140 women and 243 men, mean age 32.6±11.4 years), of whom 107 had a history of perinatal complications, and 276 did not. Psychosocial functioning was assessed using the Personal and social relationships domain of The Personal and Social Performance scale (PSP). Polymorphisms rs53576, rs4686302, rs1042778 in the oxytocin receptor gene (OXTR) and polymorphism rs3796863 in the transmembrane glycoprotein (CD38) gene were genotyped. RESULTS: There is the association between the OXTR rs53576 polymorphism and scores on the interpersonal relations domain (p=0.005). Significant differences are found between carriers of the GG genotype and carriers of the A allele (p=0.003). In the group without perinatal complications, the genotype does not have a significant effect on PSP score. There are no associations between other polymorphisms and the level of interpersonal relationships in any of the studied groups. CONCLUSION: The results are in accordance with the notions accepted on the basis of numerous evidences that link the genes of the oxytocinergic system with social behavior. We obtained new data on the influence of the known polymorphism OXTR rs53576 on the phenotype, which has not been studied previously in this aspect - the ability to form interpersonal relationships in patients with schizophrenia, while it was shown that the effect of the genotype depends on the environmental risk factor (perinatal complications).

[Prognosis of the functional outcome of schizophrenia using a multigene panel]. / Otsenka prognoza funktsional'nogo iskhoda shizofrenii s pomoshch'yu mul'tigennogo testa.

OBJECTIVE: To compare the groups of schizophrenic patients with different levels of functional outcome and different frequency of risk variants in polymorphic loci of five candidate genes to create a multigene panel and to test its predictive ability for long-term outcome of the disease. MATERIAL AND METHODS: According to the proposed typology, the patients included in the studies were divided into three groups, which differed in the level of social functioning. Group 1 was characterized by the highest level, in group 2 this indicator was significantly lower, and in group 3 the lowest. The multigenic panel included genes for serotonin receptor type 2a (5-HTR2A T102C), serotonin transporter (5-HTTLPR), C-reactive protein (CRP -717A>G), angiotensin II receptor type 1 (AGTR1 A1166C), and brain neurotrophic factor (BDNF Val66Met). A multi-gene risk score was calculated for each patient by summing the total number all his/her risk alleles. For each polymorphism, a score of 2 was assigned to homozygous high-risk genotypes, a score of 1 to heterozygous genotypes and a score of 0 to homozygous low-risk genotype. Accordingly, the multi-gene risk score for a patient could vary from 0 to 10 risk alleles. RESULTS: A significant effect of the group on the multi-gene risk score was shown (p<0.0001). Between-group differences were significant as well (p<0.01). In group 1, there were no carriers of ≥6 risk alleles, and the number of carriers of less than 5 alleles exceeded 50%. In group 2, the number of carriers of ≥6 risk alleles was 19.4%, and in group 3 - 31.7%. Moreover, in these groups there were no carriers of 0-2 risk alleles, while in group 1 their number was 20.7%. CONCLUSION: The multi-gene risk score predicts the level of functional outcome in patients with schizophrenia. In the case of a smaller number of risk alleles (0-4) in an individual, a favorable functional outcome can be predicted with a high probability in the long-term period of the disease.

[Structure of schizotypal traits in the Russian population]. / Struktura shizotipicheskikh chert v rossiiskoi populyatsii.

Establishing the structure of schizotypal traits and its cross-cultural and demographic universality is an important condition for increasing the effectiveness of prognosis of schizophrenic spectrum disorders and basic research on their etiology. The present study aimed to explore the structure of schizotypal traits measured by the Schizotypal Personality Questionnaire (SPQ-74) in the Russian population. Exploratory and confirmatory factor analyses of the factor structure of SPQ-74 were performed using a sample of 1316 people of a wide age range. It is shown that, in the Russian population, the four-factor «paranoid¼ model of N. Stefanis et al. had the best fit for the data. The multivariate confirmatory analysis evidenced the gender invariance of the model.

Copy number variations of satellite III (1q12) and ribosomal repeats in health and schizophrenia.

OBJECTIVE: Earlier we studied the copy number variations (CNVs) of ribosomal repeat (rDNA) and the satellite III fragment (1q12) (f-SatIII) in the cells of schizophrenia patients (SZ) and healthy controls (HC). In the present study we pursued two main objectives: (1) to confirm the increased rDNA and decreased f-SatIII content in the genomes of enlarged SZ and HC samples and (2) to compare the rDNA and f-SatIII content in the same DNA samples of SZ and HC individuals. METHODS: We determined the rDNA CN and f-SatIII content in the genomes of leukocytes of 1770 subjects [HC (N = 814) and SZ (N = 956)]. Non-radioactive quantitative hybridization method (NQH) was applied for analysis of the various combinations of the two repeats sizes in SZ and HC groups. RESULTS: f-SatIII in human leukocytes (N = 1556) varies between 5.7 and 44.7 pg/ng DNA. RDNA CN varies between 200 and 896 (N = 1770). SZ group significantly differ from the HC group by lower f-SatIII content and by rDNA abundance. The f-SatIII and rDNA CN are not randomly combined in the genome. Higher rDNA CN values are associated with higher f-SatIII index values in SZ and HC. The f-SatIII variation interval in SZ group increases significantly in the subgroup with the high rDNA CN index values (>300 copies). CONCLUSION: Schizophrenia patients' genomes contain low number of f-SatIII copies corresponding with a large ribosomal repeats CN. A scheme is proposed to explain the low f-SatIII content in SZ group against the background of high rDNA CN.

Data on association of the variation (rs1344706) in the ZNF804A gene with schizophrenia and its symptoms in the Russian population.

The polymorphism rs1344706 in the ZNF804A gene is one of the best-supported risk variants for schizophrenia. The association between ZNF804A rs1344706 and the disease was demonstrated in many studies but only few of them investigated large samples (above 2000 patients and controls). Data presented show the genotypic distribution of ZNF804A rs1344706 in 1265 patients with schizophrenia and 1051 healthy controls from the Russian population. Statistical analysis confirmed the association between rs1344706 and schizophrenia (p = 0.034). The frequency of the risk genotype AA was significantly higher in the group of patients compared to that in controls. In addition, the article provides the data on the severity of schizophrenia symptoms measured with the Positive and Negative Syndrome scale (PANSS) in 951 patients. The severity of symptoms was significantly higher in the carriers of the risk genotype AA compared to the AC genotype and the CC genotype.

[Genetic variations associated with premorbid personality in patients with schizophrenia]. / Geneticheskie polimorfizmy, assotsiirovannye s razlichnoi stepen'iu vyrazhennosti premorbidnykh lichnostnykh anomalii u bol'nykh shizofreniei.

AIM: To search for genetic variants associated with premorbid personality in patients with schizophrenia. MATERIAL AND METHODS: The sample included 272 men diagnosed with schizophrenia or schizoaffective disorder. Patients were divided into 3 groups based on premorbid personality difficulties: mild (group 1, n=110), moderate (group 2, n=113), marked (group 3, n=49). The following polymorphisms were genotyped: 5-HTR2A (T102C), 5-HTTLPR, BDNF (Val66Met), CRP (-717A>G). RESULTS: A significant increase in the frequency of the CC (5-HTR2A T102C), LL (5-HTTLPR) and Met/Met (BDNF Val66Met) genotypes was identified in group 3 compared to group 1. Frequencies of CC and LL genotypes were significantly higher in group 2 compared to group 1 as well. The differences between group 2 and group 3 were found only for the Met/Met genotype. There were no between-group differences in the frequencies of CRP (-717A>G) genotypes. CONCLUSION: 5-HTR2A (T102C), 5-HTTLPR, BDNF (Val66Met) polymorphisms previously reported to modify schizophrenia course are also associated with premorbid personality in schizophrenic patients.

[The interaction effect of ANKK1/DRD2 TaqIA and HTR2C Cys23Ser on approach motivation in schizophrenic patients and normals]. / Éffekt vzaimodeistviia polimorfizmov ANKK1/DRD2 TaqIA i HTR2C Cys23Ser na pobuditel'nuiu motivatsiiu u bol'nykh shizofreniei i zdorovykh.

AIM: To evaluate the association of the DRD2 gene and DRD2 x HTR2C interaction with hedonic and activational aspects of approach motivation in schizophrenia. MATERIAL AND METHODS: Genotypes at polymorphic loci DRD2 rs1800497 and HTR2C rs6318 (Cys23Ser) were identified in a sample that included 174 patients with schizophrenic spectrum disorders and 268 healthy subjects without a family history of psychoses. The participants completed the BIS/BAS and Temporal Experience of Pleasure Scale (TEPS). RESULTS AND CONCLUSION: A MANCOVA with sex and age as covariates revealed the effect of the 'DRD2 x HTR2C x diagnosis' interaction on the BAS scores (p=0.033). The effect was significant for the Fun-Seeking and Drive scales. Among patients, the carriers of the DRD2 TT/CT x HTR2C GG/G genotype showed the highest scores on the both scales, and those with the minor alleles in the two loci had the lowest ones. Differences between these groups were nominally significant for both the Fun-Seeking and Drive, but did not survive the correction for multiple comparisons. Among controls, subjects without minor alleles demonstrated the highest scores on these two scales. They differed significantly from the carriers of the DRD2 TT/CT+HTR2C GG/G genotype on the Fun-Seeking (p=0.008). No effects of DRD2 and HTR2C on TEPS scores were found. In general, the results of the study can be interpreted in favor of the hypothesis about the role of the HTR2C and DRD2 genes interaction in the variability of the activational aspects of approach motivation in schizophrenia and healthy subjects. However, the lack of differences survived correction for multiple comparisons makes it difficult to interpret the revealed effects.

[A study on the association of genes for pro-inflammatory cytokines and depression]. / Sviaz' genov provospalitel'nykh tsitokinov s depressiei.

AIM: To study the association between proinflammatory cytokine genes and depression. MATERIAL AND METHODS: IL-1B С-511T and TNF-a G-308A gene polymorphisms were studied in patients diagnosed with depression and age and sex-matched healthy controls. RESULTS AND CONCLUSION: The IL-1B С-511T and TNF-a G-308A polymorphisms were associated with depression; CC genotype (р=0,001, OR=1.9 CI 1,3-2,7) and GG genotype (р=0,001, OR=3,0 CI 1,8-4,9) were the risk factors. The results suggest that immune factors may play a role in the development of depression. The authors highlight the role of clinical polymorphism of depression that makes it difficult to form homogenous groups of patients and to select phenotypes for biological studies.

ROS-Induced DNA Damage Associates with Abundance of Mitochondrial DNA in White Blood Cells of the Untreated Schizophrenic Patients.

OBJECTIVE: The aim of this study was (1) to examine the leukocyte mtDNA copy number (CN) in unmedicated (SZ (m-)) and medicated (SZ (m+)) male patients with paranoid schizophrenia (SZ) in comparison with the healthy male controls (HC) and (2) to compare the leukocyte mtDNA CN with the content of an oxidation marker 8-oxodG in lymphocytes of the SZ (m-) patients. METHODS: We evaluated leukocyte mtDNA CN of 110 subjects with SZ in comparison with 60 male HC by the method qPCR (ratio mtDNA/nDNA (gene B2M) was detected). SZ patients were divided into two subgroups. The patients of the subgroups SZ (m+) (N = 55) were treated with standard antipsychotic medications in the hospital. The patients of the subgroup SZ (m-) (N = 55) were not treated before venous blood was sampled. To evaluate oxidative DNA damage, we quantified the levels of 8-oxodG in lymphocytes (flow cytometry) of SZ (m-) patients (N = 55) and HC (N = 30). RESULTS: The leukocyte mtDNA CN showed no significant difference in SZ (m+) patients and HC. The mtDNA CN in the unmedicated subgroup SZ (m-) was significantly higher than that in the SZ (m+) subgroup or in HC group. The level of 8-oxodG in the subgroup SZ (m-) was significantly higher than that in HC group. CONCLUSION: The leukocytes of the unmedicated SZ male patients with acute psychosis contain more mtDNA than the leukocytes of the male SZ patients treated with antipsychotic medications or the healthy controls. MtDNA content positively correlates with the level of 8-oxodG in the unmedicated SZ patients.

Abundance of ribosomal RNA gene copies in the genomes of schizophrenia patients.

OBJECTIVE: The ribosome is a critical component of the translation machinery. The key component of ribosomes is ribosomal RNA (rRNA). Dysregulation of rRNA biogenesis has been implicated in some human diseases. One of the factors affecting rRNA biogenesis is the ribosomal RNA genes (rDNA) copy number in the genome. The aim of this study was to examine the rDNA copy number (CN) variation in the genomes of patients with schizophrenia (SZ) compared to healthy controls (HC). METHODS: We evaluated rDNA CN in leukocytes of 179 subjects with SZ (108 male/71 female) in comparison with 122 HC (60 male/62 female) using two techniques: qPCR and nonradioactive quantitative hybridization (NQH), which is based on the use of biotinylated rDNA probes. RESULTS: rDNA CN (NQH) and rDNA CN (qPCR) was higher in SZ patients than in controls (median 542 vs 384, p=10-25 and median 498 vs 370, p=10-12). NQH was experimentally proved to be less sensitive to severe DNA damage than qPCR. The more DNA damage, the higher the ratio R=CN (NQH)/CN (qPCR). 15% of the SZ patients had significantly higher rDNA damage degree than the HC. CONCLUSION: Genomes of some SZ patients contain more ribosomal genes than those of HC. The elevated ribosomal genes copy number in human genome can be one of the genetic factors of schizophrenia development. This hypothesis requires further experimental studies to be corroborated or disproved.

[Epigenetic research of cognitive deficit in schizophrenia: some methodological considerations]. / Épigeneticheskie issledovaniia kognitivnogo defitsita pri shizofrenii: nekotorye metodologicheskie problemy.

AIM: To highlights the problems of assessing cognitive deficits in schizophrenia, relevant to the epigenetic, as well as a wide range of other approaches to the search for biological bases of cognition. MATERIAL AND METHODS: The literature on the weaknesses in the evaluation of cognitive functions in patients with schizophrenia are summarized and discussed. The analysis is illustrated by our experience in developing a cognitive battery and a sample to examine relationships between DNA methylation in blood cells and cognitive deficits in schizophrenia. RESULTS AND CONCLUSION: It has been shown that to assess cognitive deficits in patients and to reduce the influence of confounders in epigenetic analysis it is necessary (1) to use a battery with the existing co-normative data in the target population, which allows to evaluate representativeness of control and patients included in the study sample, (2) to verify the theoretically driven battery structure using normative population and a cohort of patients, (3) to balance groups of cases and controls on the number, age and sex, for which an individual matching of cases and controls is best suited, (4) to conduct an additional statistical analysis controlling for education and smoking.

[Effect of cytokine genes and season of birth on personality]. / Vliianie genov tsitokinov i sezona rozhdeniia na nekotorye osobennosti lichnosti.

AIM: To evaluate the interaction effects of season of birth and immune system genes on the personality traits 'Novelty seeking' (NS) and 'Self-directedness' (SD). Based on results on an influence of the immune system on the brain processes, the authors hypothesized that the interaction of immune system genes and season of birth, which is relevant for immune phenotype, can contribute to the development of personality traits. MATERIAL AND METHODS: NS and SD were measured in 336 healthy volunteers, aged from 16 to 67 years, using the Temperament and Character Inventory (TCI-125). IL1B C3954T, IL4 C-589T, IL13 C1112T and TNFA G-308A polymorphisms were genotyped. RESULTS: An interaction effect of IL4 C-589T and season of birth on the personality traits was found (F2,322=6.03, pcorr=0.011, η2=0.04). Carriers of the minor allele T, who were born in winter, had lower NS and higher SD. There was a nominal main effect of genotype on SD (F=5.44, p=0.020) as well, with higher SD scores in carriers of the allele T compared to the CC genotype. CONCLUSION: The results suggest that the etiology of personality and immune characteristics can share common genetic elements including IL-4.

[A role of interactions between N-methyl-D-aspartate and dopamine receptors in facial emotion recognition impairment in schizophrenia]. / Rol' vzaimodeistviia genov NMDA- i dofaminovykh retseptorov v narushenii raspoznavaniia émotsional'noi mimiki pri shizofrenii.

AIM: To search for genetic mechanisms of facial emotion recognition (FER) impairment, one of the features of schizophrenia that affects social adaptation of patients. Based on the view implicating the interplay between dopaminergic and glutamatergic systems into the pathogenesis of schizophrenia, authors explored the interaction effects of the C366G polymorphism in the GRIN2B gene encoding NMDA receptor subunit NR2B with ANKK1/DRD2 Taq1A and 48-VNTR DRD4 polymorphisms on FER. MATERIAL AND METHODS: GRIN2B -DRD2 interaction effects were studied in a sample of 237 patients and 235 healthy controls, GRIN2B - DRD4 in 268 patients and 208 controls. RESULTS AND CONCLUSION: Both effects were significant in combined samples of patients and controls (GRIN2B X DRD2, F=4.12, p=0.043; GRIN2B X DRD4, F=6.43, p=0.012). Further analysis confirmed the interaction effect of GRIN2B and DRD2 polymorphisms on FER in patients with schizophrenia. In patients with a less efficient allele of the DRD2 in the absence of the minor allele of the GRIN2B C366G polymorphism, the results were close to normal values while patients with minor alleles of both polymorphisms showed the worst results. This finding is in line with the conceptions on a possible role of NMDA-receptor hypofunction and D2-mediated regulation of NMDA-receptor activity in FER impairments in schizophrenia.

Association of -717A>G Polymorphism in the C-Reactive Protein Gene (CRP) with Schizotypal Personality Traits.

Associations between schizotypal traits and genes coding for inflammation markers (Creactive protein and TNF-α) were studied in 222 healthy men who completed the Schizotypal Personality Questionnaire (SPQ-74). CRP -717A>G and TNFα -308 G>A polymorphisms were genotyped. Carriers of low-active allele G of the CRP gene differed from subjects with genotype AA by a trend toward more manifest schizotypal traits in general and scores on the Interpersonal factor, which corresponds to negative syndrome in schizophrenia, and Constricted affect and Odd behavior scales. These results could be interpreted in favor of the hypothesis on a compensatory increase of CRP concentrations in subjects with abnormalities of CNS development that predispose to schizophrenia.

[A study of the effect of the genes of inflammatory proteins on basic personality dimensions]. / Issledovanie effekta genov vospalitel'nykh faktorov na bazovye cherty lichnosti.

AIM: The present research examines the association between two basic dimensions of personality and genes of inflammatory cytokines and mediators reported to be elevated in schizophrenia and affective disorders. Genes of interleukin-1B (IL-1B), interleukin-6 (IL-6), tumor necrosis factor alpha (TNF-α), C-reactive protein (CRP) and alpha 1-antitrypsin (A1AT) were studied. MATERIAL AND METHODS: A total of 639 healthy subjects, aged from 17 to 69 years, participated in the study. The following polymorphisms were genotyped: IL-1B С-511Т (rs16944) and С3954Т (rs1143634), IL-6 G-174C (rs1800795), TNF-α G-308A (rs1800629), CRP (rs279452), A1AT 374G/A (rs709932). Basic personality dimensions Extraversion and Neuroticism were assessed using the Eysenck Personality Inventory. RESULTS AND CONCLUSION: The levels of Extraversion and Neuroticism were not associated with IL-1B, IL-6, TNF-α G and CRP polymorphisms. The association between the A1AT 374G/A polymorphism and Extraversion (р=0.036) was shown. There was a trend towards the association between the A1AT 374G/A polymorphism and Neuroticism (p=0,05) in women. Because this is the first study of the effect of IL-1B, IL-6, TNF-α and A1AT on personality dimensions, the results should be considered as preliminary and need to be replicated.

[The association between the GRIN2B gene and verbal fluency and impairment of abstract thinking in schizophrenia].

OBJECTIVE: To search for the association between the GRIN2B gene and signs of thought and speech disorders which may be the result of decreased accessibility to the mental lexicon. MATERIAL AND METHODS: The association between the GRIN2B polymorphism rs7301328 with semantic verbal fluency and five symptoms of thought and speech disorders, as assessed with the PANSS, was studied in 552 patients with schizophrenia-spectrum disorders. RESULTS AND CONCLUSION: There was the association of the GRIN2B gene with verbal fluency and the PANSS item «Difficulty in Abstract Thinking¼. The association was not modified by verbal fluency. The results suggest that the GRIN2B gene may modify the linguistic processes involved in the retrieval of information from the mental lexicon on the basis of semantic traits and, moreover, contribute to the variability of clinical symptoms of impairment of abstract thinking in patients with schizophrenia. The heterozygous genotype may be protective against the development of thought and speech disorders.