Achraf Jemli1, Oumaima Inoubli1, Fatma Trifa2,3, Anouar Mechri4, Ferid Zaafrane4, Lotfi Gaha4, Besma Bel Hadj Jrad1. 1. a Laboratory of Genetics, Biodiversity and Valorization of Bio-Resources , Higher Institute of Biotechnology of Monastir, University of Monastir , Monastir , Tunisia. 2. b Department of Biostatistics , Higher Institute of Biotechnology of Monastir, University of Monastir , Monastir , Tunisia. 3. c Laboratory of Biomass Valorization and Production of Eucaryotic Proteins , Center of Biotechnology of Sfax , Sfax , Tunisia. 4. d Laboratory of Psychiatry and Vulnerability to Psychoses - CHU Fatouma Bourguiba Monastir , University of Monastir , Monastir , Tunisia.
Abstract
BACKGROUND: Considering current scientific evidence about the significant role of chronic low grade inflammation in the physiopathology of schizophrenia, it has been hypothesized that changes in pro-inflammatory cytokines such as interferon gamma may have a significant role in the predisposition to schizophrenia. AIM: This study focuses on identifying whether the functional polymorphism of interferon gamma receptor 2 (IFNGR2) is a risk factor for the development of schizophrenia. METHODS: This study was conducted by the RFLP-PCR on a Tunisian population composed of 225 patients with different sub-types of schizophrenia and 166 controls. RESULTS: The IFNGR2 (Q64R) polymorphism analysis showed higher frequencies of minor homozygous genotype (RR) and allele (R) in all patients compared to controls (21.8% vs 10.2%; p = .006, OR = 2.54) and (44% vs 34.9%; p = .01; OR = 1.46), respectively. This correlation was confirmed only for males. This study also noted a significant increase of the mutated homozygous (RR) genotype and (R) allele frequencies of IFNGR2 in paranoid schizophrenics compared to controls (31.4% vs 10.2%; p = .001; OR = 3.34 and 47.2% vs 34.9%; p = .009; OR = 1.66, respectively). This increase remains significant after using binary logistic regression to eliminate confounding factors such as age and sex. Additionally, carriers of RR genotype have significant lower scores on the Scale of Assessment of Positive (SAPS) and negative (SANS) symptoms comparatively to the carrier of the QQ + QR genotypes, suggesting that the R recessive allele carriers could have milder symptoms. CONCLUSION: The IFNGR2Q64R polymorphism is correlated with male sex and paranoid schizophrenia. It is suggested that a chronic neuroinflammation may predispose to the paranoid schizophrenia development in men.
BACKGROUND: Considering current scientific evidence about the significant role of chronic low grade inflammation in the physiopathology of schizophrenia, it has been hypothesized that changes in pro-inflammatory cytokines such as interferon gamma may have a significant role in the predisposition to schizophrenia. AIM: This study focuses on identifying whether the functional polymorphism of interferon gamma receptor 2 (IFNGR2) is a risk factor for the development of schizophrenia. METHODS: This study was conducted by the RFLP-PCR on a Tunisian population composed of 225 patients with different sub-types of schizophrenia and 166 controls. RESULTS: The IFNGR2 (Q64R) polymorphism analysis showed higher frequencies of minor homozygous genotype (RR) and allele (R) in all patients compared to controls (21.8% vs 10.2%; p = .006, OR = 2.54) and (44% vs 34.9%; p = .01; OR = 1.46), respectively. This correlation was confirmed only for males. This study also noted a significant increase of the mutated homozygous (RR) genotype and (R) allele frequencies of IFNGR2 in paranoid schizophrenics compared to controls (31.4% vs 10.2%; p = .001; OR = 3.34 and 47.2% vs 34.9%; p = .009; OR = 1.66, respectively). This increase remains significant after using binary logistic regression to eliminate confounding factors such as age and sex. Additionally, carriers of RR genotype have significant lower scores on the Scale of Assessment of Positive (SAPS) and negative (SANS) symptoms comparatively to the carrier of the QQ + QR genotypes, suggesting that the R recessive allele carriers could have milder symptoms. CONCLUSION: The IFNGR2Q64R polymorphism is correlated with male sex and paranoid schizophrenia. It is suggested that a chronic neuroinflammation may predispose to the paranoid schizophrenia development in men.