Interleukin-10 gene promoter polymorphism in patients with schizophrenia in a region of East Turkey

• Published in: The world journal of biological psychiatry 2009, Vol.10 (4_2), p.461-468
• Main Authors: Ozbey, Ulku, Tug, Esra, Namli, Mustafa
• Format: Article
• Language: English
• Subjects: Adult; Alleles; Biological psychiatry; Chromosomes, Human, Pair 1 - genetics; cytokines; Female; Gene Frequency - genetics; Genetic Markers - genetics; Genetic Predisposition to Disease - genetics; genetics; Genetics, Population; Genotype; Haplotypes - genetics; Homozygote; Humans; Interleukin-10 - genetics; Male; Middle Aged; polymorphism; Polymorphism, Genetic - genetics; Polymorphism, Restriction Fragment Length - genetics; Promoter Regions, Genetic - genetics; schizophrenia; Schizophrenia - diagnosis; Schizophrenia - genetics; Turkey; Young Adult
• ISSN: 1562-2975; 1814-1412
• DOI: 10.1080/15622970802626580

Schizophrenia is one of the most severe psychiatric disorders, with a worldwide incidence of 1%. Immunological abnormalities have been found to be associated with schizophrenia for decades. Cytokines are key proteins involved in the immune system activation. Interleukin-10 (IL-10), an important immunoregulatory cytokine, is located on chromosome 1q31-32, a region previously reported to be linked to schizophrenia in genetic studies. In the present study it was aimed to examine the IL-10 gene promoter region's polymorphic variants in patients with schizophrenia in a population of the Elazig Region of East Anatolia, Turkey. Polymorphisms at position −1082, −819 and−592 in the IL-10 promoter region were determined in 171 Turkish patients who were diagnosed with schizophrenia, based on the DSM-IV, and 168 healthy controls, by polymerase chain reaction (PCR)-restriction fragment length polymorphism (RFLP). We analyzed allele, genotype, and haplotype distributions using a case-control association study. Genotyping was performed by RFLP. Statistically significant differences were observed in both allelic and genotypic frequencies of the−592A/C polymorphism (Allele, P=0.034, OR = 1.26, 95% CI 1.02-1.56; Genotype, P=0.048), while the other two polymorphisms in distribution of the alleles and genotypes in patients with schizophrenia were not significantly different from those of controls (P>0.05). Our results show a significant increase of GTA homozygotes (the high IL-10-producing haplotype) in schizophrenic patients compared to control subjects (P=0.0001). These data suggest that the IL-10 gene promoter polymorphism may be one of the susceptibility factors to develop schizophrenia in the Turkish population, and apparently in all humans.