Polymorphisms in Turkish population

Author(s): Ozbey U (Ozbey, Ulku)2, Tug E (Tug, Esra)1, Namli M (Namli, Mustafa)3
Source: WORLD JOURNAL OF BIOLOGICAL PSYCHIATRY Volume: 10 Issue: 5 Pages: 461-468 Published: 2009

Abstract: 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.
Document Type: Article
Language: English
Author Keywords: Biological psychiatry; cytokines; genetics; polymorphism; schizophrenia
KeyWords Plus: ASSOCIATION; HAPLOTYPES; POPULATION; LINKAGE
Reprint Address: Tug, E (reprint author), Abant Izzet Baysal Univ, Izzet Baysal Med Sch, Dept Med Genet, TR-14280 Bolu, Turkey
Addresses:
1. Abant Izzet Baysal Univ, Izzet Baysal Med Sch, Dept Med Genet, TR-14280 Bolu, Turkey
2. Firat Univ, Fac Med, Dept Med Biol & Genet, TR-23169 Elazig, Turkey
3. Hosp Psychiat, Elazig, Turkey
E-mail Addresses: esratug@hotmail.com

Int J Toxicol. 2006 Sep-Oct;25(5):419-22.

Kocabaş NA, Karahalil B.

Department of Toxicology, Gazi University, Faculty of Pharmacy, Ankara, Turkey.

Humans are routinely exposed to mutagenic and carcinogenic chemicals. These chemicals can form DNA adducts in vivo and thus lead to DNA damage. The integrity of most of the so-damaged DNAs is typically restored as a consequence of the action of certain DNA-repairing enzymes. In several DNA repair genes, polymorphisms may result in reduced repair capacity, which has been implicated as a risk factor for various types of cancer. XRCC1 is a base-excision repair protein that plays a central role in the repair of DNA base damage and strand breaks. Amongst the known genetic polymorphisms of the DNA-repair genes, X-ray repair cross-complementing groups 1 and 3 (XRCC1 and XRCC3) have been studied most commonly. Inconsistent results have been reported regarding the associations between the Arg399Gln (exon 10) polymorphism of XRCC1 and either functional significance or the risk of tobacco-associated cancers. The Gln allele of this polymorphism was associated with higher levels of DNA adducts. Therefore we genotyped one of the polymorphism of XRCC1, Gln allele. The frequency of the polymorphic alleles varies among populations, suggesting an ethnic distribution of genotypes. There has been no information on interindividual variability of Arg399Gln genotype in the Turkish population. Due to the association between the Arg399Gln polymorphism of XRCC1 and the risk of tobacco-associated cancers, we preferred to evaluate the allelic frequencies of Arg399Gln genotype than the other polymorphisms in XRCC1 gene in healthy Turkish population by polymerase chain reaction-restriction fragment polymorphism (PCR-RFLP) analysis to enable to show interindividual differences and compare to other populations.