Yazan: admin Tarih: May 19th, 2011 | Kategori::
Gene polymorphisms
Mol Med Report. 2010 Jul-Aug;3(4):723-7. doi: 10.3892/mmr_00000324.
Microsomal epoxide hydrolase polymorphisms.
Pinarbasi H, Silig Y, Pinarbasi E.
Source
Department of Biochemistry, Faculty of Medicine, Cumhuriyet University, 58140 Sivas, Turkey. hpinar2658@gmail.com.
Abstract
Microsomal epoxide hydrolase plays a dual role in the activation and detoxification of carcinogenic compounds. Two polymorphic sites have been described in exons 3 and 4 of the microsomal epoxide hydrolase gene that change tyrosine residue 113 to histidine (Tyr113His) and histidine 139 to arginine (His139Arg), respectively. The exon 3 polymorphism reduces enzyme activity by approximately 50%, whereas the exon 4 polymorphism causes a 25% increase in activity. In the present study, the distribution of these polymorphisms in a Turkish population including 625 unrelated healthy individuals was examined using a PCR-RFLP method. The observed genotype frequencies of microsomal epoxide hydrolase exon 3 were 54, 38 and 8% for Tyr113Tyr, Tyr113His and His113His, respectively. Exon 4 genotype frequencies were found to be 69, 29 and 2% for His139His, His139Arg and Arg139Arg, respectively.
Yazan: admin Tarih: Kas 30th, 2010 | Kategori::
PON1
Biochem Genet. 2010 Sep 7.
Ergun MA, Yurtcu E, Demirci H, Ilhan MN, Barkar V, Yetkin I, Menevse A.
Department of Medical Genetics, Gazi University Faculty of Medicine, Besevler, 06500, Ankara, Turkey, ergun@tr.net.
Abstract
Diabetes mellitus is a multifactorial metabolic disease, caused by the complete or relative absence of insulin hormone, which results in the deterioration of carbohydrate, protein, and lipid metabolism. The PON1 55 and 192 polymorphisms have been reported to be associated with type 2 diabetes and its complications. In this study, the involvement of the PON1 55 and 192 polymorphisms and paraoxonase enzyme activity in diabetic complications was assessed. The MM and QQ genotypes were the most frequent in complications of type 2 diabetes in both of the polymorphisms. PON enzyme activity was lower in the type 2 diabetes group with respect to the control group. Regarding both genotypes and enzyme activity, correlations were found between the PON1 55 and 192 genotypes and diabetic complications. This study thus helps to outline a genotype-phenotype relation for the PON1 gene in a Turkish population.
Yazan: admin Tarih: Ağu 3rd, 2008 | Kategori::
Leukemia(Kan Kanseri)
Am J Hematol. 2007 Oct;82(10):906-10.
Biochemistry Graduate Programme and Department of Biological Sciences, Middle East Technical University, 06531 Ankara, Turkey.
6-Mercaptopurine (6MP) is an essential anticancer drug used in the treatment of childhood acute lymphoblastic leukemia (ALL). Thiopurine methyltransferase (TPMT) polymorphisms are the major determinants of interindividual differences in the severe toxicity or efficacy of 6MP. Four variant alleles, TPMT*2, TPMT*3A, TPMT*3B, and TPMT*3C, are responsible over the 80% of low or undetectable enzyme activity. The frequencies of these variants were investigated among 106 children with ALL in Turkish population. TPMT*3A and TPMT*3C were the only deficiency alleles detected in Turkish population with an allele frequency of 0.9% for both. While *3C allele frequency in Turkish population was found to be very similar to Asian and other Caucasian populations, *3A allele frequency was significantly (P < 0.05) lower. So far, studies showed that the genetic polymorphisms of other drug metabolizing enzymes like CYP2E1, CYP1A1, GSTM1/ T1 in Turkish population were similar to Caucasian populations. However, we found that the distribution of TPMT polymorphisms in Turkish population was significantly lower than those in other Caucasians like British, French, and Italian whereas the distributions of TPMT variants were found to be very similar to Kazak population which is also Caucasian in ethnic origin. In this study, the clinical histories of the patients in the sample population were also examined, retrospectively. The patients with heterozygous or homozygous mutant genotypes had developed severe neutropenia and infection during 6MP therapy. The study provides the first data on the frequency of common TPMT variants in the Turkish population, based on analysis of pediatric patients with ALL.
