Polymorphisms in Turkish population

Department of Medical Biology, Faculty of Medicine, Ankara University, Ankara, Turkey guvemg@yahoo.com.

Human P-glycoprotein (P-gp) is encoded by the MDR1 gene, which is located on chromosomal region 7q21 and consists of 28 exons. To date, over 50 single nucleotide polymorphisms (SNPs) have been reported for the MDR1 gene. The effect of these polymorphisms on P-gp function or their clinical impact is in most cases unknown, but some of the SNPs are known to be of functional relevance and can also alter the pharmacokinetics of substrate drugs. The aim of the current study was to analyze for the first time an existing silent MDR1 C1236T (Gly412Gly) polymorphism in a Turkish population. The genotype frequencies of C1236T SNP in a Turkish population were also compared with those in other populations. One hundred unrelated healthy subjects (48 females, 52 males) were included in this study and all them were of Turkish ethnicity. The genotyping of the C1236T SNP was performed by the polymerase chain reaction (PCR)-restriction fragment length polymorphism (RFLP) method. The frequencies of the wild-type C and mutant T alleles were 45.5 and 54.5%, respectively. The distribution of C1236T genotype frequencies in our study group was found to be similar to that in Czech, Polish, Portuguese, Russian, Malay, and Japanese populations and different from that in French, German, Chinese, and Indian populations. The distributions of CC, CT, and TT genotypes were 20.0, 51.0, and 29.0%, respectively. Our study provides a framework for future studies concerning the role of polymorphic variants of MDR1 gene in the genesis of various diseases or in designing future pharmacogenetic and pharmacokinetic studies conducted with P-gp substrates in the Turkish population.

Department of Endocrinology, Gazi University Faculty of Medicine, Ankara, Turkey. drhdemirci@hotmail.com

The association of the gene encoding calpain 10 with type 2 diabetes mellitus (T2DM) has been reported. In this study we aimed to evaluate the association of SNP-19,-44, and -63 polymorphisms of calpain 10 with type 2 diabetes and diabetic-related conditions, such as diabetic retinopathy, nephropathy, and neuropathy in a Turkish population. The study group included 202 patients (133 female and 69 male) with T2DM, while the control group included 80 nondiabetic people (44 female and 36 male). Genotyping was done by the polymerase chain reaction and restriction fragment length polymorphism method. Calpain 10 SNP-44 TC genotype was found to be significantly frequent in type 2 diabetic patients with respect to the control group (p < 0.01). Body mass index (BMI) was found to be significantly high in TC genotype with type 2 diabetic patients (p < 0.05). SNP-44 T allele frequency was found to be lower in type 2 diabetic patients compared with the controls (p < 0.01). We conclude that the calpain 10 SNP-44 gene polymorphism may be accepted as a risk factor in the development of T2DM and elevated BMI in type 2 diabetic patients in a Turkish population.