Polymorphisms in Turkish population

Faculty of Medicine, Department of Medical Biology, Harran University, Sanliurfa, Turkey.

Type 2 diabetes mellitus (T2DM) is by far the most common type of diabetes and is characterized by insulin resistance and altered insulin secretion. Some genes, such as the vitamin D receptor gene (VDR, NM_001017535; GI: 7421), involved in its metabolic pathway have been regarded as good candidates for T2DM. In this study, we investigated whether there was an association of VDR: g.59979G>T or c.1025-49G>T (ApaIG>T) and g.60058T>C or c.1056T>C (TaqIT>C) polymorphisms in the 3′ untranslated region of VDR with T2DM in a Turkish population. We collected blood samples from 241 individuals (72 patients with T2DM and 169 healthy individuals), and their DNA was isolated. Polymorphisms of the VDR were analyzed by DNA amplification with polymerase chain reaction and endonuclease digestion with ApaI and TaqI. Body mass index was higher in T2DM patients than in control individuals. However, the frequency of g.59979TT genotype in T2DM patients was not significantly increased compared to healthy subjects (37.5% vs. 36.1%, respectively). Although the VDR g.60058CC genotype in T2DM patients (19.4%) was higher than that in healthy individuals (11.2%), there was no significant difference. In the same way, there was no difference between the groups in allele frequencies. In conclusion, our study did not provide evidence for the association of two examined VDR polymorphisms with T2DM in a Turkish population.

J Mol Med. 2006 Dec;84(12):1015-22. Epub 2006 Oct 13.

Treiber M, Schulz HU, Landt O, Drenth JP, Castellani C, Real FX, Akar N, Ammann RW, Bargetzi M, Bhatia E, Demaine AG, Battagia C, Kingsnorth A, O’Reilly D, Truninger K, Koudova M, Spicak J, Cerny M, Menzel HJ, Moral P, Pignatti PF, Romanelli MG, Rickards O, De Stefano GF, Zarnescu NO, Choudhuri G, Sikora SS, Jansen JB, Weiss FU, Pietschmann M, Teich N, Gress TM, Ockenga J, Schmidt H, Kage A, Halangk J, Rosendahl J, Groneberg DA, Nickel R, Witt H.

Department of Hepatology and Gastroenterology, Charité, Campus Virchow-Klinikum, Universitätsmedizin Berlin, Berlin, Germany.

Keratin 8 (KRT8) is one of the major intermediate filament proteins expressed in single-layered epithelia of the gastrointestinal tract. Transgenic mice over-expressing human KRT8 display pancreatic mononuclear infiltration, interstitial fibrosis and dysplasia of acinar cells resulting in exocrine pancreatic insufficiency. These experimental data are in accordance with a recent report describing an association between KRT8 variations and chronic pancreatitis. This prompted us to investigate KRT8 polymorphisms in patients with pancreatic disorders. The KRT8 Y54H and G62C polymorphisms were assessed in a cohort of patients with acute and chronic pancreatitis of various aetiologies or pancreatic cancer originating from Austria (n=16), the Czech Republic (n=90), Germany (n=1698), Great Britain (n=36), India (n=60), Italy (n=143), the Netherlands (n=128), Romania (n=3), Spain (n=133), and Switzerland (n=129). We also studied 4,234 control subjects from these countries and 1,492 control subjects originating from Benin, Cameroon, Ethiopia, Ecuador, and Turkey. Polymorphisms were analysed by melting curve analysis with fluorescence resonance energy transfer probes. The frequency of G62C did not differ between patients with acute or chronic pancreatitis, pancreatic adenocarcinoma and control individuals. The frequency of G62C varied in European populations from 0.4 to 3.8%, showing a northwest to southeast decline. The Y54H alteration was not detected in any of the 2,436 patients. Only 3/4,580 (0.07%) European, Turkish and Indian control subjects were heterozygous for Y54H in contrast to 34/951 (3.6%) control subjects of African descent. Our data suggest that the KRT8 alterations, Y54H and G62C, do not predispose patients to the development of pancreatitis or pancreatic cancer.