Original ©2013 Dustri-Verlag Dr. K. Feistle ISSN 0301-0430 DOI 10.5414/CN107863 e-pub: March 5, 2013 Received August 14, 2012; accepted in revised form October 19, 2012 Correspondence to Sultan Ozkurt, MD Division of Nephrology, Faculty of Medicine, Eskisehir Osmangazi University, Eskisehir, Turkey dr.s.guvenir@hotmail.com Key words nephrotic syndrome – thromboembolic complications – heredi- tary thrombophilia Assessment of genetic risk factors for thromboembolic complications in adults with idiopathic nephrotic syndrome Melisa Sahin, Sultan Ozkurt, Nevbahar Akcar Degirmenci, Ahmet Musmul, Gokhan Temiz and Mehmet Soydan Division of Nephrology, Faculty of Medicine, Eskisehir Osmangazi University, Eskisehir, Turkey Abstract. Aims: Nephrotic syndrome (NS) may occur with acquired hypercoagula- bility, however, the fact that it is accompanied by an underlying hereditary thrombophilia, especially combined hereditary thrombo- philia, would lead to thrombotic events. In this study, we aimed to evaluate the contribu- tion of genetic thrombophilia to development of thrombotic events in adult patients with NS. Material and methods: Factor V Leiden (FVL), prothrombin, and methylenetetrahy- drofolate reductase (MTHFR) gene mutation were studied in 51 newly diagnosed idiopathic NS patients and age- and gender-matched 20 healthy control subjects included in the study. Renal vein Doppler ultrasound was conducted in order to investigate the prevalence of sub- clinical renal vein thrombosis. Results: Of 51 patients, 6 (11.8%) were established to have thromboembolic (TE) complications at the time of diagnosis (4 symptomatic, 2 subclini- cal), and no recurring thrombotic episode was observed. Genetic mutation was established in all patients that were found to have TE com- plications. Acquired hypercoagulability fac- tors were similar in patients without and with TE complication. Conclusions: The coexis- tence of inherited thrombophilia in NS may facilitate thromboembolic complications. If the cause of thrombosis cannot be explained by the usual factors attributed to the occur- rence of thrombosis in NS, screening for the other factors, such as FVL, MTHFR, and pro- thrombin gene mutation, may be benefcial. Introduction The hemostatic system is activated in ne- phrotic syndrome, with an increased tendency toward thrombosis [1]. Abnormalities of the coagulation system result from a complex in- terplay between increased hepatic synthesis and intravascular consumption of coagulation factors and accelerated thrombin generation [1, 2]. The acquired hypercoagulability associated with nephrotic syndrome could, however, coin- cide with underlying inherited thrombophilia, thereby resulting in a thrombotic event [3]. In literature, there exists information as to the fact that underlying genetic thrombophilia cause earlier-presenting, life-threatening thrombotic complications in the presence of such a facili- tating factor as nephrotic syndrome [4, 5]. In adult nephrotic syndrome patients, however, the genetic aspect of thrombotic events has not been studied much and was reported more like case studies [6, 7]. Resistance to activated pro- tein C, caused by a single-point mutation in the Factor V gene (Factor V Leiden), has been re- ported as the most common hereditary cause of venous thrombosis [8]. This mutation has been found in 30 – 60% of cases of familial throm- bophilia and in 3 – 7% healthy people in two White populations [9]. Among individuals with inherited hyperhomocysteinemia, those homo- zygous for methylenetetrahydrofolate reduc- tase have elevated plasma homocysteine levels and an important genetic risk factor for vascu- lar disease [10]. The transition 20210G →A in the 3’ untranslated region of the prothrombin gene was associated with higher prothrombin levels and with a threefold greater risk of ve- nous thrombosis [11]. In this study, we aimed to evaluate the contribution of genetic risk fac- tors frequently observed for vascular thrombo- sis in patients with adult nephrotic syndrome to the development of thrombosis. Patients and methods The study was prospectively conducted between January 2010 and December 2011 at the Nephrology Clinic of the Medical Clinical Nephrology, Vol. 79 – No. 6/2013 (454-462)