Society of Diabetic Nephropathy Prevention Journal of Nephropathology 2251-8363 7 2 2018 04 01 Genetic variations of complement factor H and C3 in patients with thrombotic thrombocytopenic purpura (TTP) in northwest of Iran 74 78 10.15171/jnp.2018.18 EN Sepideh Zununi Vahed Bahram Niknafs Mahmoud Shekari Khaniani Mohammadreza Ardalan Journal Article 10.15171/jnp.2018.18 2017 09 03 2017 11 14 Background: Thrombotic thrombocytopenic purpura (TTP) is a common form of thrombotic microangiopathy. These patients have renal insufficiency as well as thrombocytopenia and microangiopathic hemolysis. Objectives: The present study was aimed to assess if TTP patients with renal failure have prompting polymorphisms in the complement system genes as seen in patients with the atypical hemolytic uremic syndrome (aHUS). Patients and Methods: Twenty TTP patients and 30 healthy individuals were included. Two single-nucleotide polymorphisms rs3753394 and rs2230199 respectively in the complement factor H (CFH) and complement component 3 (C3) genes were determined using the PCRrestriction fragment length polymorphism (RFLP) method. To evaluate the power of the associations between the polymorphisms and TTP development, odds ratios (ORs) and 95% confidence intervals (CIs) were employed. Results: In rs2230199 polymorphism, the frequency of the C and G alleles and genotype were not significantly different in case and control groups. Moreover, the frequency of T allele and CC, CT, and TT genotypes of the rs3753394 polymorphism in TTP patients were not significantly different from those in the controls, the OR of 0.77 [CI: 0.33 to 1.79] and 0.76 [CI: 0.24 to 2.38], respectively (P > 0.05). Conclusions: Based on our results, there was no significant association between the incidence of TTP and polymorphisms of the CFH and C3 genes, neither at the allele nor at the genotypic levels (P > 0.05). This finding can be affected by the limited sample size or the genetic context of the studied population.