Molecular and Clinical Implications of Variant Repeats in Myotonic Dystrophy Type 1

Myotonic dystrophy type 1 (DM1) is one of the most variable monogenic diseases at phenotypic, genetic, and epigenetic level. The disease is multi-systemic with the age at onset ranging from birth to late age. The underlying mutation is an unstable expansion of CTG repeats in the DMPK gene, varying in size from 50 to >1000 repeats. Generally, large expansions are associated with an earlier age at onset. Additionally, the most severe, congenital DM1 form is typically associated with local DNA methylation. Genetic variability of DM1 mutation is further increased by its structural variations due to presence of other repeats (e.g., CCG, CTC, CAG). These variant repeats or repeat interruptions seem to confer an additional level of epigenetic variability since local DNA methylation is frequently associated with variant CCG repeats independently of the expansion size. The effect of repeat interruptions on DM1 molecular pathogenesis is not investigated enough. Studies on patients indicate their stabilizing effect on DMPK expansions because no congenital cases were described in patients with repeat interruptions, and the age at onset is frequently later than expected. Here, we review the clinical relevance of repeat interruptions in DM1 and genetic and epigenetic characteristics of interrupted DMPK expansions based on patient studies

Analysis of association of potentially functional genetic variants within genes encoding miR-34b/c, miR-378 and miR-143/145 with prostate cancer in Serbian population

MiRNA-associated genetic variants occurring in regulatory regions can affect the efficiency of transcription and potentially modify pri-miRNA or pre-miRNA processing. Since miRNA-based mechanisms are shown to be involved in the pathogenesis of prostate cancer (PCa), the aim of the present study was to evaluate the effect of rs4938723, rs1076064 and rs4705343 occurring in regulatory regions of miR-34b/c, miR-143/145 and miR-378, respectively, on PCa risk and progression in Serbian popul ation. We examined a total of 1060 subjects, of which 350 were patients with PCa, 354 were patients with benign prostatic hyperplasia (BPH), while 356 healthy volunteers were included in the control group. Genotyping of rs4938723, rs1076064 and rs4705343 was performed by using Taqman® SNP Genotyping Assays. Allele C of rs4705342 was found to increase the risk of PCa (P=0.031 for codominant model, P=0.0088 for recessive model). Rs1076064 minor allele G was found to associate with serum PSA score, as well as with PCa T category and disease aggressiveness. For rs4938723 minor allele C was shown to be associated with the lower PCa T category (Pdom=0.0046; OR=0.36, 95 % CI 0.17-0.76) in T2 vs. T1 comparison. Rs4705342 was identified as PCa susceptibility variant in Serbian population, while for rs1076064 and rs4938723 association with PCa progression parameters was found

Superoxide Anion Radical Production in the Tardigrade Paramacrobiotus richtersi, the First Electron Paramagnetic Resonance Spin-Trapping Study

Anhydrobiosis is an adaptive strategy that allows withstanding almost complete body water loss. It has been developed independently by many organisms belonging to different evolutionary lines, including tardigrades. The loss of water during anhydrobiotic processes leads to oxidative stress. To date, the metabolism of free radicals in tardigrades remained unclear. We present a method for in vivo monitoring of free radical production in tardigrades, based on electron paramagnetic resonance and spin-trap DEPMPO, which provides simultaneous identification of various spin adducts (i.e., different types of free radicals). The spin trap can be easily absorbed in animals, and tardigrades stay alive during the measurements and during 24-h monitoring after the treatment. The results show that hydrated specimens of the tardigrade Paramacrobiotus richtersi produce the pure superoxide anion radical ((•)O2(-)). This is an unexpected result, as all previously examined animals and plants produce both superoxide anion radical and hydroxyl radical ((•)OH) or exclusively hydroxyl radical

Fuchs Endothelial Corneal Dystrophy in Patients With Myotonic Dystrophy

PURPOSE: To report four cases of Fuchs endothelial corneal dystrophy (FECD) in patients with an established diagnosis of myotonic dystrophy (DM) and suggest a mechanism for their association based on the known molecular genetics and potential pathophysiological parallels of DM and FECD. METHODS: We reviewed all available medical records and pathology slides for the four reported cases from the Department of Ophthalmology at Oregon Health & Science University’s Casey Eye Institute as well as Devers Eye Institute at Legacy Good Samaritan Medical Center in Portland, OR. RESULTS: Four patients were found to have myotonic dystrophy as well as bilateral corneal guttae, consistent with the diagnosis of FECD. All of the identified patients were female and between the ages of 34–63, and two of the patients were related (mother and daughter). The corneal specimens from two of the four patients who had undergone corneal transplant were pathologically confirmed to be consistent with FECD. CONCLUSION: To our knowledge, FECD has not been previously reported in association with DM. Because both diseases are somewhat prevalent in the U.S., it is possible that their coexistence is merely a coincidence in these patients. However, recent studies into the pathogenesis of each disease have shown more parallels between FECD and DM, suggesting the possibility of a non-coincidental association. Potential mutual pathogenic mechanisms may involve altered protein expression causing deregulation of ion homeostasis, an unstable intronic trinucleotide repeat expansion, or activation of the unfolded protein response and oxidative stress pathways

Metabolic impairments in patients with myotonic dystrophy type 2

Objectives: metabolic syndrome (MetS) increases risk of cardiovascular diseases and diabetes mellitus type 2. Aim of this study was to investigate frequency and features of MetS in a large cohort of patients with DM2. Materials & methods: this cross-sectional study included 47 DM2 patients. Patients were matched with 94 healthy controls (HCs) for gender and age. MetS was diagnosed according to the new worldwide consensus criteria from 2009. Results: mean age of DM2 patients was 52 ± 11 years, 15 (32%) were males, and mean disease duration was 15 ± 14 years. MetS was present in 53% of DM2 patients and 46% of HCs (p > 0.05). All components of the MetS appeared with the similar frequency in DM2 and HCs, respectively: hypertension 64 vs 52%, central obesity 62 vs 74%, hypertriglyceridemia 49 vs 39%, hyperglycemia 42 vs 33% and low HDL cholesterol 30 vs 42% (p > 0.05). DM2 patients were more commonly on lipid lowering therapy compared to HCs (12 vs 3%, p = 0.05). Fifteen (32%) patients with DM2 and only one (1%) subject from control group had diabetes mellitus (p 0.05). Conclusions: more than half of DM2 subjects met the criteria for the MetS. We suppose that treatment of metabolic disturbances may reduce cardiovascular complications and improve quality of life in patients with DM2, which is progressive and still incurable disorder

C8 ANALYSIS OF TWO SINGLE NUCLEOTIDE POLYMORPHISMS AT LOCUS 17Q12 ASSOCIATED WITH PROSTATE CANCER IN SERBIAN POPULATION

Introduction & Objectives: Prostate cancer (PC) is the most prevalent type of cancer in males, comprising about 29% of all malignant tumors. Association with race, family and specific gene variants suggests strong role of genetics in prostate cancer etiology. Two nucleotide polymorphisms (SNPs) at 17q12 locus have been associated with the risk of developing prostate cancer in several previous genome-wide association studies. The correlation between the prostate cancer and rs7501939 and rs3760511 has already been confirmed in other populations, the goal of this study is to test whether it applies to Serbian population. material & methods: Analyses were done on 150 peripheral blood samples, taken from 100 patients diagnosed with prostate cancer whose prostate-specific antigen (PSA) serum levels and Gleason score were available and from 50 patients diagnosed with benign prostatic hyperplasia (BPH) , while the controls were 100 DNA swab samples taken from healthy individuals. The work proceeded through PCR amplification of two regions surrounding SNPs, restriction fragment length polymorphism (RFLP) analysis and random capillary gel electrophoresis of PCR samples from each SNP group as a control of RFLP analysis. The differences in genotype frequencies between case and control subjects were tested using a chisquare test with 1 degree of freedom. Results: The Chi-square test was used to determine if there is a statistical correlation between the SNP and PC and BPH. In the case of rs3760511 there was no correlation between the controls and the PC, but at the same time, there was a major statistical correlation between the BPH and PC samples, and also between BPH and the controls. The rs7501939 also showed no statistical correlation between the controls and PC samples, but showed correlation between controls and BPH as well as between BPH and PC samples. Also, there is no statistical correlation between the Gleason score, PSA levels and the SNP’s studied. Conclusions: The two SNP’s studied are not correlated to the PC in Serbian population.Poster Session 1 PROSTATE CANCER I Friday, 28 Octobe

Joint effect of ADARB1 gene, HTR2C gene and stressful life events on suicide attempt risk in patients with major psychiatric disorders

Objectives. Adenosine to inosine RNA editing, serotonin 2C receptor (HTR2C), and stressful life events (SLEs) have all been implicated in suicidal behaviour. We examined the main and moderating effects of RNA editing (ADAR, ADARB1) and HTR2C genes, childhood trauma (CT), recent SLEs and psychiatric disorders as contributors to suicide attempt (SA) vulnerability. Methods. Study included 165 suicide attempters and 188 suicide non-attempters, all diagnosed with one of major psychiatric disorders. CT and recent SLEs were assessed using Early Trauma Inventory-Self Report and List of Threatening Experiences Questionnaire, respectively. Selected ADAR and ADARB1 tag-variants, and HTR2C rs6318 were pre-screened for association with SA, while generalized linear models and backward selection were applied to identify individual and interacting SA risk factors. Results. ADARB1 rs9983925 and rs4819035 and HTR2C rs6318 were associated with SA. The best minimal model found emotional abuse, recent SLEs, rs9983925 and rs6318 as independent SA risk factors, and general traumas as a factor moderating the effect of psychiatric disorders and emotional abuse. Conclusions. SA vulnerability in psychiatric patients is related to the joint effect of ADARB1 and HTR2C variants, the existing mood disorder and the cumulative exposures to a various childhood and recent stressful experiences.Ministry of Education, Science and Technological Development, Republic of Serbia {[}173016