Nejat Akar

Behçet's: A Disease or a Syndrome? Answer from an Expression Profiling Study

Behçet’s disease (BD) is a chronic, relapsing, multisystemic inflammatory disorder with unanswered questions regarding its etiology/pathogenesis and classification. Distinct manifestation based subsets, pronounced geographical variations in expression, and discrepant immunological abnormalities raised the question whether Behçet’s is “a disease or a syndrome”. To answer the preceding question we aimed to display and compare the molecular mechanisms underlying distinct subsets of BD. For this purpose, the expression data of the gene expression profiling and association study on BD by Xavier et al (2013) was retrieved from GEO database and reanalysed by gene expression data analysis/visualization and bioinformatics enrichment tools. There were 15 BD patients (B) and 14 controls (C). Three subsets of BD patients were generated: MB (isolated mucocutaneous manifestations, n = 7), OB (ocular involvement, n = 4), and VB (large vein thrombosis, n = 4). Class comparison analyses yielded the following numbers of differentially expressed genes (DEGs); B vs C: 4, MB vs C: 5, OB vs C: 151, VB vs C: 274, MB vs OB: 215, MB vs VB: 760, OB vs VB: 984. Venn diagram analysis showed that there were no common DEGs in the intersection “MB vs C” ∩ “OB vs C” ∩ “VB vs C”. Cluster analyses successfully clustered distinct expressions of BD. During gene ontology term enrichment analyses, categories with relevance to IL-8 production (MB vs C) and immune response to microorganisms (OB vs C) were differentially enriched. Distinct subsets of BD display distinct expression profiles and different disease associated pathways. Based on these clear discrepancies, the designation as “Behçet’s syndrome” (BS) should be encouraged and future research should take into consideration the immunogenetic heterogeneity of BS subsets. Four gene groups, namely, negative regulators of inflammation (CD69, CLEC12A, CLEC12B, TNFAIP3), neutrophil granule proteins (LTF, OLFM4, AZU1, MMP8, DEFA4, CAMP), antigen processing and presentation proteins (CTSS, ERAP1), and regulators of immune response (LGALS2, BCL10, ITCH, CEACAM8, CD36, IL8, CCL4, EREG, NFKBIZ, CCR2, CD180, KLRC4, NFAT5) appear to be instrumental in BS immunopathogenesis.

Novel mutations of integrin αIIb and β3 genes in Turkish children with Glanzmann’s thrombasthenia

Abstract Glanzmann’s thrombasthenia (GT) is an inherited disorder of platelet aggregation, characterized by qualitative and quantitative defect on platelet αIIbβ3 integrin (GpIIb/IIIa), resulting in lifelong bleeding tendency due to defective platelet plug formation. The αIIb gene (ITGA2B) and β3 gene (ITGB3) are closely located at chromosome 17q21.31-32. ITGA2B consist of 30 exons and encoding α chain, whereas ITGB3 has 15 exons and encoding β chain. Until now, according to the Human Gene Mutation Database (HGMD), 138 mutations at ITGA2B gene and 101 mutations at ITGB3 gene have been identified. We aimed to determine whether there was any mutation in the ITGA2B and ITGB3 genes, and a correlation between clinical phenotype and genotype in Turkish GT patients. We examined 20 patients with GT followed at the Department of Pediatric Hematology, Meram Faculty of Medicine, for Clinical and Laboratory Findings and Molecular Genetic Analysis. Peripheral blood was collected from patients, and a written informed consent for genetic analysis was obtained from parents. DNA was isolated from by proteinase K and phenol/chloroform extraction. ITGA2B and ITGB3 genes were screened by polymerase chain reaction. There were 12 females and 8 males with a median age of 15.25 years. Major clinical presentations of these patients were mucocutaneous bleedings. The most common bleeding type was epistaxis (85%). Life-threatening bleedings were seen in five patients. Seven (35%) patients showed various mutations in the ITGA2B or ITGB3 genes. We detected four novel mutations in three different regions and two mutations defined previously within the ITGA2B gene. These changes are at exon 4; c.570 T > G alteration, at exon 13 c.1277 T > A, c.1291 T > G alterations, at exon 19 c.1921A > G alterations. And from the start point of exon 14, behind 107 bases, we detected a heterozygous alteration at Thymine to Guanine. According to PolyPhen Database Program and NCBI Multiple Alignment Tool Database, four transitions are conserved at evolutionary process, so we can say that these transitions are novel mutations. c. 468T > G alteration at exon 4 and c. 1378 T > A alteration at exon 13 were reported to HGMD previously. Screening the exons of the ITGB3 gene from the same patient groups, we reported a novel missense mutation at exon 5, at nucleotide 680. No correlation was found between clinical phenotype and genotype. These mutations were described for the first time in Turkish population, and all novel mutations are not defined previously. Furthermore, collaborative studies are needed for the population point of view.

The Role of Factor V Leiden in Adult Patients With Venous Thromboembolism: A Meta-Analysis of Published Studies From Turkey

Factor V Leiden (FVL) is the most common inherited risk factor for venous thromboembolism (VTE). The frequency of FVL in patients with VTE has been reported from different parts of Turkey. A meta-analysis was performed to estimate the risk of VTE associated with FVL in Turkish population. Published studies were retrieved from Pubmed and Science Citation Index/Expanded. We selected studies comparing the prevalence of FVL in patients with VTE with controls. The analysis was performed by the software comprehensive meta-analysis. The analysis consisted of 10 studies including 1202 patients with VTE and 1283 controls. The pooled frequency of FVL was significantly higher in patients with VTE (22.8%) than controls (7.6%). The pooled odds ratio (OR) was 3.4 (95% confidence interval [CI], 2.6-4.5). The study showed homogeneity (Q value, 9.955). No publication bias was observed in any comparison model. Our meta-analysis showed an association of FVL with VTE in Turkey.

Factor V Leiden and Natural Selection

Factor V Leiden ([FVL] 1691G-A) is a thrombophilic singlepoint mutation (G1691A), leading to an amino acid substitution of Arg with Gln that causes activated protein C (APC) resistance, thus, yielding to a hypercoagulation disorder. The mutation shows an uneven geographic distribution, ranging from nonexistence in natives of Africa, America, Asia, and Australia, to high existence reaching at 15% in some areas of Europe. High prevalence of the mutation among all whites makes it plausible to ask whether FVL had caused selective advantages during evolution, some of which are assumed to be the reduction in the risk of hemorrhage after delivery and also for fighter ancestors living in a period when no satisfactory medical care was offered. It should also be noted that reduction in the mortality rate might be related to severe sepsis. The disadvantageous impact of the mutation, resulting in a higher risk of thrombosis, might not have been as damaging because the risk factors associated with the lifestyle such as arteriosclerosis were rare. A supporting data were obtained from a contemporary study in which the participants were centenarians, suggesting that FVL does not contradict extreme longevity and successful ageing. There exists limited information about why some mutations causing susceptibility to diseases are present in a high frequency rather than not being eliminated by natural selection. Most probably, the answer lies in the survival advantage caused by the mutation. Even a small increase in the frequency of FVL for 1 generation would have yielded a significant difference through hundreds of generations. Turkey, lying between 2 continents, Europe and Asia, connecting East and West, played a major role in the world history. Turkish population seems to be a very good resource to study the possible selective disadvantages of FVL with its significantly high frequency. Furthermore, historically Turkish population experienced neither war nor famine during the last 85 years, with decreasing newborn and childhood deaths along the last century. Review on the distribution of FVL in Turkish population revealed FVL frequency as 7.9% among normal healthy Turkish adults, whereas it was 12% among newborns. The difference between adults and newborns needed further attention. There should be a reason for the difference between newborns and adults. This review was undertaken in order to clarify the difference. A marked difference between adult and newborn frequency may have importance (8.0% vs 11.5%; Table 1). This calls to mind the question, ‘‘Did some of the infants with FVL mutation die of clinical conditions related to thromboembolism before reaching adult age and without receiving a specific diagnosis?’’ This may explain the difference between the frequencies in newborns and adults. The difference between the 2 groups was statistically significant (P1⁄4 .015). If this hypothesis is verified by other studies, it will be a very important finding from an evolutionary point of view. The data revealed us to study the question whether carrying FVL affects the morbidity of children with thrombosis. We compared the effect of FVL in children with thrombosis with and without FVL. Kaplan-Meier analysis revealed that in the control group the 5-year survival rate was 76%; in the FVL carrier group, it was 56%. In the control group, average age of survival was 9.33 (8.79-9.88) and it was 7.13 (6.56-7.71) in the FVL carrier group. Log-rank test was statistically significant (P = 0.00). Further carrying FVL increases the risk of pediatric stroke significantly. Another interesting point was that FVL increased among the elderly (older than 70 years) to 11.5%. The difference between elderly group and the other 2 groups is insignificant, respectively (P1⁄4 .8 and P1⁄4 .13). Our data are similar to the previous report on centenarians. There should be several possible reasons for this increase. First, a specific factor V haplotype may have a protective effect or vice versa. Other gene combinations may have protective or causative effect on the risk possibility of FVL. A population scale Genomewide Association Study (GWAS) might be instrumental in order to identify these possible gene combinations. Further, if this difference would be verified by large number of controls, this might be a clue for the advantageous role of FVL in natural selection.

Cerebral Sinovenous Thrombosis in Children and Neonates Clinical Experience, Laboratory, Treatment, and Outcome

Our aim is to present the etiology and risk factors for cerebral sinovenous thrombosis (CSVT) and the radiological findings, anticoagulant therapy used, and treatment outcome of patients with CSVT. This study included 12 patients who were treated for CSVT at the Ankara University, School of Medicine, Department of Pediatric Neurology. This study included 5 girls (41.7%) and 7 boys (58.3%) with a mean age of symptom onset of 5.2 ± 6.29 years (range: 0-18 years), who were followed at our institution for a mean of 1.8 ± 1.73 years (range: 0-6.5 years). Among the patients, 3 had no risk factors, 2 had 1 risk factor, and 7 had multiple risk factors. Anticoagulant therapy was administered to 4 patients, of which 1 had neurological sequelae; neurological sequelae or exitus occurred in 4 of the 8 patients who did not receive anticoagulant therapy. The present findings showed that appropriate prophylaxis in appropriately selected patients reduced the rate of recurrence of CSVT.