Ivana Horvat

Association of Polymorphisms in Coagulation Factor Genes and Enzymes of Homocysteine Metabolism With Arterial Ischemic Stroke in Children

Despite the identification of a wide range of inherited and acquired risk factors for arterial ischemic stroke (AIS) in children, genetic risk factors are incompletely characterized and may vary among different populations. We investigated the role of individual and combined inherited prothrombotic and intermediate-risk factors in 73 children with perinatal (n = 35) and childhood AIS (n = 38) and 100 age- and sex-matched controls. Ten polymorphisms in 8 candidate genes encoding coagulation and fibrinolytic proteins (factor V [FV] Leiden, FV HR2, factor II [FII] G20210A, β-fibrinogen [β-FBG]-455G>A, factor XIII [FXIII]-A p.Val34Leu, plasminogen activator inhibitor 1 4G/5G), homocysteine metabolism (methylenetetrahydrofolate reductase [MTHFR] C677T, MTHFR A1298C), and intermediate-risk factors (angiotensin-converting enzyme I/D, apoE ∊2-4) were detected using a multilocus genotyping assay. Allele-specific polymerase chain reaction was used for the determination of human platelet alloantigens (HPA-1, HPA-2, HPA-3, and HPA-5). Factor V Leiden was associated with an increased risk of AIS (odds ratio [OR]: 4.72, 95% confidence interval [CI]: 1.22-18.27) and perinatal AIS (OR: 8.29, 95% CI: 1.95-35.24). Human platelet antigen-3b allele carriers had a 2-fold lower risk of AIS (OR: 0.51, 95% CI: 0.26-0.98) and perinatal AIS (OR: 0.40, 95% CI: 0.18-0.92). A 2.21-fold increased risk of childhood AIS (95% CI: 1.03-4.73) was identified in FXIII-A Leu34 allele carriers. Combined FV Leiden/FV HR2, FV Leiden/MTHFR A1298C, FV Leiden/MTHFR C677T/MTHFR A1298C, and FV Leiden/FV HR2/MTHFR A1298C heterozygosity was identified in children with AIS but not in controls, which revealed a statistically significant difference. This case–control study shows that besides already documented association between FV Leiden and AIS, other previously unreported polymorphisms (FXIII-A p.Val34Leu, HPA-3) and several genotype combinations that always include heterozygous FV Leiden can be related to AIS in Croatian population.

Development and validation of a rapid method for genotyping three P-selectin gene polymorphisms based on high resolution melting analysis

High resolution melting (HRM) analysis is one of the newer, reliable, and sensitive genotyping techniques, which offers considerable time and cost savings. P‐selectin is an adhesion molecule that has a role in the initial phases of leukocyte adhesion to stimulated platelets and endothelial cells in inflammation. Multiple polymorphisms in P‐selectin gene (SELP) that affect the protein sequence have been described. The aim of this study was to design, optimize, and validate a simple and rapid in‐house HRM‐based method for genotyping the NM_003005.3:c.992G>A (c.992G>A), NM_003005.3:c.1918G>T (c.1918G>T), and NM_003005.3:c.2266A>C (c.2266A>C) SELP polymorphisms.

Serum chitotriosidase: a circulating biomarker in polycythemia vera

ABSTRACT Objectives: Serum chitotriosidase activity (CHIT1) is a biomarker of macrophage activation with an important role in inflammation-induced tissue remodeling and fibrosis. Macrophages have been described to play a crucial role in regulating pathological erythropoiesis in polycythemia vera (PV). The aim of this study was to evaluate CHIT1 in patients diagnosed with Philadelphia-negative myeloproliferative neoplasms (MPNs). Methods: Using fluorometric assay, we measured CHIT1 in 28 PV, 27 essential thrombocythemia (ET), 17 primary myelofibrosis (PMF), 19 patients with secondary myelofibrosis and in 25 healthy controls. Results: CHIT1 was significantly higher in PV (p < .001) and post-PV myelofibrosis (MF) transformation (post-PV MF) (p = .020), but not in ET (p = .080), post-ET MF transformation (p = .086), and PMF patients (p = .287), when compared to healthy controls. CHIT1 in PV was positively correlated with hemoglobin (p = .026), hematocrit (p = .012), absolute basophil count (p = .030) and the presence of reticulin fibrosis in the bone marrow (p = .023). Discussion: A positive correlation between CHIT1 and these distinct laboratory PV features might imply macrophages closely related to clonal erythropoiesis as cells of CHIT1 origin. In addition, a positive association between CHIT1 and reticulin fibrosis might indicate its potential role in PV progression. Conclusion: CHIT1 might be considered as a circulating biomarker in PV. Additional studies are needed to clarify the role of CHIT1 in promoting disease progression and bone marrow fibrosis in PV.

The incidence of atypical patterns of BCR-ABL1 rearrangement and molecular-cytogenetic response to tyrosine kinase inhibitor therapy in newly diagnosed cases with chronic myeloid leukemia (CML).

Background To analyze the frequency of atypical fluorescence in situ hybridization signal patterns and estimate the complete cytogenetic response (CCyR) and major molecular response (MMR) during 12 months of tyrosine kinase inhibitor therapy in patients with newly diagnosed chronic myeloid leukemia. Methods The study included bone marrow and peripheral blood samples from 122 patients with newly diagnosed chronic myeloid leukemia. Detection of the breakpoint cluster region—Abelson fusion gene (BCR-ABL1) was performed using fluorescence in situ hybridization with a dual-color dual-fusion translocation probe, and MMR analysis was performed using the real-time quantitative polymerase chain reaction method. Results Variant translocation was determined in 10 samples and a deletion on the derivative chromosome 9 (del/der(9)) was found in 20 samples. The rates of CCyR and MMR were similar between patients with reciprocal translocation, variant translocation, deletion of derivative BCR, or ABL1-BCR fusion gene. The Kaplan-Meier test did not show any significant differences in the rates of CCyR and MMR among those groups of patients. Conclusion The frequencies of variant translocation and del/der(9) in the present study agree with the results of other studies performed worldwide. No differences were observed in the rates of CCyR and MMR between patients with atypical patterns and reciprocal translocation.