Screening of somatic mutations in the JAK2 and CALR genes by high-resolution melting curve analysis.

Somatic mutations associated with oncological diseases, including Ph-myeloproliferative neoplasms (Ph-MPN), are very diverse, occur with different frequencies and different allelic burden levels. Therefore, at the initial stage of performing molecular-genetic diagnostic procedures, it is desirable to be able to conduct screening tests in the laboratory. This is especially important when analyzing rare and diverse mutations. Analysis of high resolution melting curves (HRM analysis), which has high sensitivity and is suitable for screening all types of mutations, in a number of studies is proposed for the analysis of Ph-MPN associated mutations in the JAK2 and CALR genes. For analysis of somatic mutations in the majority of literature sources that we reviewed, the authors use the LightCycler (Roche) thermocycler and much rarely the CFX96 (Bio-Rad), which is often presented in Russian scientific and practical and medical organizations. The aim of the study was to screen the somatic JAK2 and CALR mutations by HRM analysis using the CFX96 thermocycler and the Precision Melt Analysis software (Bio-Rad, USA) for patients with Ph-MPN. In the present research, HRM analysis was conducted on the DNA samples from patients with mutations in the JAK2 or in the CALR gene. The Precision Melt Analysis software identified all variants of the analyzed mutations, both a single nucleotide substitution in the JAK2 gene (with allelic burden level in the range of 5-40%), and various indel mutations in the CALR gene (with allelic burden level in the range of 40-50%) Therefore, the HRM analysis that was conducted on the CFX96 allows screening of highly specific mutation for the diagnosis of Ph-MPN in the exon 14 of the JAK2 gene and in the exon 9 of the CALR gene. The inclusion of this screening research in the laboratory testing algorithm improves the efficiency and accessibility of molecular genetic technologies in the diagnosis of Ph-MPN.

[Possible Genetic Predictors of Cardiovascular Complications After Coronary Artery Bypass Surgery].

PURPOSE: to investigate associations of single nucleotide polymorphisms (SNPs) rs2046934, rs1126643, rs5918, rs6065, rs4244285; rs4986893 with cardiovascular complications (CVC) in patients after CABG. MATERIALS AND METHODS: We enrolled in this study 130 patients with stable functional class II-IV angina. After CABG 69 patients received ASA (100 mg of enteric form), 61 patients received dual antiplatelet therapy (ASA 100 mg + clopidogrel 75 mg). Mean follow up period was 10.9±5.2 months. The primary composite endpoint included all-cause mortality, myocardial infarction (MI), and ischemic stroke. The control group comprised 185 healthy volunteers. Platelet function was assessed using light transmission aggregometry with ADP (5µM) and arachidonic acid (1 mM). The following single nucleotide polymorphisms (SNPs) were identified by real-time PCR: rs2046934 (H1/H2) on P2RY12 [encoding platelet ADP receptor] (n=100); rs1126643 (C807T, Phe224Phe) on ITGA2 [encoding collagen receptor] (n=87); rs5918 (176T>C, Leu33Pro) on ITGB3 [encoding fibrinogen receptor) (n=91); rs6065 (Thr145Met) on GP1BA [encoding platelet receptor for Von Willebrand factor] (n=114); rs4244285 (*2) (n=84), and rs4986893 (*3) (n=83) on СYP2C19 [encoding cytochrome P450 activity]. RESULTS: The prevalence of rs5918, rs6065, rs4244285, rs4986893, rs2046934 did not differ significantly between patients and healthy volunteers. The mutant allele (T) of ITGA2 was detected more often in healthy volunteers: 67.2 % vs 51.7 % (р=0.021). Before and after CABG there was no significant difference in platelet aggregation between carries and non-carries of the mutant ITGA2 allele. Number of CVCs registered during follow-up was 12: 3 strokes, 6 MIs, 3 deaths. Patients with composite mutant alleles of ITGB3+СYP2C19*2 or СYP2C19*2+ITGA2, and with the mutant allele (*2) of СYP2C19 met end points more often than patients with other gene combinations (wild type homozygotes, presence of one mutant allele of ITGB3 or ITGA2, the composite of mutant alleles of ITGB3+ITGA2 or ITGB3+ITGA2+ СYP2C19*2) (hazard ratio 4.0, 95 % confidence interval 2,19-7.29, р=0.008). Carriers of ITGB3 mutant allele showed higher AA-induced platelet reactivity on the 1st-3rd day after CABG. Amplitude of platelet aggregation in carriers of mutant allele was 27.5 % vs 12.7 % in wild type (p=0.016). No differences in platelet reactivity among carriers of other mentioned mutant alleles and wild types were observed. CONCLUSION: Carriage of the combination of mutant alleles ITGB3+СYP2C19*2 or СYP2C19*2+ITGA2 or СYP2C19*2 is possible predictor of CVC in patients after CABG.

[The development and comparative approbation of methods of increasing sensitivity of detection of mutation V617F in gene JAK2 by pyro-sequencing].

The possibilities of early detection of chronic myelo-proliferative tumors (MPT) are determined by sensitivity of techniques implemented for finding somatic mutation V617F in gene JAK2. The mutation V617F can also be found in individuals without unfolded picture of hematological diseases. The detection of mutation even in low concentrations is associated with increasing of risk of cerebral stroke and thrombosis of arterial and venous vessels. The study was carried out to develop techniques based on COLD polymerase chain reaction and allele-specific polymerase chain reaction targeted to increasing of sensitivity of finding mutation V617F detected using pyro-sequencing. The analytical sensitivity of techniques was evaluated by control samples with different ratio of alleles. For allele-specific polymerase chain reaction analytical sensitivity amounted to 0.25% of mutant allele at concentration of analyzed control sample 10 copies of DNA per mkl. For COLD polymerase chain reaction sensitivity amounted to 0.5% at concentration 10 copies of DNA per mkl. The comparative approbation of techniques was implemented using clinical material obtained from 106 patients with suspicion on MPT. The analysis of clinical samples using COLD polymerase chain reaction revealed 13 (14%) and using technique of allele-specific polymerase chain reaction - 15 (16%) positive samples. In all 15 cases of detection of mutation clinical confirmations of diagnosis of MPT was received. The proposed techniques permit increasing efficiency of amplification of mutant DNA in analyzed samples and hence to increase sensitivity of subsequent analysis of products of amplification using technique of pyro-sequencing. Therefore, the mentioned techniques can be recommended to be applied for confirmation of diagnosis of MPT and early identification of individuals with increased risk of development of venous and arterial thromboses.

[The identifiability of patients with carcinogenic somatic mutation of Junus kinase-2 (V617fJak2) within the framework of programs of dispensary and preventive examinations.]

The article presents results of identification of somatic mutation in in gene Junus kinase-2 (V617F JAK2) in blood samples of persons included in program of dispensarization of adult population and periodic preventive examinations of workers of railroad transport. The technology of allele-specific polymerase chain reaction in real-time in pooled trials from blood samples received by clinical diagnostic laboratory for hematological analysis was developed with purpose of carrying out study. The results of testing among 986 persons aged from 45 to 90 years (median - 69 years) permitted to establish 0.7% of patients (3 females and 4 males) with mutation V617F JAK2. The high thrombogenic potential of mutation V617F JAK2 and its involvement into pathogenesis of chronic myeloid tumors makes appropriate to include test on its detection into menu of laboratory analyses of program of dispensarization of population.

[The detection of Leiden mutation using technique of enzymatic extension of allele-specific primer with double bioluminescent detection (PED-Biolum)].

The article deals with comparing technique of detection of Leiden mutation on the basis of PEXT-reaction with subsequent bioluminescent microanalysis of products with technique based on RT-PCR. The sampling for testing comprised 83 specimen of genome DNA including 35 specimens with known Leiden heterozygote mutation. The commercial kit "SNP-express-PB" (Litex) was used as a comparison test. It is demonstrated that proposed approach is a simple in its application, effective and relatively inexpensive technique of detection of Leiden one-nucleotide polymorphism in gene V of blood coagulation factor. The technique "PED-Biolum" has no differences in comparison with commercial technique RT-PCR concerning ability to detect mutant allele and matches it in parameters of economic effectiveness.

[Analysis of GBA mutations in patients with Parkinson's disease in the Krasnoyarsk region]. / Analiz mutatsii v gene GBA u patsientov s bolezn'yu Parkinsona Krasnoyarskogo regiona.

OBJECTIVE: To analyze mutations and polymorphisms in exons 2, 7, 8, 9, 10 and 11 of the glucocerebrosidase (GBA) gene in patients of the Krasnoyarsk region diagnosed with Parkinson's disease (PD). MATERIAL AND METHODS: Seventy-five patients with sporadic and familial forms of PD were examined. Genomic DNA was isolated from the whole blood of patients. The above mentioned exons of GBA were analyzed using Sanger sequencing. RESULTS: Various changes in the DNA structure of GBA were detected in 11 patients, thus, the overall frequency of variants was 14.7%, and the frequency of pathologically significant mutations (p.L444P, p.D409H, p.H255Q) was 5.3%. CONCLUSION: The frequencies of variants in GBA, one of the most common high-risk factors for PD, in patients of the Krasnoyarsk region turned out to be quite high and comparable to that in patients in other populations of the world. Thus, screening for GBA mutations is relevant for PD patients living in the Krasnoyarsk region as part of genetic counseling at present, and in the future it may be necessary for personalized treatment.

[Lipid peroxidation and erythrocyte membrane permeability in children and adolescents with diabetes mellitus type 1]. / Perekisnoe okislenie lipidov i pronitsaemost' membran éritrotsitov u detei i podrostkov s sakharnym diabetom tipa 1.

The content of malonic dialdehyde (MDA) in erythrocytes and blood plasma as well as the specificity of erythrocyte membrane permeability (EMP) was studied in case of children and teenagers with insulin-dependent diabetes mellitus (IDDM) with respect to a duration and compensation degree of the disease. Eighty-seven children and teenagers with IDDM, aged 7 to 16, and 23 age-matching healthy children and teenagers were examined. The MDA content in erythrocytes and plasma of sick children was found to be increasing yet at the disease onset and did not depend on a duration and compensation degree of diabetes. Erythrocytes of sick children had a lower resistance to the hemolytic action of urea and a higher permeability. As the disease duration was increasing, there was a higher EMP observed at earlier diabetes stages and its decrease with the progressing of diabetes.