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Lung cancer is a serious health problem, since it is one of the leading causes for death worldwide. Molecular–cytogenetic studies could provide reliable data about genetic alterations which could be related to disease pathogenesis and be used for better prognosis and treatment strategies. We performed whole genome oligonucleotide microarray-based comparative genomic hybridization in 10 samples of non-small cell lung cancer. Trisomies were discovered for chromosomes 1, 13, 18 and 20. Chromosome arms 5p, 7p, 11q, 20q and Хq were affected by genetic gains, and 1p, 5q, 10q and 15q, by genetic losses. Microstructural (

The aetiology of schizophrenia is still unknown but it involves both heritable and non-heritable factors. DNA methylation is an inheritable epigenetic modification that stably alters gene expression. It takes part in the regulation of neurodevelopment and may be a contributing factor to the pathogenesis of brain diseases. It was found that many of the antipsychotic drugs may lead to epigenetic modifications. We have performed 42 high-resolution genome-wide methylation array analyses to determine the methylation status of 27,627 CpG islands. Differentially methylated regions were studied with samples from 20 Bulgarian individuals divided in four groups according to their gender (12 males/8 females) and their treatment response (6 in complete/14 in incomplete remission). They were compared to two age and sex matched control pools (110 females in female pool/110 males in male pool) before and after treatment. We found significant differences in the methylation profiles between male schizophrenia patients with complete remission and control male pool before treatment (C16orf70, CST3, DDRGK1, FA2H, FLJ30058, MFSD2B, RFX4, UBE2J1, ZNF311) and male schizophrenia patients with complete remission and control male pool after treatment (AP1S3, C16orf59, KCNK15, LOC146336, MGC16384, XRN2) that potentially could be used as target genes for new therapeutic strategies as well as markers for good treatment response. Our data revealed major differences in methylation profiles between male schizophrenia patients in complete remission before and after treatment and healthy controls which supports the hypothesis that antipsychotic drugs may play a role in epigenetic modifications.

Breast cancer is currently the most common type of cancer in females. The majority of the hereditary forms of breast cancer are caused by mutations in the BRCA1 and BRCA2 genes, whose main function is the DNA repair of double-strand breaks. Genetic testing of females with a family history of breast cancer is recommended to determine their hereditary predisposition for this type of cancer. The variants with no clear clinical significance may represent a diagnostic challenge when performing targeted resequencing. In this study, DNA samples were obtained from 24 breast cancer patients (mean age, 35±10 years) with a positive family history and from 71 age-matched healthy controls. Informed consent was obtained from all the subjects. Sequence-targeted BRCA1 and BRCA2 libraries were prepared using the TruSeq Custom Amplicon method and sequenced on the Illumina MiSeq system. A wide range of variants were identified in the BRCA1 and BRCA2 genes. Two pathological/presumably pathological variants were detected in the breast cancer patient group: a mutation in BRCA2 at the chromosomal (chr) position chr13:32890665, which affected the first position of the 5’ splice region following exon 2; and a mutation in BRCA1 at chr17:41219635, causing an in-frame triple nucleotide deletion of valine 1688 (8.3%). In the patient and control groups, 7 likely polymorphic variants and 13 common variants were detected in the BRCA1 and BRCA2 genes. To the best of our knowledge, this study was the first to identify 3 common polymorphisms in BRCA2, characteristic solely of the Bulgarian population, including chr13:32973737, T/-, a single-nucleotide polymorphism (SNP) within the 3’-UTR of exon 27; chr13:32973280, A/-, a mononucleotide deletion within the 5’-UTR of exon 27; and chr13:32973924, T/-, a mononucleotide deletion downstream of the gene sequence. To the best of our knowledge, this study was the first to apply next-generation sequencing of the BRCA1 and BRCA2 genes in a Bulgarian population, prompting further investigation for local founder mutations and variants characteristic for this particular region.

Infertility affects 10% to 15% of all couples. In about 40% of the cases the male factor is reported to be the main reason for unsuccessful fertilization. Although in 70% of the male factor infertility cases the etiology is recognizable, in the remaining 30% the reason is unknown and the male infertility is named idiopathic. In the current study, we selected 10 patients with idiopathic infertility, affected by azoospermia and oligoasthenoteratozoospermia. All patients were subjected to DNA analysis for deletions of the Y chromosome and cytogenetic analysis for chromosomal aberrations. After these analyses, the patients without such kind of abnormalities were further analyzed by microarray-based comparative genomic hybridization (array CGH). The cytogenetic analysis revealed two patients with chromosomal mutations—inv (9)(p11;q13) and t(Y;9)(q12.3;q21.1). Two other patients were detected to have deletions of the AZFc region of the Y chromosome. Thus, we applied array CGH analysis for the six patien...

BEN is a primary, chronic tubulointerstitial nephritis characterized with chronic anemia, absence of edema, xantoderma, normal blood pressure and normal findings on the fundus oculi. The disease is distributed in restricted areas in Bulgaria, Romania, Croatia, Bosnia, Former Yugoslavia. Despite numerous studies on genetic and environmental factors and their possible involvement in BEN, its etiopathogenesis still remains elusive. Our recent study aim to elucidate the possible epigenetic component in BEN development. Whole genome DNA array methylation analysis was applied to compare the methylation profiles of male and female BEN patients from endemic regions in Bulgaria and Serbia and healthy controls. All three most prominent candidate genes with aberrations in the epigenetic profile discovered with this study are involved in the inflammatory/immune processes and oncogenesis. These data are in concordance with the reported pathological alterations in BEN. This research supports the role of epigenetic changes in BEN pathology. Exome sequencing of 22.000 genes with Illumina Nextera Exome Enrichment Kit revealed three mutant genes (CELA1, HSPG2, and KCNK5) in BEN patients which encode proteins involved in basement membrane/extracellular matrix and vascular tone, tightly connected to process of angiogenesis. We suggest that an abnormal process of angiogenesis plays a key role in the molecular pathogenesis of BEN.

Autism spectrum disorders (ASDs) constitute a group of behaviorally-defined conditions whose main features are qualitative changes in social interactions, defect in communication abilities, and repetitive and stereotyped interests and activities. ASDs are disorders which can be either isolated, or syndromic. The exact etiology of autism remains unknown, although it is likely to result from a complex combination of genetic and nongenetic factors. One genetic mechanism known to be associated with ASDs is submicroscopic chromosomal imbalances that are undetectable at the level of traditional cytogenetic analysis. Array-based comparative genomic hybridization (array CGH) is a powerful and high-resolution approach for detection of DNA copy number variants (CNVs). Forty-seven autistic patients were investigated using a whole-genome oligo-based array CGH, covering the genome at an average distance of 35 kb. Four clinically significant rearrangements, ranging from 494 kb to 3.47 Mb in size, were identifie...

We present here the details of a six-month male infant with multiple congenital anomalies and developmental delay with an apparently balanced karyotype - 46, XY, inv(9)(p11q13) - and revealed by ol...

Array-based comparative genomic hybridization (array CGH) is a powerful and high-resolution approach for detection of DNA copy number gains and losses, associated to chromosomal abnormalities, many of which are below the detection limit of the routine cytogenetic analysis.Technological improvements to acquire higher resolution have led to generation of novel microarray platforms harboring larger numbers of shorter DNA sequences (oligonucleotides). Two main technologies are currently used for DNA copy number genome profiling—the Bacterial Artificial Chromosome and the oligo-based CGH arrays.In this study we present a comparison of two array-based platforms for genome-wide copy number screening in a group of six patients with idiopathic congenital anomalies and mental retardation or developmental delay. Each of our patients was studied separately with BAC and oligo-based microarray and the imbalances found were FISH confirmed.Our results indicated that the oligo-based platform had higher sensitivity...

Bronchial asthma is the most common chronic disease in infancy worldwide. Genetics factors play important part in the pathogenesis of bronchial asthma. The aim of the present study is by the method of quantitative PCR in real time to establish changes in gene expression, related to the immune response in patients with bronchial asthma and healthy controls. Changes in the pointed genes cause changes in the expression of various inflammatory proteins. Analysis of gene expression, which is at the basis of functional genomics, gives much more precious information on the effect of gene changes on the course of the disease. At comparison of gene expression in the separate clinical groups was found that the greater part of the 84 studied genes, were with increased expression.

Schizophrenia is one of the major psychiatric disorders. It is a disorder of complex inheritance, involving both heritable and environmental factors. DNA methylation is an inheritable epigenetic modification that stably alters gene expression. We reasoned that genetic modifications that are a result of environmental stimuli could also make a contribution. We have performed 26 high-resolution genomewide methylation array analyses to determine the methylation status of 27,627 CpG islands and compared the data between patients and healthy controls. Methylation profiles of DNAs were analyzed in six pools: 220 schizophrenia patients; 220 age-matched healthy controls; 110 female schizophrenia patients; 110 age-matched healthy females; 110 male schizophrenia patients; 110 age-matched healthy males. We also investigated the methylation status of 20 individual patient DNA samples (eight females and 12 males. We found significant differences in the methylation profile between schizophrenia and control DNA pools. We found new candidate genes that principally participate in apoptosis, synaptic transmission and nervous system development (GABRA2, LIN7B, CASP3). Methylation profiles differed between the genders. In females, the most important genes participate in apoptosis and synaptic transmission (XIAP, GABRD, OXT, KRT7), whereas in the males, the implicated genes in the molecular pathology of the disease were DHX37, MAP2K2, FNDC4 and GIPC1. Data from the individual methylation analyses confirmed, the gender-specific pools results. Our data revealed major differences in methylation profiles between schizophrenia patients and controls and between male and female patients. The dysregulated activity of the candidate genes could play a role in schizophrenia pathogenesis.

Background Balkan endemic nephropathy (BEN) represents a chronic progressive interstitial nephritis in striking correlation with uroepithelial tumours of the upper urinary tract. The disease has endemic distribution in the Danube river regions in several Balkan countries. DNA methylation is a primary epigenetic modification that is involved in major processes such as cancer, genomic imprinting, gene silencing, etc. The significance of CpG island methylation status in normal development, cell differentiation and gene expression is widely recognized, although still stays poorly understood. Methods We performed whole genome DNA methylation array analysis on DNA pool samples from peripheral blood from 159 affected individuals and 170 healthy individuals. This technique allowed us to determine the methylation status of 27 627 CpG islands throughout the whole genome in healthy controls and BEN patients. Thus we obtained the methylation profile of BEN patients from Bulgarian and Serbian endemic regions. Results Using specifically developed software we compared the methylation profiles of BEN patients and corresponding controls and revealed the differently methylated regions. We then compared the DMRs between all patient-control pairs to determine common changes in the epigenetic profiles. SEC61G, IL17RA, HDAC11 proved to be differently methylated throughout all patient-control pairs. The CpG islands of all 3 genes were hypomethylated compared to controls. This suggests that dysregulation of these genes involved in immunological response could be a common mechanism in BEN pathogenesis in both endemic regions and in both genders. Conclusion Our data propose a new hypothesis that immunologic dysregulation has a place in BEN etiopathogenesis.

Breast cancer is currently the most common type of cancer in females. The majority of the hereditary forms of breast cancer are caused by mutations in the BRCA1 and BRCA2 genes, whose main function is the DNA repair of double-strand breaks. Genetic testing of females with a family history of breast cancer is recommended to determine their hereditary predisposition for this type of cancer. The variants with no clear clinical significance may represent a diagnostic challenge when performing targeted resequencing. In this study, DNA samples were obtained from 24 breast cancer patients (mean age, 35±10 years) with a positive family history and from 71 age-matched healthy controls. Informed consent was obtained from all the subjects. Sequence-targeted BRCA1 and BRCA2 libraries were prepared using the TruSeq Custom Amplicon method and sequenced on the Illumina MiSeq system. A wide range of variants were identified in the BRCA1 and BRCA2 genes. Two pathological/presumably pathological variants were detected in the breast cancer patient group: a mutation in BRCA2 at the chromosomal (chr) position chr13:32890665, which affected the first position of the 5’ splice region following exon 2; and a mutation in BRCA1 at chr17:41219635, causing an in-frame triple nucleotide deletion of valine 1688 (8.3%). In the patient and control groups, 7 likely polymorphic variants and 13 common variants were detected in the BRCA1 and BRCA2 genes. To the best of our knowledge, this study was the first to identify 3 common polymorphisms in BRCA2, characteristic solely of the Bulgarian population, including chr13:32973737, T/-, a single-nucleotide polymorphism (SNP) within the 3’-UTR of exon 27; chr13:32973280, A/-, a mononucleotide deletion within the 5’-UTR of exon 27; and chr13:32973924, T/-, a mononucleotide deletion downstream of the gene sequence. To the best of our knowledge, this study was the first to apply next-generation sequencing of the BRCA1 and BRCA2 genes in a Bulgarian population, prompting further investigation for local founder mutations and variants characteristic for this particular region.

Objective The early detection of NSCLC is of importance because it provides chances for better outcomes. The aim of the study was to explore the clinical utility of EGFR and hTERT mRNA expression as markers for diagnosis of NSCLC. Methods EGFR and hTERT mRNA were quantified by quantative reverse transcription real time polymerase chain reaction in plasma of 45 non-small cell lung cancer (NSCLC) and 40 chronic obstructive pulmonary disease (COPD) patients, selected by certain spirometric characteristics that made them at high risk of developing lung cancer in future. Results The gene expression level of each gene was calculated and given as a relative quantity–-RQ. EGFR gene expression was found in all lung cancer patients. The mean level of expression was RQ = 29.39. hTERT mRNA could be detected in 88% of patients. The mean expression ratio in them was RQ = 17.31. Only 50% of the high risk patients turned to be positive for EGFR. The level of their expression was RQ = 2.09. The plasma levels of hTERT could be detected in 17 (42.5%) patients of the high risk COPD group. Their mean level of expression was RQ = 1.02. A statistically significant difference in EGFR and hTERT mRNA expression could be observed between the two groups of patients–-p = 0.0001. Conclusion EGFR and hTERT mRNA are potential markers for lung cancer diagnosis, whose clinical importance should be replicated in a larger cohort of patients.

Objective The early detection of NSCLC is of importance because it provides chances for better outcomes. The aim of the study was to explore the clinical utility of EGFR and hTERT mRNA expression as markers for diagnosis of NSCLC. Methods EGFR and hTERT mRNA were quantified by quantative reverse transcription real time polymerase chain reaction in plasma of 45 non-small cell lung cancer (NSCLC) and 40 chronic obstructive pulmonary disease (COPD) patients, selected by certain spirometric characteristics that made them at high risk of developing lung cancer in future. Results The gene expression level of each gene was calculated and given as a relative quantity–-RQ. EGFR gene expression was found in all lung cancer patients. The mean level of expression was RQ = 29.39. hTERT mRNA could be detected in 88% of patients. The mean expression ratio in them was RQ = 17.31. Only 50% of the high risk patients turned to be positive for EGFR. The level of their expression was RQ = 2.09. The plasma levels of hTERT could be detected in 17 (42.5%) patients of the high risk COPD group. Their mean level of expression was RQ = 1.02. A statistically significant difference in EGFR and hTERT mRNA expression could be observed between the two groups of patients–-p = 0.0001. Conclusion EGFR and hTERT mRNA are potential markers for lung cancer diagnosis, whose clinical importance should be replicated in a larger cohort of patients.