Introduction: The epigenetic modifications can significantly affect and alter the gene activity by regulating their expression, having direct impact on various processes in human body. Epigenetic processes are involved in ethiopathogenesis of many diseases. From this point of view, MHC genes are very important as they were linked to many autoimmune disorders, for example type 1 diabetes mellitus. In general autoimmune diseases appear to be connected to certain MHC class II genes. Aims: The aim of this thesis is to determine the relationship between expression levels and histone modifications present in the promoter area of MHC class II gene, DQA1. Moreover, we also analyze and compare the DQA1 gene mRNA expression depending on the QAP promoter allele. Methods: We isolated both nucleic acids (DNA and RNA) and leukocytes from peripheral blood samples collected from voluntary donors. DNA was utilized for genotypization of individuals. RNA was subjected to reverse transcription and the quantitative PCR was performed in order to determine the level of expression. Leukocytes were used for chromatin immunoprecipitation, which was evaluated using quantitative PCR. Results: The expression level of QAP allele 3.1 was found to be higher than for the rest of the alleles Allele 4.1A showed, on the other hand,...

Anorexia Nervosa (AN) and Bulimia Nervosa (BN) are diseases with considerable individual variation. Genetic background plays an important role in disease susceptibility and severity. To evaluate the relationship between certain genetic loci and diseases subtypes we genotyped and analysed evolution of selected clinical parameters. We investigated a group of 75 pacients with AN (1. study), 127 DSM-4 and ICD-10 diagnosed patients with AN and BN (2. study), and contributed to sample of 2907 AN patients in large GWAS study. Results from the 1st study support association of polymorphism -1438G/A in serotonine receptor 5-HT2A with AN and compare the results from other studies with metaanalyses. In next, polymorphism responsible for the serotonine neurotransmission (serotonine transporter 5-HTT, polymorphisms LPR and VNTR) the study shows different association trend of LPR with AN in Czech population compared to other studies. 5-HTT VNTR polymorphism had no observed association. The second study investigated the role of hemeoxygenase 1 (plays a pivotal role in metabolic stress protecting cells) in eating disorders, in interaction with enviromental stress. We investigated the usefulness of an aggregate measure of the risks of AN and BN that is based on genetic susceptibility loci and the added effect of...