Bachelor Thesis Title Association of HLA and Celiac disease Objective To explain the association of HLA and celiac disease and to determine the frequency of HLA-DQA/ HLA-DQB loci in patients with celiac disease. The aim of the short research was to explore the connection between HLA-DQB1*03:01 and HLA-DQB1*03:02 loci and GE. Materials and methods The study was conducted at the Laboratory for tissue typing in KBC Split. It involved 249 patients which were split into two groups. The first group was comprised of 199 patients with the suspicion of Celiac disease while the second group was formed with 50 healthy individuals residing in the region of Dalmatia and was considered to be a control group. For the purpose of genetic testing a technique of DNA isolation was used (commercial kit provided by Roche Diagnostics- High Pure PCR Template Preparation Kit) after which the PCR-SSO method was applied. The frequency of alleles in HLA-DQA1 and HLA-DQB1 loci was determined by direct counting of results. For the analysis of the association between the two groups a 2x2 table was used. If the value was presented as less than 5 a Fisher's exact test was applied (a value of p<0.05. was considered to be statistically significant).   Results The highest frequency of HLA-DQB1 locus in patients with a clinical presentation of Celiac disease was presented by the HLA-DQB1*02 allele (27%). When compared to the control group the results were found to be of statistical significance (p=0.0083). On the contrary, the HLA-DQB1*03:02 allele was present in only 16% of patients. Even though the frequency was greater in the first group compared to the control one, statistical significance was not proven (p=0.1100). Both alleles were identified in 43% of the first group subjects and in 25.4% individuals in the control group. Conclusions The frequency of HLA-DQB1*03:02 is higher than the expected average value for Croatia. With this thesis the connection between specific HLA alleles and the predisposition for the onset of Celiac disease was proven. HLA typing has a momentous impact in the diagnosis of Celiac disease as well as in general clinical practice.