Polymorphism of HLA-A, -B, -DRB1, -DQA1 and -DQB1 haplotypes in a Croatianpopulation

We describe for the first time extended haplotypes in a Croatian population . The present study gives the HLA-A, -B, -DRB1, -DQA1 and -DQB1 allele and haplotype frequencies in 105 families with at least two offspring. All indi viduals were studied by conventional serology for HLA class I antigens (A a nd B), while class II alleles (DRB1, DQA1, DQB1) were typed using the PCR-S SOP method. HLA genotyping was performed by segregation in all 105 families . For extended haplotype analysis, 420 independent parental haplotypes were included. Fourteen HLA-A, 18 HLA-B, 28 DRB1, 9 DQA1 and 11 DQB1 alleles we re found in the studied population. Most of the DRB1 alleles in our populat ion had an exclusive association with one specific DQA1-DQB1 combination. T his strong linkage disequilibrium within the HLA class II region is often e xtended to the HLA-B locus. A total of 10 HLA-A, -B, -DRB1, -DQA1, -DQB1 ha plotypes were observed with a frequency less than or equal to 1.0%. The thr ee most frequent haplotypes were HLA-A1, B8, DRB1*0301, DQA1*0501, DQB1*020 1; HLA-A3, B7, DRB1*1501, DQA1*0102, DQB1*0602 and HLA-A24, B44, DRB1*0701, DQA1*0201, DQB1*02. These results should provide a useful reference for fu rther anthropological studies, transplantation studies, and studies of asso ciations between HLA and diseases.