The tetranucleotide repeat locus C2_4_4 situated in the HLA class I region (6p21.3) and the HLA-ABC specificities were investigated in an Austrian population sample of 240 unrelated Caucasoid individuals. The analysis of the linkage disequilibrium between C2_4_4 and HLA class I showed several significant values, especially when factors coded for by so-called "superhaplotypes" were considered; such linkage disequilibria are of importance for the practical use of HLA coded short tandem repeats.