Non-expression of HLA-B*5111N is caused by an insertion into the cytosine island at exon 4 creating a frameshift stop codon

The identification of the "blank" allele HLA-B*5111N, which was detected in German and Czech individuals, is described, In the pedigree analysis this new allele segregates with the serological haplotype HLA-A2; B-; DR4 which is frequent in Czech population, The non-expression of B*5111N is caused by the insertion of an additional cytosine molecule at the cytosine island be tween the nucleotides 621-626 (codons 183-185. first three codons of exon 4 ) leading to a frame shift that creates a stop codon at codon 196. This ins ertion may be explained either by conversion with the pseudogene HLA-J or b y dipped-strand mispairing, In order not to overlook the presence of allele s with altered expression in ease of hematopoietic stem cell transplantatio n, both serological and DNA-based typing should be performed.