Identification of two new alleles, IGHV3-23*04 and IGHJ6*04, and the complete sequence of the IGHV3-h pseudogene in the human immunoglobulin locus and their prevalences in Danish Caucasians

More than 100 variable (V), 27 diversity (D), and six joining (J) genes are encoded in the human heavy chain locus, and many of these genes exists in different allelic forms. The number of genes and the allelic differences help to create diversity in the immunoglobulin receptors, a key feature of the adaptive immune system. We here report the identification of two novel and seemingly functional alleles of human heavy chain genes. The variable IGHV3-23*04 allele is found with an allele frequency of 0.21 amongst Danish Caucasians, whereas the novel joining IGHJ6*04 allele is rare (allele frequency 0.02). We also report the full sequence of IGHV3-h. The gene exists in two allelic forms but is only found in 58% of the Danish Caucasians studied. The methionine translation initiation codon is mutated, ATG→AAG, and we therefore propose that the gene is a pseudogene incapable of being translated.