Identification of a new HLA-DRB4 allele (DRB4*01033) by PCR-SSP and direct sequencing

In this report, we describe the identification of a novel DRB4*01 allele, DRB4*01033, found in two Spanish Caucasian individuals. The new allele was detected during routine HLA typing by an unusual pattern of amplification obtained by polymerase chain reaction using sequence-specific primers (PCR-SSP) that did not match with any of the previously described DRB4 alleles. In order to establish the polymorphism responsible for this pattern exons 2 and 3 of the DRB4 locus were amplified and directly sequenced, The new DRB4*01 allele is identical to DRB4*0103101 except for a single nucleotide substitution in codon 78 (TAC-->TAT). This nucleotide change does not cause an amino acid change as both triplets code for a tyrosine.