A novel HLA‐B null allele (B*4022N) generated by a nonsense codon in the α1 domain

Abstract
We describe in this work a novel HLA‐B null allele designated B*4022N. This new variant was found in a Caucasian individual who was serologically typed for one HLA‐B allele as a B‐blank, Bw‐blank. Retrospective DNA typing by polymerase chain reaction using sequence‐specific primers (PCR‐SSP) has established the correspondence of this blank allele with the classical HLA‐B*4001 allele. Nucleotide sequence analysis of exon 2 and 3 has revealed the presence of two adjacent point mutations at position 170 and 171 of exon 2 (GG to TT). While the first difference is silent, the second leads to the creation of a nonsense codon at position 58 of the α1 domain, providing the most likely mechanism underlying the observed null phenotype ( Note).