A deletion in exon 3 results in a new HLA-A*01 null allele (A*0115N) in a Martinican woman.

We report the identification of a new HLA-A null allele, HLA-A0115N. This null allele has been identified within the A01 group by a combination of serological and molecular typing [Polymerase chain reaction (PCR) sequence-specific primers, PCR sequence-specific oligoprobes and sequence-based typing (SBT)] in a potential intrafamilial bone marrow donor from Martinique (French West Indies). To characterize this A01 null allele, we performed DNA typing by PCR-SBT on genomic DNA from the beginning of exon 2 (position 84) through the end of the exon 4 (position 895) and revealed a nucleotide deletion at the end of the exon 3. This sole difference between the new allele and the HLA-A0101 generates a premature stop codon (TGA) in the beginning of exon 4. This deletion most likely explains the lack of cell surface expression of the encoded protein despite the presence of A01 allele. The absence of correct expression of the antigen on the cell surface was confirmed by one-dimensional isoelectric focusing (1D-IEF). To date, this is the fourth null allele described within the A01 group.