HLA Nomenclature

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The standardized HLA gene and allele nomenclature is managed by the WHO Nomenclature Committee for Factors of the HLA System.  A high-level summary of their nomenclature system is reproduced here for easy reference.  A thorough and detailed review of the HLA naming schema is available online.



Fig. 1

Fig. 1 shows the standard naming convention for HLA alleles.  It includes the HLA gene name, the HLA allele group for a specific gene, a specific non-synonymous allele (i.e. one that changes a protein amino acid sequence), a specific synonymous allele (i.e. one that does not change a protein amino acid sequence), non-CDS (coding sequence) alleles (i.e. introns, 5′-UTR’s, 3′-UTR’s, etc.) and suffixes that denote protein expression level.


HLA FieldDefinition
HLAThe HLA region and prefix for an HLA gene
HLA-DRB1A particular HLA locus i.e. DRB1
HLA-DRB1*13A group of alleles that encode the DR13 antigen
or sequence homology to other DRB1*13 alleles
HLA-DRB1*13:01A specific HLA allele
HLA-DRB1*13:01:02An allele that differs by a synonymous mutation from DRB1*13:01:01
HLA-DRB1*13:01:01:02An allele that contains a mutation outside the coding region from DRB1*13:01:01:01
HLA-A*24:09NA 'Null' allele. An allele that is not expressed
HLA-A*30:14LAn allele that encodes a protein with significantly reduced
or 'Low' cell surface expression
HLA-A*24:02:01:02LAn allele that encodes a protein with significantly reduced
or 'Low' cell surface expression,
where the mutation is found outside the coding region
HLA-B*44:02:01:02SAn allele that encodes a protein which is expressed as a 'Secreted' molecule only
HLA-A*32:11QAn allele which has a mutation that has previously been shown
to have a significant effect on cell surface expression,
but where this has not been confirmed and its expression remains 'Questionable'


Table 1

Table 1 shows the definitions of HLA alleles at various levels of resolution.  The HLA nomenclature described in Fig. 1 and Table 1 is reflected in the HLA reports that we deliver for each HLA sample and HLA sequencing run.  If you’re in receipt of these reports you may want to refer to the HLA nomenclature described here.