An intronic mutation responsible for a low level of expression of an HLA-A*24 allele.
HLA class I typing performed in parallel by molecular biology and serology has revealed cases where an HLA class I allele was identified but the corresponding antigen on the cell surface was not detected. In the present report, we describe three members of a family in whom an HLA-A24 allele identified at the molecular level was typed as A "blank" by lymphocytotoxicity. This serologically blank antigen was nevertheless faintly detectable by isoelectric focusing (IEF) and FACS analyses. Sequencing of the HLA-A*24 allele from the promoter region to the eighth exonic region revealed a point mutation in the acceptor site of the second intron as compared to the normal HLA-A*24 allele. This mutation could lead to incorrect processing of mRNA through a cryptic acceptor site located at the beginning of the third exon and hence to alternative splicing with a frame shift introducing an early stop codon into the fourth exon.
Laforet
M
M
Laboratoire d'Histocompatibilité Etablissement de Transfusion Sanguine, Strasbourg, France. hla@etss.u-strasbg.fr
Froelich
N
N
Parissiadis
A
A
Bausinger
H
H
Pfeiffer
B
B
Tongio
M M
MM
D000483:Alleles; D004252:DNA Mutational Analysis; D005260:Female; D016368:Frameshift Mutation; D015870:Gene Expression; D005805:Genes, MHC Class I; D015234:HLA-A Antigens / Q000096:biosynthesis / Q000235:genetics*; D059871:HLA-A24 Antigen; D006801:Humans; D007438:Introns / Q000235:genetics*; D008297:Male; D008969:Molecular Sequence Data; D016133:Polymerase Chain Reaction; D012326:RNA Splicing; D016415:Sequence Alignment; D012689:Sequence Homology, Nucleic Acid; D012698:Serologic Tests
D015234:HLA-A Antigens; D059871:HLA-A24 Antigen