title: Identification of HLA-A*0111N: a synonymous substitution, introducing an alternative splice site in exon 3, silenced the expression of an HLA-A allele.
abstract: A new variant of the HLA-A*010101 allele designated as HLA-A*0111N, previously known as HLA-A*010101var, was identified in a patient requiring a stem-cell transplantation. The patient was typed by serologic methods as HLA-A2 homozygous and by sequence-based typing (SBT) as A*010101,020601. Flow-cytometric (FCM) analysis with 11 human monoclonal antibodies (mAbs) for the A1 molecule confirmed lack of any cell membrane expression of the A*0111N allele. One-dimensional isoelectric focusing (1D-IEF) of total cell lysate from the patient's cells revealed no cell surface and cytoplasmic A1 protein expression, whereas the HLA-A2 molecule was identified by both FCM analysis and 1D-IEF. DNA sequence analysis showed the presence of a synonymous substitution from G to T at position 597 in codon 175. RNA SBT revealed a deletion of 24 bp in exon 3, position 596 through 619, encoding codons 175 through 182 of the HLA-A*0111N allele. The synonymous substitution introduced a new splice site, resulting in an efficient splicing, because no classical A1 protein could be detected in the patient. This alternative splicing prevented the translation into a correct and stable class I molecule expression on the cell surface.
authors.affiliation: Department of Pathology, University Medical Centre Utrecht (UMC-U), Utrecht, The Netherlands.
authors.forename: Judith
authors.initials: J
authors.lastname: Reinders
authors.forename: Erik H
authors.initials: EH
authors.lastname: Rozemuller
authors.forename: Henny G
authors.initials: HG
authors.lastname: Otten
authors.forename: Anna J S
authors.initials: AJ
authors.lastname: Houben
authors.forename: Anne
authors.initials: A
authors.lastname: Dormoy
authors.forename: Arend
authors.initials: A
authors.lastname: Mulder
authors.forename: Jan G
authors.initials: JG
authors.lastname: van den Tweel
authors.forename: Eefke J
authors.initials: EJ
authors.lastname: Petersen
authors.forename: Marcel G J
authors.initials: MG
authors.lastname: Tilanus
mesh_terms: D000483:Alleles; D017398:Alternative Splicing; D019943:Amino Acid Substitution; D004252:DNA Mutational Analysis; D005091:Exons / Q000235:genetics; D005434:Flow Cytometry; D020868:Gene Silencing; D015234:HLA-A Antigens / Q000096:biosynthesis / Q000235:genetics*; D006801:Humans; D008297:Male; D008875:Middle Aged; D017422:Sequence Analysis, DNA; D012703:Serotyping
chemical_list: D015234:HLA-A Antigens