title: An HLA-B null allele (B*1526N) with a stop codon in exon 3 generated by a point mutation.
abstract: An HLA-B null allele was identified in a Japanese family during histocompatibility testing for bone marrow transplantation. The propositus was a healthy Japanese woman with three children, and her parents were cousins. Serological HLA typing of the family members indicated that the propositus was homozygous for the A24-Cw4-B blank (B null)-DR4.2-DQ3 haplotype. Total RNA was extracted from peripheral blood of the propositus was converted to first-strand cDNA using reverse transcriptase. The cDNA was amplified by the polymerase chain reaction (PCR) using HLA-B locus-specific primers. The PCR product showed no change in size upon polyacrylamide gel electrophoresis (PAGE) compared to that of normal controls, suggesting that HLA-B gene mRNA was normally expressed. The nucleotide sequence of the cDNA was the same as that of B*1501 except at nucleotide 369 or codon 123, where C was replaced with A; TAC encodes Tyr whereas TAA is a stop codon. This point mutation may have truncated the HLA-B molecule of the propositus, resulting in the negative results we obtained with anti-HLA-B sera.
authors.affiliation: Kyoto Red Cross Blood Center, Japan.
authors.forename: H
authors.initials: H
authors.lastname: Mine
authors.forename: Y
authors.initials: Y
authors.lastname: Ishikawa
authors.forename: M
authors.initials: M
authors.lastname: Hojo
authors.forename: S
authors.initials: S
authors.lastname: Imashuku
authors.forename: K
authors.initials: K
authors.lastname: Tokunaga
authors.forename: T
authors.initials: T
authors.lastname: Juji
authors.forename: H
authors.initials: H
authors.lastname: Saji
authors.forename: S
authors.initials: S
authors.lastname: Yokoyama
mesh_terms: D000328:Adult; D000483:Alleles; D001483:Base Sequence; D003062:Codon / Q000235:genetics*; D003241:Consanguinity; D016384:Consensus Sequence; D004252:DNA Mutational Analysis; D018076:DNA, Complementary / Q000235:genetics; D005091:Exons / Q000235:genetics*; D005260:Female; D005805:Genes, MHC Class I; D015235:HLA-B Antigens / Q000235:genetics*; D006720:Homozygote; D006801:Humans; D008297:Male; D008969:Molecular Sequence Data; D010375:Pedigree; D017354:Point Mutation; D016133:Polymerase Chain Reaction; D016415:Sequence Alignment; D012689:Sequence Homology, Nucleic Acid; D013728:Terminator Regions, Genetic / Q000235:genetics*
chemical_list: D003062:Codon; D018076:DNA, Complementary; D015235:HLA-B Antigens