A novel HLA-B null allele (B*4022N) generated by a nonsense codon in the alpha1 domain.
We describe in this work a novel HLA-B null allele designated B*4022N. This new variant was found in a Caucasian individual who was serologically typed for one HLA-B allele as a B-blank, Bw-blank. Retrospective DNA typing by polymerase chain reaction using sequence-specific primers (PCR-SSP) has established the correspondence of this blank allele with the classical HLA-B*4001 allele. Nucleotide sequence analysis of exon 2 and 3 has revealed the presence of two adjacent point mutations at position 170 and 171 of exon 2 (GG to TT). While the first difference is silent, the second leads to the creation of a nonsense codon at position 58 of the alpha1 domain, providing the most likely mechanism underlying the observed null phenotype.
Tamouza
R
R
Laboratoire d'Immunologie et d'Histocompatibilité, Hôpital Saint Louis, and INSERM U396, Paris, France. tamouza@histo.chu-stlouis.fr
Sadki
K
K
Schaeffer
V
V
Carbonnelle
E
E
Tatari
Z
Z
Chabod
J
J
Toubert
A
A
Raffoux
C
C
Sayada
C
C
Charron
D
D
D000483:Alleles; D018389:Codon, Nonsense; D018388:Codon, Terminator; D017931:DNA Primers; D015235:HLA-B Antigens / Q000737:chemistry / Q000235:genetics*; D006801:Humans; D017354:Point Mutation; D016133:Polymerase Chain Reaction; D017434:Protein Structure, Tertiary
D018389:Codon, Nonsense; D018388:Codon, Terminator; D017931:DNA Primers; D015235:HLA-B Antigens