title: Second HLA-A*68 null allele, A*6818 N, identified.
abstract: A second HLA-A*68 null allele, HLA-A*6818 N, was identified in our laboratory after discrepant results were obtained between class I serological and molecular typing in a male patient suffering from narcolepsy. HLA-A*6818 N displays a sequence identical to that of the HLA-A*6802 allele, except in exon 2 where 20 nucleotides inserted at codon position 48 are a repeat of the 20 preceding nucleotides. This duplication creates a shift of the reading frame, which leads to a premature non-sense codon at position 59 of the null allele.
mesh_terms: D000483:Alleles; D001483:Base Sequence; D003062:Codon / Q000235:genetics; D005091:Exons / Q000235:genetics; D005192:Family Health; D005260:Female; D016368:Frameshift Mutation / Q000235:genetics; D020440:Gene Duplication; D005819:Genetic Markers / Q000235:genetics; D020022:Genetic Predisposition to Disease / Q000235:genetics; D015234:HLA-A Antigens / Q000235:genetics*; D006239:Haplotypes / Q000235:genetics; D006650:Histocompatibility Testing; D006801:Humans; D008297:Male; D008969:Molecular Sequence Data; D017422:Sequence Analysis, DNA
chemical_list: D003062:Codon; D005819:Genetic Markers; D015234:HLA-A Antigens; C053029:HLA-A*68 antigen