title: Expression defect of an HLA-A*24 allele associated with DNA methylation in a normal individual.
abstract: Non-expressed HLA alleles become a potential problem in the transition of the HLA typing methodology from serologic typing to more accurate DNA typing. In this study, a novel nonexpressed A*24 allele identified from two members of a Korean family was characterized. At the DNA sequence level, the nonexpressed allele (A*24023) is apparently normal; the complete genomic sequence was identical to HLA-A*2402101, from the 5'-upstream region to the 3'-downstream region, except for a single silent substitution at codon 211 (GCG-->GCA) in exon 4. A DNA methylation analysis using methylation-sensitive restriction enzymes, however, showed that the nonexpressed A*24023 allele from an apparently normal individual was highly methylated in regions covering exons and introns as well as the 5'-upstream region. This result suggests that hypermethylation of the HLA-A gene may induce gene inactivation in the normal individuals.
authors.affiliation: Hallym Institution for Genome Application, Hallym University Sacred Heart Hospital, Anyang, Korea. leekw@hallym.or.kr
authors.forename: K W
authors.initials: KW
authors.lastname: Lee
authors.forename: J-Y
authors.initials: JY
authors.lastname: Shin
authors.forename: J-Y
authors.initials: JY
authors.lastname: Lee
mesh_terms: D019175:DNA Methylation; D015870:Gene Expression; D015234:HLA-A Antigens / Q000096:biosynthesis / Q000235:genetics*; D006801:Humans; D017422:Sequence Analysis, DNA
chemical_list: D015234:HLA-A Antigens