MICA A8: a new allele within MHC class I chain-related A transmembrane region with eight GCT repeats.

Analysis of the MICA gene revealed a trinucleotide repeat (GCT) microsatellite polymorphism within the transmembrane region. So far, seven alleles of the exon 5 of the MICA gene, which consist of 4, 5, 6, 7, 9, and 10 repetitions of GCT or five repetitions of GCT with an additional nucleotide insertion (GGCT), have been identified. These alleles have been accordingly named A4, A5, A6, A7, A9, A10, and A5.1, and the sizes are, respectively, 179 bp, 182 bp, 186 bp, 189 bp, 194 bp, 197 bp, and 185 bp. We analyzed 1100 Italian subjects for MICA exon 5 microsatellite polymorphism. A new peak corresponding to 191-bp size was observed in one individual, and we confirmed the presence of new polymorphism in exon 5 by sequencing, which consisted of eight GCT repeats. We named this allele, as a current nomenclature, MICA8.