Linkage disequilibrium of polymorphic RAET1 genes in Thais.

Retinoic acid early transcripts-1 (RAET1) or unique long 16 (UL-16) binding proteins (ULBPs) is a gene cluster encoding for molecules acting as ligands to natural killer group 2 D (NKG2D), a receptor expressed on immune cells. Binding of these ligands to the receptor activates immune cells leading to killing of tumor cells and also viral-infected cells. The information on polymorphism of RAET1 is limited. In this report, we analyze the linkages between four polymorphic RAET1 genes: RAET1E, RAET1G, RAET1H and RAET1L, in 318 unrelated Thais. The strongest linkage disequilibrium was found between RAET1E and RAET1G, with P-value, D' and r(2) of <5.0 x 10(-5), 0.707 and 0.840, respectively. RAET1E(*)001 was found to be in linkage disequilibrium with RAET1G(*)002, and RAET1E(*)002 with RAET1G(*)001. Evidently, there were possible RAET1 haplotypes with haplotype frequencies of more than 10% consisting of RAET1E(*)001; RAET1G(*)002; RAET1H(*)001; RAET1L(*)001 and RAET1E(*)002; RAET1G(*)001; RAET1H(*)002; RAET1L(*)003. This study provides basic information on polymorphisms of RAET1 and possible RAET1 haplotypes in Thais.