Frequencies of the LILRA3 6.7-kb deletion are highly differentiated among Han Chinese subpopulations, and involved in ankylosing spondylitis predisposition

Leukocyte immunoglobulin-like receptor A3 (<i>LILRA3</i>) belongs to the multigene LILR family with unique feature of a presence or absence of 6.7-kb variation among individuals. The frequencies of the 6.7-kb<i> </i>deletion vary widely across populations, but so far it has not been carefully investigated among Han Chinese subpopulations. Furthermore, we previously identified the non-deleted (functional) <i>LILRA3</i> as a novel genetic risk for multiple autoimmune diseases. We undertook current study to investigate i) the frequencies of 6.7-kb deletion among Han Chinese subpopulations. ii) whether the functional <i>LILRA3 </i>is a novel susceptibility factor for ankylosing spondylitis (AS), and iii) whether <i>LILRA3</i> influences the disease activity in AS.