LST1 and Arthritis: All five genes encode proteins with functions closely related to inflammation, and selective pressure might have conserved this haplotype, such that the variants in this cluster could operate in cis. In addition, higher Ltb and Ncr3 expression, lower Lst1 expression, and the expression of a shorter splice variant of Lst1 correlate with reduced arthritis severity in PIA in the rat (Yau et al., 2016).