TIMP1 and dengue disease: Furthermore, a study on the polymorphism of the distal-less homeobox-1 (DLX1), distal-less homeobox-2 (DLX2), matrix metallopeptidase-13, tissue inhibitor of metalloproteinase-1, and tissue inhibitor of metalloproteinase-2 genes found that DF is more common in people of the African descent than among Caucasians and that the polymorphisms of TIMP1, DLX1, and DLX2 genes may be associated to their phenotypes (Kuchler et al., 2017).