This hypothesis is supported by evidence showing that the inhibitors of destructive enzymes are decreased in keratoconus corneas; they are alpha one (α1 proteinase inhibitor, alpha two (α2) macroglobulin, and tissue inhibitor metalloproteinase one (TIMP-1); the latter of which can inhibit cell apoptosis [3,20,24,25]. This evidence concerns the gene TIMP1 and keratoconus.