Few genes were upregulated in dogs with CIE, including those involved in extracellular matrix degradation (matrix metallopeptidases 1, 3, and 13), inflammation (TNF, IL-8, peroxisome proliferator-activated receptor-γ, and S100 calcium-binding protein G), iron transport (solute carrier family 40 member 1), and immunity (CD96 and carcinoembryonic antigen-related cell adhesion molecule [CEACAM]) (88). The gene discussed is MMP1; the disease is congenital non-bullous ichthyosiform erythroderma.