We previously have shown that human SFSS features similar characteristics as its mouse counterpart, namely deficient cell cycle progression, downregulation of the cell cycle promoter FOXM1, upregulation of P21, metabolic insufficiency (persisting steatosis, hypoalbuminemia, hyperbilirubinemia), and an elevated mortality.2, 3 When examining YAP1 by immunohistochemistry, the protein displayed little expression in resting liver before hepatectomy, but was markedly upregulated (including nuclear expression) in regenerating human liver (Figure 5). The gene discussed is YAP1; the disease is steatosis.