Within 4 weeks of 4-OHT treatment (Figures 5A and 5B), Lgr6 KI/R26R-tdTomato/Ctnnb1lox(ex3)/+ mutant skin developed ectopic HFs from the SG and IFE and exhibited expansion of the upper portion of the HF (Figures 5C, 5D, 5H–5J, and 5L). This evidence concerns the gene LGR6 and Hand-foot syndrome.