SHH and androgenetic alopecia: Finally, based on the increase in wool and active hair-follicle density in FGF5 KO sheep, we first mapped out the main mechanism of FGF5 function in anagen, including FGF5, FGFR1, androgen, AR, Wnt/β-catenin, c-MYC and KRTs, and Shh/GLI2 (Fig. 5), which helps to further understand the role of FGF5 gene, and provide a treatment for androgen alopecia.