LGR6 and hydrops fetalis: HF stem cells are composed of different stem cell subpopulations, among them the Lgr5+ cells are located in secondary hair germ, Krt15+ cells (most co-express CD34+) are located in the bulge, and Lgr6+ cells are above the bulge and show similar capacity in regenerating the hair follicle and epidermis3, 4, 5.