PDGFRA and hydrops fetalis: In fact, they demonstrated that Hh-signaling in the reticular fibroblast lineage promotes wound closure, possibly via increased angiogenesis and the expansion of PDGFRα+ wound bed fibroblasts, while Hh-signaling in the papillary fibroblast lineage is essential for the expression of HF morphogenesis-associated genes and de novo HF formation within the healing wound (Frech et al., 2022).