VHL and Dowling-Degos disease 1: Chondrocyte hypertrophy plays an important role in endochondral ossification during skeletal development.24 Notably, studies report that chondrocyte hypertrophy induces the initiation and progression of EP cartilage degeneration during DDD development.25 To explore the mechanism of the accelerated DDD in VHL-conditional-knockout mice, the expression levels of proteins related to chondrocyte hypertrophy were explored by IHC staining.