part of part of capable of capable of expresses chondrocyte hypertrophic chondrocyte A chondrocyte that is part of the hypertrophic cartilage zone. This cell is significantly enlarged and characterised by high expression of type X collagen (COL10A1) in both humans and mice. It actively coordinates endochondral ossification by mineralising the extracellular matrix, attracting blood vessels via angiogenic signalling, and mediating the transition from cartilage to bone - often by transdifferentiating into an osteoblast rather than undergoing apoptosis. ZFA:0009313 Despite historical descriptions as 'terminally differentiated,' hypertrophic chondrocytes survive and transdifferentiate into osteoblasts. Genetic lineage tracing shows that hypertrophic chondrocytes do not simply undergo apoptosis but cross the cartilage–bone boundary, dedifferentiate into skeletal stem/progenitor cells, and then redifferentiate into osteoblasts and osteocytes. Single-cell RNA-seq further indicates that these chondrocyte-derived SSPCs are a major source of trabecular osteoblasts and marrow adipocytes. bone cell endochondral ossification Homo sapiens collagen alpha-1(X) chain hypertrophic cartilage zone