The gain-of-function mutant of Fgfr3 causes achondroplasia [51], Sox9 controls chondrocyte differentiation via Sox5 and Sox6 expression [52], and Ihh is a master gene of bone development under BMP control [53], [54], suggesting that Slc39a13 exerts a profound influence on genes crucial to chondrocyte differentiation. The gene discussed is SOX5; the disease is achondroplasia.