FGFR3 and Osteochondroma: Moreover, Colvin et al previously found that some global Fgfr3 knockout (Fgfr3-/-) mice develop ectopic pockets of hypertrophic chondrocytes below growth plates [34], and Toydemir et al reported that osteochondroma has been detected in the long bones of several members of a family with CATSHL syndrome [31].