This finding is consistent with our previously published targeted mouse models of chondrodysplasia (supplementary material Table S1) and is a well-documented clinical feature in individuals with PSACH, MED and MCDS (Briggs and Chapman, 2002; Lachman et al., 1988; Leighton et al., 2007; Piróg-Garcia et al., 2007; Rajpar et al., 2009; Suleman et al., 2012). Here, COMP is linked to chondrodysplasia.