TRPS type 2 or Langer-Giedion syndrome (OMIM #150230) involves TPRS1, RAD21 and EXT1, and the facial phenotype is mainly determined by loss of TRPS1, whereas the bony abnormalities arise from the loss of EXT1 (Maas et al. 2015). The gene discussed is EXT1; the disease is trichorhinophalangeal syndrome type II.