EXT1 and trichorhinophalangeal syndrome type II: Finally, four pathways are shared by the LC and the MPM groups: Fibroblast Growth Factor Receptor 4 (FGFR4) mutant receptor activation (R-HSA-1839128); Defective EXT2 causes exostoses 2 (R-HSA-3656253); Defective EXT1 causes exostoses 1, Trichorhinophalangeal syndrome type II (TRPS2) and CHDS (R-HSA-3656253); and Retinoid metabolism and transport (R-HSA-975634).