Our results suggest that PTPN11 and other members of the RAS/MAPK pathway should be examined in related and as yet unexplained Mendelian phenotypes such as Ollier's disease, Mafucci syndrome (OMIM 166000) and the trichorhinophalangeal syndrome type II (OMIM150230). This evidence concerns the gene PTPN11 and trichorhinophalangeal syndrome type II.