We conclude that heterozygous loss-of-function mutations in PTPN11 are a frequent cause of MC , that lesions in patients with MC appear to arise following a `` second hit , '' that MC may be locus heterogeneous since 1 familial and 5 sporadically occurring cases lacked obvious disease-causing PTPN11 mutations , and that PTPN11 mutations are not a common cause of Ollier disease or Maffucci
O O O O O O O B-GeneOrGeneProduct O O O O O B-DiseaseOrPhenotypicFeature O O O O B-OrganismTaxon O B-DiseaseOrPhenotypicFeature O O O O O O O O O B-DiseaseOrPhenotypicFeature O O O O O O O O O O O O O O O B-GeneOrGeneProduct O O O O B-GeneOrGeneProduct O O O O O O O B-DiseaseOrPhenotypicFeature I-DiseaseOrPhenotypicFeature O B-DiseaseOrPhenotypicFeature I-DiseaseOrPhenotypicFeature O