SDHB and gastrointestinal stromal tumor: As is well known, loss of function mutations in these genes are known to characterize the SDH-deficient GISTs lacking PDGFRA and KIT mutations in the context of Carney Triad or Carney–Stratakis syndrome or sporadic young adult KIT/PDGFRA wild-type GIST, thus mutations in any SDH gene are known to be mutually exclusive with KIT and PDGFRA [29,30].