SDHD and neoplasm: There are others tumor risks associated with SDH complex gene mutations, including gastrointestinal stromal tumors (GISTs) in Carney-Stratakis syndrome (dyad of PGL/PCC and GIST related to SDHB , SDHC , and SDHD mutations) and renal cell carcinoma, which has been described in some families with SDHB mutations ( 17 , 18 ).