SDHB and gastrointestinal stromal tumor: Succinate dehydrogenase B-deficiency in PGL has generally been connected to mutations in SDHB, SDHC, or SDHD (van Nederveen et al., 2009; Gill et al., 2010a), and, as previously noted, germline SDHB-D mutations were identified in most of the CSS GIST cases (Pasini et al., 2008).