SDHD and head and neck paraganglioma: Germline mutations in any of the four genes that encode SDH subunits (SDHA, SDHB, SDHC, SDHD) may be associated with dSDH tumour types (e.g. paraganglioma, phaeochromocytoma, head and neck paraganglioma, RCC and wild-type gastrointestinal stromal tumours (GIST)) but RCC has been particularly associated with germline SDHB mutations (though the lifetime risk of RCC is likely less than 10%) [27, 28].