NF1 and neoplasm: SDHB loss has been shown to be insufficient for tumour development in SDH-mouse models of PPGL (47), but the concomitant alteration of NF1 finally yielded SDH-like PPGLs, reinforcing the theory for a need of additional genetic events for tumour initiation and maintenance in SDHB PPGL, resulting in a lower penetrance of the mutations (48).