In family 1, 12 instances of SDHD gene mutation were detected, eight of which manifested as bilateral carotid body tumor (CBT) with one bilateral malignant CBT.
A patient with a history of carotid body paragangliomas and an aggressive form of kidney cancer was evaluated from a family with a germline SDHD mutation.
Tumorigenesis of NF1-associated pheochromocytomas remains unknown, as does tumor formation (i.e., carotid body tumor) in patients with germline mutations in SDHB, SDHC, and SDHD, genes that encode subunits of the mitochondrial complex II, the smallest complex in the respiratory chain.