Of those with germline SDHB mutation and SDHAF3 variant (n = 7), three (43%) have developed pheochromocytomas or paragangliomas (S11_1, S11_2 and S11_3); while two (25%) of those with germline SDHB mutation and wild-type SDHAF3 (n = 8) have developed paragangliomas (p = 0.47, Chi-squared test). This evidence concerns the gene SDHB and paraganglioma.