SDHD and neoplasm: The overall median follow-up period of the subjects without a tumor was 5.54 years (1.08–17.7); 4.09 years (3.00–5.17) for SDHA, 5.92 years (2.33–13.33) for SDHB, and 4.83 years (1.08–17.17) for SDHD variant carriers.