SDHB and neoplasm: By Kaplan-Meier analysis, the penetrance (cumulative risk of clinically apparent tumours) in <i>SDHB</i> and (paternally inherited) <i>SDHD</i> mutation-positive non-probands (n=371/67 with detailed clinical information) by age 60 years was 21.8% (95% CI 15.2% to 27.9%) and 43.2% (95% CI 25.4% to 56.7%), respectively.