SDHD and head and neck paraganglioma: Among the SDHD variant carriers, the risk of developing a head and neck paraganglioma was 17.5% (confidence interval [CI]: 15.9–19.1) after 5 years, 62.9% (CI: 33.5–92.3) after 10 years, and 82.4% (CI: 52.8–112.0) after 15 years (Fig. 2).