SDHD and neoplasm: 58 tumor samples (55 PGL, including 45 head and neck PGL, 2 PCC, 1 GIST) were analysed in a study, and pathogenic variants in 50 patients (22 (13%) SDHB, 1 (3.2%) SDHC and 27 (57%) SDHD) were detected (24).