Heterozygous loss-of-function germline variants in succinate dehydrogenase genes (SDHA, SDHB, SDHC, SDHD, and assembly factor SDHAF2) are responsible for a number of tumor diseases, foremostly paragangliomas of the sympathetic or parasympathetic nervous system and pheochromocytomas (together referred to as PPGL). This evidence concerns the gene SDHB and neoplasm.