Two previous studies [24,25] investigating the role of the SDHD gene in canine endocrine neoplasias demonstrated that a synonymous mutation (c.365A>G, p.Lys122Arg) in dogs is associated with the presence of paragangliomas (PGL) and pheochromocytomas (PCs). Here, SDHD is linked to hereditary pheochromocytoma-paraganglioma.