Mutations in the SDHD gene can lead to many different conditions. Sometimes, these mutations present themselves as paraganglioma or pheochromocytoma. These are commonly benign tumors that are often seen by the head (PGL) or in the case of pheochromocytoma (PCC) on the adrenal glands. These tumors cause hormones to be produced at abnormal rates and often lead to symptoms such as increased heart rate, blood pressure, and anxiety PGL tumors are reported as having a 31%-72% risk of becoming cancerous while PCC tumors have a 15%-31% risk of becoming cancerous. Tumors often develop around the age of 30 however, cases have been seen much younger. SDHD mutations can also present themselves in gastrointestinal stromal tumors (GIST). These tumors can develop anywhere along the gastrointestinal tract, including sites such as stomach, colon and small intestine. Most commonly, however, these tumors begin in the stomach. There is also thought that there is a possible association with breast cancer and thyroid cancer. It is recommended that those with a mutation in this gene begin screening between the ages of 5 and 10. These screening procedures include a blood pressure exam and physical every six to twelve month, MRI or CT of the head, neck, abdomen, thorax, and pelvis/, and a yearly urinary excretion exam. Mutations in the SDHD gene are inherited in an autosomal dominant manner, meaning each first degree relative (parent, child, and sibling) of an individual with this condition has a 50% chance of inheriting the disease causing mutation.