This information explains how having a mutation in the SDHD gene may affect you and your family.
In this resource, the word “family” means people related to you by blood. They’re not related to you through marriage or adoption. We also call these family members your blood relatives.
Your SDHD gene normally helps prevent tumors from developing. A mutation in this gene causes it to stop working like it should.
It is important to understand that having a mutation in this gene does not mean you will definitely develop cancer. It means that you have an increased risk of developing certain types of cancers. The type of cancer can vary among people who have mutations in this gene, even within the same family.
What is my cancer risk if I have an SDHD mutation?
If you have a mutation in the SDHD gene, this means you have a condition called hereditary paraganglioma-pheochromocytoma (PGL/PCC) syndrome.
SDHD mutations increase your risk for certain types of tumors, including paragangliomas and pheochromocytomas, which are typically benign tumors that affect the neuroendocrine system.
SDHD mutations may also increase your risk for other cancers, but this is less common. Some examples of less common cancers linked to SDHD are:
- GISTs (gastrointestinal stromal tumors).
- Kidney cancer.
The risk of developing these less common cancers are not well established.
As we learn more about these mutations, we may learn they increase the risk for other types of cancers. Your genetic counselor will give you more information about your cancer risk if you have a mutation.
What can I do about my cancer risk if I have an SDHD mutation?
Your genetic counselor will review your results. They will talk with you about what cancer your mutation is linked to. As we research these mutations, we may learn they raise the risk for other types of cancers.
Your genetic counselor will also review your personal and family history of cancer and give you cancer screening recommendations. They may recommend you start having cancer screenings at a younger age or have them more often than most people. They may also suggest you get specialized screenings to help find cancer as early as possible.
Some examples of these cancer screenings include:
- Magnetic resonance imaging (MRI) scans or computed tomography (CT) scans of the base of the skull, neck, and of the whole body.
- Physical exam with extra attention to blood pressure and any issues involving the abdomen (belly), chest, or neck areas.
- Blood tests and urine (pee) samples.
- Ultrasound or MRIs of your abdomen.
Some of these screenings will happen once a year. Others may happen more or less often. Your genetic counselor will talk with you about screening recommendations and how often you should get them. They will also talk with you about whether there are any other screening or prevention options that may be right for you.
What does an SDHD mutation mean for my blood relatives?
If you have a mutation, your biological parents, siblings, and children each have a 50% chance of having the same mutation. Your distant family members may also be at risk for having the same mutation.
SDHD mutations are known to show a parent-of-origin effect. This means that your cancer risk depends on which parent you inherited the mutation from. Even though a mutation in SDHD can be passed on to a child from either parent, mutations in the SDHD gene are associated with a more significant risk of disease when inherited from the father.
Because of this, we recommend screening when the SDHD mutation is inherited from your father, or if the parent-of-origin is unknown. Screening may also be considered when the SDHD mutation is inherited from your mother.
Your genetic counselor will review your family history and talk with you about whether they recommend genetic testing for your blood relatives.
What does this mean for family planning?
If you have an SDHD mutation and plan to have children, there are options to prevent your children from inheriting the mutation. You may want to consider discussing these options with your reproductive partner and a genetic counselor.
What happens if I do not have a mutation?
If you do not have a mutation or if we find a variant of uncertain significance (VUS), your genetic counselor will review your personal and family history of cancer. They’ll talk with you about the general cancer screening guidelines you should follow.
A VUS is a change in a gene, but we don’t yet know if it is linked with a higher risk for cancer. Most VUS are eventually found to be normal changes that do not affect your health.