Hereditary Paraganglioma-Phaeochromocytoma Syndrome

Frequently Asked Questions (FAQs)

Q: Who is the best person in the family to undergo genetic testing?
A: In order to identify if a hereditary condition exists in a family, genetic testing is usually offered to the family member whose personal history is most suggestive of hereditary PGL/PCC syndrome (e.g., someone who presents with PGL/PCC symptoms at a young age).

It is usually not advisable to test someone without a history of cancer/tumours unless the condition has already been identified in the family.

The genetic test results of an asymptomatic individual may have limitations:

• If they were to receive a negative result, it may not mean that there is no hereditary cause of cancer/tumours in the family. The individual being tested may not have inherited it, but others in the family may have, or the faulty gene may not have been identified yet.
• The result is only useful to the asymptomatic person being tested and their children, but not to their parents, siblings and other seconddegree family members.
  

Once the faulty gene in the family is identified, genetic testing can be offered to other family members including those who do not have a tumour/cancer. This will help them understand if they have inherited the faulty gene change and if so, tailor their management to manage or reduce their risks.

Common Myths & Misconceptions

1. If test positive, it means that the cancer/tumour will recur.

   FALSE. The genetic test result cannot determine the likelihood of tumour/cancer recurrence or the presence of tumour/cancer. A positive result only confirms the diagnosis of hereditary PGL-PCC syndrome, which indicates an increased risk of getting tumour/cancer or a new tumour/cancer developing.
   
   

2. If I or my child tests positive, it means that my children/grandchildren will have it too.

   FALSE. If you or your child have a positive genetic test result for hereditary PGL/PCC where a faulty SDHx gene(s) is identified, it means each of your hildren/grandchildren has a 50% (1 in 2) chance of inheriting the same faulty gene(s).
   
   

3. If I have hereditary PGL/PCC, and my daughter looks a lot like me, she must have inherited the faulty gene(s) since I have it.

   FALSE. Genes that govern your appearance are different from the genes that determine the risk of hereditary PGL/PCC syndrome like any SDHx genes. All first-degree relatives (siblings, children and parents) have a 50% (1 in 2) chance of inheriting the faulty SDHx gene, regardless of whether they look like you or not.
   
   

4. I have two brothers, so one will inherit the faulty gene(s) and one will not, because there is a 50% chance.

   FALSE.Each first-degree relative (parents, siblings and children) has a 50% (1 in 2) chance of inheriting the faulty gene(s). The genetic test result of one sibling does not impact the chances for the other sibling.

Download the Hereditary Paraganglioma-Phaeochromocytoma Syndrome brochure.