Von Hippel-Lindau Syndrome

Frequently Asked Questions (FAQs)

Q: Who is the best person in the family to undergo genetic testing?
A: Genetic testing is initially recommended for a family member whose cancer diagnosis/medical history is most suggestive of a hereditary cause (e.g., young or unusual cancer/tumours). It is usually not advisable to test someone without a history of cancer, tumours or clinical features suggestive of VHL.

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/clinical features 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 extended 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 cancer) to understand if they have inherited the faulty gene and if so, tailor their management to manage or reduce their risks.

Common Myths & Misconceptions

1. If my genetic test result is positive, it means that I have or will have tumours/cancer, or my tumours/cancer will recur.

   FALSE. The genetic test result cannot determine the likelihood of tumour/cancer recurrence or the presence of a tumour/cancer. A positive result only indicates an increased risk of developing a tumour/cancer or a new tumour/cancer developing.
   
   

2. If I test positive, it means that my children will also have VHL.

   FALSE. If you have a positive genetic test result where a faulty gene(s) is identified confirming VHL, it means each of your children has a 50% (1 in 2) chance of inheriting the same faulty gene(s).
   
   Your grandchildren would only be at risk if their parent (i.e., your child) has inherited the faulty VHL gene. The faulty VHL gene does not skip generations.
   
   Even if an individual inherits the faulty gene, it does not guarantee that they will develop tumours/cancer associated with VHL. They only have an increased risk as compared to the general population.
   
   

3. My daughter looks a lot like me, so 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 VHL syndrome like VHL. All firstdegree relatives (siblings, children, parents) have a 50% (1 in 2) chance of inheriting the faulty VHL gene.
   
   

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, children) has a 50% (1 in 2) chance of inheriting the faulty gene(s). The genetic test result of one sibling does not determine the chances of the other sibling.

Download the Von Hippel-Lindau Syndrome brochure.