Most people with VHL inherit this genetic mutation from a parent. However, approximately 20% of people with VHL have a new VHL mutation not passed down from a parent.
The de novo (new) mutation occurred in the germ cell (sperm or egg) or the young embryo before a process called cell differentiation. As the embryo grew, this new mutation replicated over and over again. Thus this person will have a mutation in the VHL gene in every cell of their body which can be identified via a genetic test. Although there is no family history of VHL, the person will still have a 50% chance of passing it on to their children.*
Being the first person in a family to have VHL comes with unique challenges. De novo patients may not know where to find a team of doctors who have a lot of experience in managing the complex disease that is VHL. Furthermore, their family and other caregivers may not know how to holistically support the VHL patient with this new diagnosis. It can feel very isolating—sometimes very scary– when a person is the only one s/he knows that needs scans, surgeries, and other treatments.
Know that VHL Alliance is here to support all patients and caregivers. In addition to helping connect patients to outstanding clinical care, the VHL Alliance also has a lot of support resources for patients and caregivers to support them in living a flourishing life with VHL. Questions that are not addressed on this website or in the VHL Handbook may be directed toward the VHL Alliance.
*What is mosaicism?
There are some VHL patients with a “mosaic” case of VHL, meaning they only have the VHL mutation in some organs. This can make it more challenging to identify the VHL mutation using a standard genetic test. Mosaicism occurs when the new mutation occurs a bit later in the embryo’s development during the process of cell differentiation. The dominant inheritance pattern only applies to people with mosaicism if they have the VHL mutation in their germ cells.