Foreword: although the following article discusses family planning options for VHL syndrome, the same processes and treatments also apply to HLRCC (FH gene) and BHD (FLCN gene). Please consult a doctor before making any decisions around family planning.
Family planning
One natural question somebody diagnosed with VHL may ask is “Can I have children?” – the answer is YES – however there are a few things you may want to consider before getting started.
Firstly, von Hippel-Lindau syndrome is an autosomal dominant condition; that means that children of a parent with VHL have a 50% (half) chance of inheriting the syndrome themselves. It’s important to keep in mind that VHL can differ in severity and presentation not only between families but within families too. That is to say, even siblings both affected with VHL can have wildly different experiences with the disease.
Pregnancy in VHL
Naturally, many women affected with VHL want to know how their disease may be affected by pregnancy. There is currently no clear answer as to whether pregnancy impacts tumour growth – and it’s very important that you discuss your individual situation with your doctors. The studies that have been conducted observing pregnant women with VHL show mixed results; some women see increased tumour growth, whilst some saw no change.
Pregnant women must be monitored closely by their obstetrician, as VHL tumour symptoms may be masked by symptoms that are normal in pregnancy, for example: vomiting, headaches and increased blood pressure. Despite the need for increased monitoring, the majority of women with VHL go on to have normal pregnancies and a normal birth.
Surrogacy
Some women; perhaps those who have carried a pregnancy previously and developed complications, or those who have complex and active tumours may wish to pursue surrogacy. Surrogacy is usually only used in cases where your VHL makes it impossible or dangerous to get pregnant and give birth. It’s important to know many women are able to have normal and healthy pregnancies. Your doctors will be able to advise if surrogacy is a suitable option for you and your family.
CVS testing and amniocentesis
Couples who conceive naturally have the option to undertake CVS (chorionic villus sampling) or amniocentesis. CVS is a procedure carried out between the 11th and 14th weeks of pregnancy, in which a sample of the placenta is taken for genetic testing. As the placenta and the baby both come from the same cells, if the placenta carries the mutated VHL gene, the baby will also be affected by VHL syndrome. One alternative test is amniocentesis, a procedure carried out between the 15th and 18th week of pregnancy, in which a small sample of cells is taken from the amniotic fluid. The sample, containing cells from the baby, is then screened for the faulty VHL gene. The results of these tests can help you to make informed decisions regarding the continuation of the pregnancy.
More information available:
https://www.nhs.uk/conditions/chorionic-villus-sampling-cvs/
https://www.nhs.uk/conditions/amniocentesis/
PGT-M
One way to ensure that a child of a VHL parent does not inherit VHL syndrome, is to undergo pre-implantation genetic testing. Pre-implantation genetic testing for monogenic disorders (PGT-M, previously known as pre-implantation diagnosis, PGD) is a fertility treatment in which embryos are created via assisted reproductive techniques (ART) such as IVF or ISCI, which are then screened to analyse which embryos carry the inherited disease causing variation.
How does it work?
You will usually be referred from your GP or clinical genetics team. Once a couple decides to undergo PGT-M, and have passed all the checks, the egg retrieval process will begin. This usually involves a series of injections to encourage eggs to grow; once ready, the eggs will be extracted and turned into embryos in the lab. Once the embryos have been created, one cell from each is taken for testing. After the results are available, an unaffected embryo will then be transplanted into the uterus. If successful, the resulting baby will not carry the faulty VHL gene and will therefore not be at risk of developing VHL syndrome.
(https://www.invitra.com/en/about-the-pgd-process/)
Although specific restrictions on who can or can’t have the treatment vary by location – VHL is an approved condition for PGT-M (OMIM #193300), and has been utilised for many families affected with VHL in the UK. The process can be long and intimidating, and as with any medical procedure there is no guarantee of success; however PGT-M is a well established technology that has brought peace of mind to many families, and helped thousands of babies to be born. Your local genetics team will be best placed to answer any specific questions.
More information available:
https://www.nhs.uk/conditions/ivf/
FAQs
If I have one child with VHL, is there an increased/decreased risk that my next child will also have the disease?
No, for every child that is conceived without PGT-M, there is a 50% chance of them inheriting the disorder. This chance remains the same regardless of how many children you have, or if the baby is a boy or girl.
Is PGT-M free on the NHS?
All fertility treatment funding varies by location. PGT-M can be available to couples free of charge through the NHS if they meet the strict eligibility criteria. For example, in general, the treatment must begin before a woman turns 40, be a non-smoker, and her BMI should be between 19 and 30. Couples who already have a child that does not have VHL syndrome (an unaffected child) are not currently eligible for PGT-M on the NHS.
Does PGT-M still work if I am a man who has VHL syndrome?
Yes. Regardless of sex, any child of a biological parent who has VHL syndrome will have a half chance of inheriting the disorder themselves. In this case, your partner will need to undergo the egg retrieval and implantation process in order to create embryos for PGT-M testing.
Do I have to do PGT-M to have a child if I have VHL?
No, there is no “correct” way to have a family. Some choose to conceive naturally, some may choose adoption, surrogacy, or some may choose to use a sperm or egg donor. Your genetics team should be able to offer you tailored advice on the options for you and your family.
I have been diagnosed with VHL syndrome, but they have not found a gene variant causing the disease. Am I eligible for PGT-M?
As a general rule, only registered “pathogenic” or “likely pathogenic” (disease causing) variants are eligible for PGT-M. Variants of Unknown Significance (VUS) do not fall under the criteria for embryo testing.
