If you are considering extending or starting a family, the TSA recommends speaking to a clinical geneticist or a genetic counsellor to discuss your options and any questions or concerns. The genetics team can give you advice on reproductive options, such as procedures to screen for TSC during pregnancy, IVF with pre-implantation genetic diagnosis (PGD), and sperm or egg donation.

The genetics team will aim to look into the risk of recurrence of TSC for a family, often by identifying the specific ‘spelling mistake’ that causes TSC in that individual, which will be in either of the genes called TSC1 and TSC2. If a change in the TSC1 or TSC2 gene is identified, this can be used for prenatal or pre-implantation testing.

It is likely that your TSC clinic can refer you to a genetics team, or you could ask for a referral through your GP.

About one in three people who live with TSC have inherited the condition from a parent who also lives with TSC. The other two in three people who live with TSC do so because of a spontaneous mutation in one of the genes that responsible for TSC.

If a parent lives with TSC, there is a 50% chance that their child will also inherit the condition. Therefore, many people who have parents, siblings or children who live with TSC, have an assessment or genetic test to see if they also have TSC.

In around 2% of TSC cases, parents who do not live with TSC will go on to have more than one child with TSC. This is called ‘mosaicism’ and occurs because the genetic mutation that leads to TSC is found in cells in only the sperm of the man or eggs of the woman. In cases of mosaicism the likelihood of a child inheriting TSC might not be 50%. Prenatal and preimplantation genetic diagnosis testing usually cannot be offered in cases of mosaicism.

You can read more about TSC and genetics here.

TSC is a genetic condition, meaning that it is caused by a ‘spelling mistake’ in a person’s genes. If one parent has TSC, there is a 50% chance in every pregnancy that the baby will inherit TSC.

This does not mean that if your first child has TSC, a second child will definitely not have it (or the other way around). Every pregnancy has a 50% chance of the child having TSC or not having TSC, if you or your partner have TSC.

It is important to remember that TSC affects everyone differently. The extent to which TSC affects a parent or any other family member may be different from a child with TSC. In other words, if you are a parent who has TSC, the way TSC affects you may be different from how TSC will impact your child if they inherit the condition.

Many women with TSC have a normal and healthy pregnancy. However, there are some potential issues that women who live with TSC and are going through pregnancy need to be aware of.

Women who live with TSC and have kidney issues such as kidney angiomyolipomas (AMLs) or lung issues such as lymphangioleiomyomatosis (LAM) may find that these conditions worsen during pregnancy. Therefore, it is important to talk to your clinicians during pregnancy planning or as soon as possible after becoming pregnant, to see if any extra measures need to be put in place.

Some anti-epileptic drugs can also affect the development of an unborn baby, and some are not recommended if breastfeeding. However, it is important that you do not stop taking any medication without talking to your doctor first.

You can read more about LAM and pregnancy from LAM Action.

If the gene responsible for TSC is identified in one of the parents through genetic testing, prenatal testing on the baby can be performed during pregnancy to find out whether the baby will also have TSC. Some families find testing for TSC in a child during pregnancy (called ‘prenatal testing’) useful, both from a practical and an emotional perspective.

Prenatal testing can provide information on whether a baby has TSC but cannot be used to identify how TSC will impact on the child. In other words, it will still be unknown how severely affected the child will be and whether they will have problems such as epilepsy, kidney problems, learning difficulties (or other issues connected with TSC) or not.

The techniques used for prenatal testing carry a very small risk of miscarriage. Prenatal testing may indicate that the baby is predicted to be affected by TSC and families may choose to not continue the pregnancy. This difficult choice is down to individual families and the clinical circumstances surrounding their pregnancies.

Ultrasound scans can also be used to identify signs of TSC in an unborn baby, such as heart rhabdomyomas. However, ultrasound scans can only be used to identify possible signs of TSC and cannot show that a child definitely does not have the condition.

Preimplantation genetic diagnosis (PGD) is another option for family planning, if the gene responsible for TSC is identified in one of the parents through genetic testing. PGD is used to identify a genetic change in an embryo created through in vitro fertilisation (IVF), before implanting the embryo into the uterus. The purpose is to identify an unaffected embryo for implantation, reducing the risk of a child having a genetic condition like TSC.

Egg and sperm donation is an option for many families for a range of reasons, including if a parent is likely to pass on a genetic condition, like TSC. The process involves using eggs and/or sperm cells that have been donated from other people, instead of those from the parent(s) of the child.

You can find out more about egg/sperm donation including fertility treatment options through the UK Human Fertilisation and Embryology Authority.

Surrogacy is another reproductive option that might be an option for people in the TSC community who are planning a family. Surrogacy is an arrangement, often supported by a legal agreement, where a woman agrees to carry a pregnancy and give birth to a child for another person(s), who then become the child’s parent(s) after birth. The woman giving birth is known as the ‘surrogate’.

The woman who will give birth (the surrogate) might use her own eggs, or she might be implanted with someone else’s fertilised egg.

From a TSC perspective, surrogacy may be an option that individuals and couples consider if it is the woman who has been identified as carrying the TSC gene.

You can find out more about surrogacy in the UK through the UK Government website and Surrogacy UK.

Adoption is the process by which a child or children who cannot be brought up by their birth family become permanent, legal members of a new family. Adopters become legal parents with the same rights and responsibilities as they would have with a biological child.

People choose to adopt a child for a wide range of reasons. You can find out more about adoption in the UK through the UK Government website and the charity Adoption UK.

Whatever your decisions around family planning, remember that the TSA is here for you. You can contact the TSA Support Line to get through to a friendly and listening ear, who can help to go through the above steps and options with you.