If a person is living with TSC, they were born with it. This is because TSC happens when a person’s ‘genes’ (the things that make the body grow) don’t act like they are meant to. You are not able to ‘catch’ TSC, like you can with a cold or flu.
A person living with TSC might still not be told that they have TSC until you are older. Possibly even when they are a grown-up. This is because the condition might not have been found until then or was not causing any problems.
When a condition happens because of a person’s genes, it is described as a ‘genetic disorder’. TSC is a genetic disorder.
What are genes?
Genes are what we are made out of. Genes tell the body how it should grow. Everyone has lots of genes. Every gene is responsible for different things, like eye colour or how tall you might be. The genes that make up our bodies come from your parents.
What is a genetic disorder?
Sometimes, a gene does not do what we expect and it change. This happens naturally. A change to a gene might mean that it does not tell the body how to grow as it normally would.
Changes to different genes mean that different things might happen. This is how genetic disorders, like TSC, happen.
TSC happens when two genes, called TSC1 and TSC2, do not do what we might expect.
The genes that make up our bodies come from our parents. If a person’s mum or dad has TSC, it might mean that their son or daughter will also have it. However, a person might also live with TSC even if their mum or dad doesn’t have the condition.
TSC from mum or dad
Around one in every three people who live with TSC has it because their mum or dad gave them one of the TSC genes with unexpected changes to it. This is called ‘Dominant inheritance’.
If a mum or dad is living with TSC, there is a 50% change that a baby they are having will also live with TSC. It does not matter who out of mum or dad lives with TSC, or if the baby is a boy or a girl.
TSC when mum and dad do not have it
Some people who live with TSC have it but their mum or dad don’t. This means that the TSC genes unexpectedly changed but were not given to the child by mum or dad. Usually, if this happens it is only in one of the babies that the mum and dad have.
It does not happen a lot, but a mum and dad who do not have TSC might have more than one baby who lives with the condition. This is because the TSC genes with unexpected changes are not everywhere in the mum or dad’s body, so it does not affect them as much. This is called ‘Mosaicism’ and it is hard to test a mum or dad to see if they have it.