In about 60 % of cases TCS is not inherited from parents but is caused by a genetic mutation, with no apparent cause (sporadic). This is what happened in my case, neither of my parents have TCS.

It can however be passed on; there is a 50% chance a person with TCS will pass it on to their children.

If the gene is inherited it will result in an affected individual although the severity of the symptoms and physical characteristics can be extremely varied. The severity of the parents does not necessarily reflect the severity of the children.

Parents who do not have TCS but have a child with it are extremely unlikely to have a second affected child. The chances of the next child being born with TCS are only very slightly higher than those of any other couple.