Genetic Testing – a sister’s experience

I used genetic testing because my sister had TSC and I wanted to start a family of my own. Testing gave myself and my husband the re-assurance that we needed that our children wouldn’t have a higher risk of Tuberous Sclerosis.

My sister was severely affected with TSC and also Polycystic Kidney Disease (PKD). It had been confirmed that this was due to a large deletion across the TSC2 and PKD1 genes as a part of setting up the TSC genetic testing in Sydney. Neither of my parents tested positive for the same mutation.

The possibility that played in the back of my mind was that one of my parents was mosaic for a TSC mutation and that they had passed on this mutation to both my sister and I. I knew the likelihood of this was really small, plus I showed no clinical signs of TSC. But I was still anxious to rule TSC out before we had any children. So we made an appointment to see a genetic counsellor.

My husband and I both found the appointment really informative and useful. The counsellor took a full medical history from both of our families and explained the genetics of TSC really clearly which was especially helpful for my husband. I went upstairs for a simple blood test.

A couple of weeks later the results were back. As expected they were negative, meaning that I did not carry the TSC2/PKD1 mutation that my sister had. This meant that I was as likely to have a child with TSC as anyone without a TSC affected family member. Since then we have had two lovely boys, neither of which have TSC.

I had always felt silly for wanting the genetic test – I knew that it was really unlikely that my sister was anything but a ‘sporadic mutation’. However it was very helpful when my son had a number of focal seizures when he was 18 months old. I was able to confidently say that I knew it was a seizure after seeing my own sister have many of them. Then I also explained that despite this family history that I was confident that he did not have TSC. Thank you to the members of the ATSS facebook discussion group for their advice about how to get an 18 month old to sit still for an EEG!