Sean Daly is 19 and has had epilepsy since he was four years old. Up until that age he was a happy, healthy little boy, developing at the normal pace and hitting all his milestones.

When the epilepsy started, he was having between 40 and 50 seizures per day and instead of progressing like most little boys, his development stopped and he started losing skills he had gained in his first four years.

One of the hardest things, his mother Colette says, was the fact that they could not get a correct diagnosis for Sean and were told he had intractable epilepsy- or unexplained epilepsy.

This left the family distraught and in a state of limbo, as his parents wondered what might have caused the epilepsy.

It wasn’t until last year that through a genomic sequencing project that he was involved in –it was discovered that he has a rare, non-inherited mutation of the CHD2 gene. This brought great relief to Sean’s parents and siblings, who up till that point did not know if it would affect their other children or possible grandchildren. Getting the diagnosis has given them answers and hope, Colette says.

She tells us Sean’s story:

“Sean was born very typically and developed very typically and wonderfully for the first four years of his life and met all his milestones, doing everything they way he should, so we had no medical worries at all. Unfortunately at that age he started to have multiple seizures. It was very difficult not to get a diagnosis and we spent 14 years questioning and searching and wondering and agonising, was it something we did. We kept asking the doctors and neurologist but they couldn’t give us answers. Things were so severe, he lost all of his skills that he had developed; pre-school writing and words and after a few years of horrific seizures he started to lose all of that. He was going backwards and that is the most painful thing for any parent.

“In that time Sean has been on 17 different epileptic medications in lots of different combinations. They found a benign brain tumour and removed that to see if it would make a difference but it made no difference. We tried lots of diets and steroid treatments, he has done everything.

“Three years ago a professor, Tracy Dixon Salazar, gave a talk in RCSI about genetics. Her own daughter Savannah, who has epilepsy, inspired her to become a geneticist.

“Savannah had an almost identical medical history to Sean and after years of research she discovered her daughter had a genetic glitch on one of her genes and that’s what caused all the seizures. I thought to myself; this has never been looked at except for basic genetic hereditary tests.  

“Sean then got signed up for a project called the Lighthouse, which is a strand of Future Neuro. They were looking for 60 candidates with severe epilepsy, with accompanying intellectual disabilities and they did genomic sequencing, an in-depth look at each person. About a year ago we got called in to tell us that he had a very rare, non-inherited de novo mutation of the CHD2 gene.

“It was unbelievable and such a profound sentence for us to hear, as they were finally giving us a diagnosis after 14 years of waiting. You always think, it was the time he fell off the trike, the time he fell off the bed and you agonise over everything. You torture yourself. But it’s a genetic glitch and nothing that could have been done about it, it started in the womb.

“Our first question was, can we cure it, but I knew from lots of my own research that it couldn’t be fixed. His seizures are symptoms of this glitch. There is amazing work being done in this field, and once they know the origins, they can be better equipped in saying which medication is most likely to work. At the moment, the medicine is like a lottery, you just give everything a try. The aspiration is that they can personalise your medication to find the best treatment but it hasn’t reached that stage for us yet.

“Sean is a good bit better now than he was. Previously he would have spent 60% of his year in hospital, and was an acutely unwell child. We stay away from hospitals now, other than for scheduled appointments and the seizures are much better controlled. He is down to maybe 3 seizures a week, which is a lot more manageable than it was. He is classed as special needs and is in an adult service now too.  He is a very strong, courageous young man, and is full of joy.

“It is my hope that they can gather data from other families worldwide with the same thing as Sean and we’ll get a much better picture of how to deal with it, so that they can tailor make treatments.

“Getting a diagnosis can’t be underestimated and I know it’s not a cure but it’s a major breakthrough. I gave a talk in RCSI a while ago and it was about hope. I wanted to inspire researchers- they need to hear the human stories behind the science and to be reminded of the immense impact they have on people’s lives, not only the patient but the family too.”

Make sure to go to this article if you are interested in reading about personalised medicine!