When Mary and Michael Willams learned their first child Daisy had epilepsy, they were terrified they would lose her during one of her violent seizures - but their nightmare was just beginning.

Their next child, Danielle, also developed epilepsy, and so did their son, David. Now they are frantically watching for signs of the condition in their as-yet unaffected son George.

"Daisy was normal until she was around five and then one day I was watching her run along the path to school when she suddenly stopped and dropped to the floor," said Mrs Williams, 40, of Grove.

"I ran over to her. I was terrified. I thought she was dead. But she was shaking violently and I realised she was having some kind of fit.

"I had worked with people with epilepsy in the past, and my mum and sister had also had it," she said.

"But we were back and forth to the doctor for two years before it was finally diagnosed. She was at the hospital having an ECG when she had another seizure."

In addition to seizures, Daisy, who is now 13, also suffers sudden bouts of extreme agitation because of her epilepsy.

"It's like she develops super-human strength," said Mrs Williams. "I have seen her lift up a hospital bed and shake it and once she tried to jump out of a window and two paramedics had to hold her down.

"It's terrible and really worrying because as well as the thought she could be hurt during one of her fits, she has these times when she loses control completely."

The Williams were still struggling to come to terms with their oldest daughter's medical problems when Danielle, now 10, started to suffer blackouts.

"Danielle's epilepsy doesn't give her fits like Daisy, but it does make her pass out," Mrs Williams said.

"They're not as violent as Daisy's seizures, but they're just as sudden and just as frightening, because she could be doing anything when she passes out - such as running or crossing the road.

"The blackouts also have no pattern to them," she added. "She could have two or three a week, then not have any for months."

Then David, now nine, started suffering blackouts at just 18 months.

"I did blame myself for a while," said Mrs Willams.

"I asked the doctor if this was hereditary and if I had passed it on to the children from my side of the family.

"Some doctors say there is a link and some say there isn't.

"The children have lost friends because of their epilepsy - it is frightening for other children to see their 'attacks'.

"She is now at a special needs school however, and since being around children with terrible epilepsy, she realises that in some ways she could be a lot worse.

"David was on medication for a while, but was taken off it and seemed fine.

"But recently he started suffering the blackouts and pains in his legs again, so he is back on the medication.

"We have been hoping that the children will grow out of their epilepsy, like some other children do. But Daisy is 13 now.

"Their condition also affects everything we do as we have to keep such a close eye on them.

"They have to have their medicine or tablets twice a day and they all want to be out playing, but we only allow them to do that together, so that if anything happens to one of them, another can stay with that child and the other can raise the alarm.

"We go to holiday camps so they're always close by to us while they're playing or swimming and even a car journey can causes problems for Daisy as the light dazzling the windows can trigger a fit."

Mr and Mrs Williams are now keeping their fingers crossed that their youngest son, George, seven, is not affected.

"He seems fine and hopefully he'll stay that way. It's not just the way their lives are being affected as children, I worry about how it will affect them as adults. They may not be able to drive and do other things people take for granted."

Daisy, 13, said epilepsy sometimes made her feel different.

"I am okay when I am taking my tablets. but I have to be careful not to forget then," she said. "I don't really know when something is going to happen, it's just afterwards when I wake up that my mum and dad tell me about it.

"Afterwards I sometimes feel tired and have a headache.

"It helps a bit to go to school with other children with it (epilepsy), but I would just like it to go."