We thought Minecraft was making our son ill - but the truth was much worse: Parents' agony as nine-year-old boy is told his 'next seizure could be his last' after being diagnosed with one of the world's rarest disease

A nine-year-old boy diagnosed with an extraordinarily rare genetic illness has been told his next seizure could be his last.

William Howard was originally told by doctors his bizarre symptom — a twitch in his right leg — could be down to 'stress' from playing Minecraft. 

But after 'endless' medical investigations, tests revealed that mitochondrial disease was actually to blame for his sudden and random twitching, which would make him fall over repeatedly. 

William is one of 10 people in the world who have his particular variation, his parents claim.

Simon, 45, and Mihaela, 43, from Swindon, say he went from a normal, healthy little boy to paralysed by seizures seemingly overnight.

William Howard, nine, (pictured) was told by doctors his initial symptom, a twitch in his right leg, could be down to stress from playing Minecraft

After 'endless' medical investigations, an MRI confirmed he has mitochondrial disease, which causes cells to not produce enough energy. His parents, Simon, 45, (left) and Mihaela, 43, (right) say he went from a normal, healthy little boy to paralysed by seizures, seemingly overnight

Ms Howard, a former nurse, said: 'Doctors have told us to prepare for the worst. One more seizure could be it for William. We're terrified but he's a fighter.

'It's a reason to get out of bed in the morning, because it's one more day with William.

'I'll check on him and see he's sleeping in his bed, and in that moment I think, we've got at least one more day together.'

William's parents first noticed his right leg started 'drooping' when he tried to walk and after a while they became concerned. 

Mr Howard, a chef manager, called 111 and was told to take him to the GP the next day.

However, he drove him to the hospital on May 21, 2020 when he noticed he was struggling to walk to the toilet. 

His parents and six-year-old sister, Sofia, (pictured right) were each DNA tested for the typically hereditary disease - but none of them had the gene

'William was going around like normal but suddenly his leg would give way and he'd fall over,' Mr Howard said. 

'He'd laugh it off, go around, and it'd happen again. We thought he was joking about it but then it became more constant. 

'So we drove him to hospital, where he was told initially he might have broken his coccyx.

'They recommended we transfer him [to a specialist hospital] for further tests, so we drove him.'  

At first, doctors feared it may potentially be down to Covid — due to it being the beginning of the pandemic and doctors didn't want to rule anything out. 

But after a test came back negative, medics told the couple it may actually be down to stress.

'William was watching silly things about Minecraft on YouTube,' Mr Howard said. 

'He was getting worked up. So we thought this must be the reason.'

'He literally had his game thrown in the bin while he was with the doctor, but then the weakness began to affect his upper body.'

William was sent for further tests, but he had a full-body tonic-clonic seizure which causes uncontrollable stiffening and twitching of the muscles.

He was then put into an induced coma to protect his brain from damage while doctors did more tests. 

Doctors eventually diagnosed him with mitochondrial disease, an umbrella term that covers several syndromes caused by defects with the mitochondria — powerhouses of cells that give our body energy to function.

Around one in 5,000 people have a mitochondrial disease, according to estimates.  

But William is said to have a particular type, relating to a faulty protein called DNML-1.

Only nine others in the world are thought to have the same type, his family say.

There is no cure, with treatments merely being supportive to relieve seizures and other hallmark symptoms like muscle weakness and visual problems. 

Some patients suffer from dystonia, which a movement disorder that can cause uncontrolled muscle cramps and spasms. It can also include parts of the body twisting into unusual positions.

William wasn't given an official prognosis but doctors warn every seizure may be his last, his parents say.

'I needed a lot of time to cry and calm down,' Mrs Howard said. 

'I needed to be by myself. I couldn't believe it.'

William spent two months in a coma and woke up in July 2020. 

The couple say they were 'grateful' to have been able to make memories with William over the Christmas period - despite making do with no tree, decorations or Christmas dinner

He's since lost the ability to eat and drink and doctors say, according to the family, that the disease is slowly shutting down each of his vital organs.

After suffering another massive seizure which lasted 56 minutes, he went into his second induced coma on December 7, 2023. 

Mr Howard said: 'He got told by the doctor that this might be it, but he was only in it for a week.'

'We prepared for the worst, the day of his big seizure, he also had 13 other seizures,' Mrs Howard added. 

'The doctor was really shocked he came around after only a week - and William was even able to make it out by Christmas,' she said.