A ‘happy’ young boy with a genetic mutation never seen before in the world probably had an undiagnosed heart condition which caused him to die suddenly.

Eleven-year-old Tyler Ryan died unexpectedly on February 12, 2021, after his mother, Donna, found him unresponsive in his bedroom at their home in Tow Law, County Durham.

After an agonising wait of nearly three years for answers - including a pathologist initially wrongly saying he’d died of an allergic reaction - the family finally got an explanation about his death yesterday (Tuesday, October 17).

Read more: Clinician treating man who took own life didn't know of 37 calls to crisis team

Mum Donna yesterday paid tribute to her “happy, loving” son and “mummy’s boy”, who loved gaming, football and playing with his siblings.

Tyler is likely to have had an undiagnosed heart condition called CPVT (Catecholaminergic polymorphic ventricular tachycardia) – an inherited condition that causes disturbances in the heart’s rhythm in otherwise healthy children, an inquest into his death heard ysterday. The abnormal rhythms often occur at times of high adrenaline levels, such as during exercise or strong emotion.

A post-mortem examination by paediatric pathologist Dr Annavarapu initially suggested Tyler’s medical cause of death was anaphylactic shock, a severe allergic reaction.

But there was nothing found in his room that could have caused the reaction and Donna fought for a second opinion knowing her son had no history of allergies.

The Northern Echo: Tyler Ryan from Tow Law.Tyler Ryan from Tow Law. (Image: FAMILY)

Tyler had previously collapsed on several occasions, but he had never received a diagnosis. It is now thought this was a sign of his CPVT.

The exact genetic mutation which caused the condition has never been seen in any other human in history, consultant in clinical genetics Dr Paul Brennan told Newcastle Coroners Court.

He added the heart condition was “extremely rare” and that he wouldn’t expect a GP to have heard of it when asked if it could have been picked up.

“In your opinion it is highly likely that he had CPTV and his death was most likely caused by a fatal heart rhythm disturbance,” assistant coroner Carly Henley summarised.

The inquest on Tuesday heard Tyler’s father, Gareth, had checked on him in bed at about 10.40pm the previous night.

His parents believed they had heard him awake the next morning, and computer activity logs show he used the internet at 9.58am.

The Northern Echo: Tyler with mum Donna.Tyler with mum Donna. (Image: FAMILY)

But when mum Donna, who was on maternity leave at the time, went to see if her son wanted breakfast at 11.02am she found him slumped in his gaming chair in his bedroom and called 999.

Police, air, and ground ambulance teams rushed to his aid. Air ambulance crew member Dr Johanna Paterson recalled how it was a snowy morning with conditions meaning he had to be airlifted to the RVI in Newcastle.

She said he “looked dead” when they arrived and medical professionals were unable to find any shockable rhythm from his heart, meaning they could not defibrillate.

A short time after his arrival at the RVI, at 12.30pm, Tyler was pronounced dead.

His parents and siblings will now be tested to hopefully save any of them with the same genetic mutation from risk.

Speaking after the inquest Donna, a care worker, said: “He loved gaming, football – he was a really healthy lad and a bit of a mummy’s boy.

“He was a massively happy lad and he’s a massive miss in the family.

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“When we had his baby sister, she was nearly four months old when he died, he loved her. We bring her up to go to the cemetery and know that’s her big brother. He’ll definitely be watching down on her.

“I knew it wasn’t anaphylactic shock, I could have shrugged my shoulders, but I stood up for that and today feels like a bit of a victory.”

Assistant Coroner Carly Henley for Newcastle and North Tyneside praised Donna for her determination in finding out what happened to her son.

Miss Henley said: “I am grateful to you for pursing this”.

She concluded Tyler had died of natural causes and listed his medical cause of death as sudden death in childhood associated with the gene mutation.