A COURAGEOUS six-year-old has been diagnosed with a rare genetic disorder that could put him in a coma at any moment.

Kayden Hurrell suffers from ornithine transcarbamylase deficiency (OTCD) - a condition that causes dangerous levels of ammonia to build up in the bloodstream and could be deadly if left untreated.

The toxic compound is a waste product which forms when the body breaks down protein but a lack of OTC enzyme needed to flush it out creates an accumulation and can lead to severe headaches, sickness, lack of appetite, tiredness and confusion.

In extreme cases, the hereditary condition can cause coma, brain damage and even death.

Greenock schoolboy Kayden was diagnosed a year ago and has to take special medication and watch what he eats to keep his symptoms at bay.

Along with aunt Tina Stanton-Hurrell and grandmother Christina Hurrell, he is preparing for a 3.5-mile walk to raise awareness of the condition and help others affected by it.

Nana Christina, 51, from Port Glasgow, said: "His body doesn't break down protein.

"The side effects are a sore head, hallucination, sickness and if it's really bad he can go into a coma.

"I think what he's doing is brilliant."

The walk, from Christina's house in Castlehill Avenue to Kilmacolm, will also be in memory of her late partner and Kayden's grandfather Harry Stanton, who died in 2011 aged 47.

Like many of the family, he was a carrier of the OTCD gene and suffered from multiple sclerosis (MS) and latterly contracted tuberculosis.

Some of the proceeds from the walk will go to the MS Society in his name.

Christina said: "Kayden was only 10 days old when Harry passed away, he only held him once.

"Nobody has heard of OTCD, even the doctor hadn't heard of it.

"It turns out it runs in the family."

Kayden's condition means that even a bump to the head could be dangerous, but the St Patrick's Primary pupil does not let it hold him back and he says he cannot wait for the sponsored walk on July 28.

He said: "I love walking and running.

"I'm fastest in the whole class."

His aunt Tina, 19, is organising the charity walk.

She said: "I'm also an OTCD carrier and Kayden's wee brother has it as well.

"He has special medication because if he gets a sore head he can go into a coma.

"He's mostly gets sore heads and needs his special medicine as soon as he's not well as it can effect the OTCD and he needs to watch what he eats or that can have an impact too.

"The walk is also in memory of his granda, my dad.

"All the money we raise will be halved between MS Society and the OTC department at the Royal Hospital for Children."

The family are also organising a charity night in The Comet Bar on November 2 to mark the seventh anniversary of Harry's death.

The Port town centre pub was his local and he used to sing there.

Everyone is welcome to the fundraiser and there will be a collection on the night.

To donate, visit www.justgiving.com/fundraising/tina-stanton.