The parents of a little boy who has never said a word are speaking up on his behalf.

No one knows why four-year-old Grayson Spencer cannot talk or walk, which deprives him of the support and equipment he needs.

Now his mother Kara and father Ashley are on a crusade to raise money to buy the specially-modified gear themselves and raise awareness of the struggles families like theirs face.

The couple - who live in Nackington Lane, Canterbury, with Grayson, daughter Addison, two, and their two-month-old son Deacon - are holding a second fundraiser today.

Kara, 32, who works part-time as an accounts manager and blogs about parenting and special needs, said: "There is no other child like Grayson in the country. We were told if doctors couldn't find what's wrong with him by the age of four, we'll probably never know."

HGV driver Ashley, 36, said: "When his problems first came to light, we used to look to the future. Now, we take it day by day. We did go through a grieving process for the child we thought we would have."

A charity fun day was held in Grayson's honour last August, which raised enough money to buy him a specially-adapted trike.

The family said the effect of that single piece of equipment has been astonishing.

Ashley said: "It's had such an enormous impact. He never learned to crawl, so his hips didn't develop properly. The trike has helped him learn how to stand.

"A year ago, he was like a baby. He could just sit and shuffle around. Now, he can pull himself up on his feet, which we never thought he would do.

"He's also learned to push the pedals by himself."

For this year's event, the aim is to raise enough money to buy a walker to strengthen Grayson's legs further.

It is also to help him get around. The fundraising drive is in the absence of any support from the NHS, social services or charities, which will not provide equipment to a child with an undiagnosed condition.

The couple find themselves in a daily battle to obtain support, and spend a lot of time launching appeals against the rejections they receive.

Kara said: "The biggest problem is getting help. Children with no diagnosis don’t get the same support as those with recognised conditions.

"They are ignored by the NHS and charities, except for organisations like Syndromes Without A Name (SWAN UK).

"We've applied for things like housing, home respite and modified equipment for Grayson, but we've been turned down because they don’t know how to relate to his condition.

"They can't categorise it on paper. If he had cerebral palsy, we would get it all tomorrow. It's incredibly frustrating."

"The biggest problem is getting help. Children with no diagnosis don't get the same support as those with recognised conditions..." - mother Kara Spencer

Grayson continues to baffle doctors, who are unable to pinpoint the reasons for his development problems, despite countless tests, genetic studies, operations and hospital trips.

All they know is he has brain damage, and lumps on his brain called calcifications.

While Grayson might look like an average four-year-old boy with a mischievous smile, he has the mental capacity of a nine-month-old baby.

He communicates only by making noises and darting his eyes at objects and is not expected to ever be able to walk.

His family hope the fun day will not only raise money for equipment, SWAN UK and the Multiple Sclerosis Society, but also awareness that children like Grayson exist.

The free event will be held at Conrad Hall in Bishopsbourne from 11am to 4pm, and will feature face-painting, stalls, games, a tombola and raffle with prizes donated by Kent firms, and even a man auction.

More than 100 people attended last year's fun day, which raised £3,500 for the trike and SWAN UK.

For more information about this year's event or to donate money or prizes, visit graysonsgfd.blogspot.co.uk.