THE best friend of a family whose daughter has been diagnosed with a terminal illness is fundraising to help throw a big birthday celebration.

Claire Pugh, from Billingham, will take on a triathlon challenge to help friends Teissy Easton, Adam Williams, their five-year-old son, Kingston, and daughter, three-year-old Khiannah.

In February of this year, Khiannah was diagnosed with Leigh Syndrome, a rare but severe neurological disorder, after she suffered problems since birth.

The condition, which causes progressive loss of mental and movement abilities, usually becomes apparent in a child's first years and can cause difficulty eating, sleeping and can sometimes result in respiratory failure.

Khiannah will turn four on October 4, and her family want to mark the occasion by throwing a memorable birthday celebration.

To help raise funds for the party and to support the family in future, on Khiannah's birthday Miss Pugh will complete a 4000m ski, 400 calorie bike ride and 4k on the treadmill at Absolute Fitness in Hartlepool, with a goal of raising £400.

Miss Pugh said: "I wanted to follow the theme of four as its Khiannah's fourth birthday on the fourth.

"It’s been a fighting battle for the four of them. Because it’s such a rare disease there’s not a case study or example they can follow, and every time Khiannah's medication needs to change she has to stay in hospital for about two weeks and their lives just stop.

"But Teissy and Adam have both just taken everything in their stride. Khiannah has got a brilliant family to support her and the four of them together are just amazing.

"Despite what she suffers daily Khiannah is got so much character and she’s so full of life. She just lights up around people.

"She will tease her dad or her brother and just laugh her head off because she thinks she's so funny. For what her little body won’t allow her to do her personality more than makes up for it.

"I wanted to do this challenge to help create some amazing memories for her and her family."

Miss Pugh has set up a fundraising page on GoFundMe where any donations will be used towards organising the celebration, with the remainder to be used to support Khiannah and her family in future.