Rare disease means protein becomes acid which burns Christchurch girl Keira Hubball

Vickie Hamilton with 6-year-old daughter Keira Hubball who has a rare disorder which turns protein into acid which burns her organs. Photo/Martin Hunter

Keira Hubball's life depends on a carefully planned diet.

Unlike other 6-year-olds she can't pick and choose what she eats. In fact, she's only ever nibbled on food here and there; she is tube-fed every three or four hours.

The bubbly Christchurch girl was born with a rare condition called methylmalonic acidemia.

It means her liver can't metabolise and break down proteins like normal. If there is too much protein in her body she ends up with a toxic level of methylmalonic acid in her bloodstream.

It burns her from the inside causing serious damage to her vital organs.

Keira is one of three people in New Zealand with the disease which about one in 48,000 children are born with.

She's been poked and prodded by doctors more than most of us will be in our entire lives. She's already had a number of blood transfusions and is facing the prospect of kidney and liver transplants.

Her growth and development have also been delayed, she is about the size of a 4-year-old and struggles to string a sentence together.

Despite all that, she is a happy child who "melts people's hearts".

"She has this way about her where she really seems to bond with everybody and anybody. Even when she's not feeling her best she's happy and full of life. She's incredible. I can't imagine what she's going through," mother Vickie Hamilton said.

"It's her life. She doesn't know any better."

Hamilton said it was clear all was not well when her daughter started struggling to feed and breathe soon after she was born. Her condition was picked up as part of the newborn screenings.

Keira Hubball, 6, and mum Vickie Hamilton. Keira has the rare disorder methylmalonic academia. Photo/Martin Hunter

It's a genetic disease and requires both parents to be carriers for a child to be affected.

Ever since then it's been a constant case of tweaking her diet and medication to help her lead as much of a normal life as possible.

She gets sick often and it comes on quickly. When she is really sick she vomits blood which burns her chin.

"It can be quite a shock. The last time that happened she was also bleeding on the inside of her cheeks.

"It's scary. It's about getting her to hospital as fast as we can and making sure they are ready for her."

The acid has already done so much damage to her kidney, doctors are staring to talk about a transplant.

At her last test six months ago, Keira's kidney was only functioning at 33 per cent.

"We were all in shock. We knew it was going down but we didn't think it would be that low," Hamilton said.

She expected a test next month to show further deterioration. Most people started dialysis when their function dropped to 15 per cent.

A liver transplant had been discussed in the past but decided against because, although it would improve Keira's quality of life and bring the acid levels down, it was not a cure.

Now, with a kidney transplant on the cards, the possibility of a new liver is a discussion the family will face again.

For Hamilton and husband, James Hubball, it is often a difficult and lonely journey.

"Even to this day it's a world of unknowns," Hamilton said.

"Keira doesn't have the sentences to explain how things are going and what she's feeling which can make it tough as well because we don't know if she's feeling sick."

The family kept tabs on other children around the world with the same condition; some lost their battle while others kept soldiering on.

"Even though you get the sad stories, you get the hope as well. You always look at hope."

The family hope Keira will be able to live a happy life and aim to make it as normal as possible for her. She does half days at school to help give her some normality.

"She is incredibly strong. You look at her and you wouldn't even know," Hamilton said. "She's a trouper."

• A Givealittle page has been set up to help take financial pressure off the family and allow them to spend more time together and be by Keira's side when she is unwell.