The genetic disorder means her body does not produce an enzyme needed to break down certain sugar molecules, which can then build up in the body, causing problems in bone development, growth and mobility.
She was diagnosed at age 2 after a Plunket nurse noticed her back was more curved than usual. At 5 she had her first operation at Starship, to stabilise the connection of her head and spine. Surgery for wobbly knees followed at 8 and at 12 she had metal rods placed in her back to help correct the curvature of her spine.
Sarah progressively lost the ability to walk from 8.
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But things have been looking up for Sarah since she was accepted in 2012 for a drug trial run by a United States company.
The drug, Vimizin, is a replacement for the enzyme, and she receives it as a weekly infusion into a vein. She lived in California with her father for 18 months for the trial, then in April returned home and now receives the infusions at Wanganui Hospital.
In February, Vimizin became the first US Government-approved treatment for Morquio type A, Sarah's version of the condition.
The company, BioMarin Pharmaceutical, has agreed to supply it to Sarah at no charge, for life.
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"It's been amazing," she says. "I've got less joint pain and more energy. I can do more during the day.
"It has been one of the best things we have ever done. It has been difficult at times because Mum would stay back and work and send money over to Dad and me."
Sarah, who likes to swim, is uncertain about the long-term effect of the drug.
"My swimming coach notices I'm kicking a lot stronger. Whether or not I will be able to start walking I'm not sure; I'm hopeful."
"To give Starship the best equipment is a priority because it helps so many children," she said.
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