Two-year-old Bryson's legs could dislocate at any moment, he is deaf, will never talk and may never be able to crawl, walk or feed himself unless he gains more strength in his muscles.
The toddler has Alpha-Thalassemia Mental Retardation Syndrome or ATR-X syndrome - a newly discovered disorder that causes learning difficulties, skeletal and muscular difficulties and sometimes seizures.
As far as his parents know, he is the only child in New Zealand with the illness.
Stacey Blunsdon said she and her partner Tayler Howard were "completely and utterly heartbroken" when they heard the news.
"It's genetic and it has just been confirmed that I'm a carrier of the ATR-X gene," she said.
"We have needed a lot of support to get our heads around the seriousness and how much Bryson will depend on us for the rest of his life."
Females can be carriers of the syndrome with no obvious signs and the symptoms only become evident in males.
Bryson was diagnosed with the condition late last year and since then the Napier family has been working hard with physiotherapists and doctors to manage his condition.
Blunsdon said there was a 50 per cent chance that her son would learn to walk, but it depended on his muscle development. The family hope to raise enough money to fund special suits for Bryson.
The Dynamic Movement Orthosis (DMO) suits can be specifically designed to help the wearer function normally. The suit can re-align the body, improve posture and help with pain relief.
DMO suits cost thousands of dollars each and Bryson's family order them in from Britain.
Blunsdon said the suits needed to be constantly updated as her son grew.
The family has set up a fundraiser for the ongoing costs of Bryson's care at givealittle.co.nz/cause/brysonsjourney.
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