Ryan was also born with a heart murmur and suffered from epilepsy. He overcame many hurdles, surviving major heart and hip surgery as well as countless chest infections.
"He had his first epileptic fit at eight months, then more things started to happen like chest infections and bronchial pneumonia," said Michael.
"His longest time in Starship was 35 days - that was hard. He was having trouble swallowing and had to be fed through a tube. He was 15 months when we were told he had to have heart surgery."
The major surgery to repair holes in his heart was a success.
"That changed him; he started to grow and develop in his own way. The first time we heard him laugh was when we were looking at some American show with canned laughter and we were laughing, next thing we heard Ryan giggling away."
The couple had to fight for two years to gain funding for alterations to their home for Ryan's wheelchair.
"We went through a lot," Michael said. "It was only when we went to our MP Jonathan Coleman that the ball started rolling and we got approved for $50,000 worth of alterations like the ramp and hoist for Ryan.
"Our lives have been on hold. Everything we did we did for Ryan. I got made redundant and am still looking for work. Michelle had to go part time to look after Ryan. It's been hard but he was a joy. We are proud to be his parents."
He couldn't walk or talk but, from the age of 5, he could ride horses with North Shore Riding for the Disabled.
The group is aimed at encouraging confidence, independence and wellbeing for people with disabilities, through therapeutic horse riding. Ryan loved the horses and loved riding. In lieu of flowers, his parents are asking for donations for the group.
Michael said the couple tried to give their son a life that was as normal as possible. He attended Wairau Valley Special School and spent a lot of time at the Wilson Home Centre.
"He had so many friends. He loved school and he loved his teacher Pen Adams. He starred in the school production of Alleycats. He loved music," Michael said.
But his health deteriorated after a lung infection this winter.
"Winter was his worst time of year. He suffered from colds and flus and they lasted for weeks. After the lung infection he went into Wilson's for respite but developed a fever. He was okay and we got him home last Friday but he wasn't the same Ryan. He just wanted to sleep," his father said.
On Wednesday morning, his parents found he had stopped breathing.
"We called 111 and I started doing CPR," Michael said. "The ambulance turned up and four of them were working on him but he passed away."
Ryan will be farewelled at the St Leonard's Chapel at the Wilson Home Centre in Takapuna.
"We miss his smile, his big brown eyes and his beautiful dark curly hair but he is in a better place," his dad said. "He is up there running around, kicking a ball, eating lollies - things he never got to do on Earth."