Young Arlo Woodward’s grin is so infectious that it's almost impossible not to smile back when he puts his two front teeth on display.

The cheerful 15-month-old Whakatāne boy was diagnosed this year with bilateral perisylvian polymicrogyria, a rare condition that causes the brain to have too many small folds.

For Arlo, these are located on both sides of his head, above his ears. An MRI also found that the front of his brain is smooth.

To parents Tamara Holland-Goodwin and Leon Woodward, Arlo is the most amazing child in the world.

They want the best for their baby, so they’re going out of their comfort zone to share his story and fundraise for expensive private treatment in Rotorua.

When asked to describe her son, “happy” is the first word to come to mind for Miss Holland-Goodwin.

“He's just one of a kind. He's amazing. He's literally the happiest boy you’ll ever meet. He's just happy to be alive, happy to live, he’s smiling at everything. He's got such a cute and fun personality.

“With everything we’ve been through with him, he’s never stopped smiling.”

Miss Holland-Goodwin was studying to become a personal trainer when she discovered she was pregnant with Arlo. It was a surprise, but a welcome one.

Mr Woodward said he had a weird feeling one day that his partner was pregnant and encouraged her to take a test.

“He just had this weird intuition. I took a test, and I was pregnant.”

Miss Holland-Goodwin said her pregnancy was smooth. Every scan showed that Arlo was healthy, and her birth was textbook – labour for 26 hours, active labour for eight and pushing for one, ending with the new dad catching his perfect baby boy.

Almost immediately they ran into issues with breastfeeding. Miss Holland-Goodwin’s anatomy and Arlo having a severe lip and tongue tie triggered multiple trips to the doctor when he had trouble feeding.

They transitioned to formula and that worked – until it didn’t.

“He almost went into survival mode,” she said.

“He would only eat enough to survive. We went to A and E probably three or four times.”

There they met their paediatrician, who at a follow up appointment in mid-January noted that Arlo was not meeting his milestones, and he was moving abnormally.

A couple of weeks later, Arlo became sick with an upper respiratory infection and fever, and he stopped feeding entirely.

He was admitted to hospital for a few days and fitted with a nasogastric tube, at which point he was diagnosed with an oral aversion.

It is still unknown what caused Arlo to miss his milestones. Miss Holland-Goodwin said, understandably, the focus was largely on making sure Arlo was getting sufficient nutrition.

Genetic tests analysed in New Zealand and Finland have shown nothing abnormal to indicate a cause for Arlo’s developmental delays.

At about eight months old, Arlo was put under general anaesthesia for an MRI. They got the results two days later showing the polymycrogyria and abnormal sulcation (smoothness).

Miss Holland-Goodwin said the affected parts of Arlo’s brain control sucking, swallowing and speech.

“Obviously for him, as feeding got harder and his body wasn’t developing as it should, he became averse to the boob, the bottle and feeding in general.”

Arlo is now fed through a gastrostomy tube directly into his stomach.

He also has cerebral palsy, an umbrella term that refers to a group of conditions affecting movement and posture.

There are multiple different types of cerebral palsy, and it is not yet known what Arlo has, or what caused it.

Arlo has low muscle tone in his upper limbs and high tone in his lower limbs. He has hyper reflexes in his legs but isn’t strong in his upper body, and his brain doesn’t send the right messages to control his limbs.

To stimulate that part of his brain and to work the muscles that will allow him to stand independently later, he spends an hour every morning in a standing frame. The frame is funded by Child Disability Services, as is another modified hybrid wheelchair-highchair.

As a side effect of his medical conditions, Arlo has a very active gag reflex. It is triggered by any cough or sneeze and is sensitive to anything in his mouth.

He has experienced two seizures at home and one while the family was shopping in Countdown. Seizure medication has helped.

“It never gets easier. It's scary every time,” Miss Holland-Goodwin said.

Arlo currently receives physiotherapy twice a week to stimulate the parts of his brain that aren’t being engaged because he isn’t crawling and moving the way other babies his age do. He is just starting to roll, can’t sit independently and can only bear weight on his legs for a certain amount of time.

“He's still a fair way away from being able to move the way that he wants to,” Miss Holland-Goodwin said.

The aim is to help him progress in the line of development.

Intensive therapy programmes overseas have helped drastically improve the lives of similar children, and Australian company Centre of Movement opened a permanent Rotorua clinic offering the service just a few months ago.

It's expensive, but it has offered Arlo’s parents hope for their boy. The centre told them there is a baby of a similar age who is currently thriving in the programme.

They have been quoted $10,000 for three weeks of therapy, with costs tapering down for shorter periods. It's not a one-off and Arlo would need to return for further sessions.

At 15 months old, Arlo’s progress has slowed, and his parents are keen to see momentum pick up again.

“When we heard the price, but that there was hope for improvement, we couldn’t just not try. Arlo is so happy, and he deserves to have every chance, no matter the cost and no matter where it is,” Miss Holland-Goodwin said.

“When you become a parent, you just want to do everything you can for them.

“We have no idea if this will help, but we can’t not try.”

The couple see the programme as a beginning towards Arlo reaching milestones, and it gives them hope of him having an independent future, even if the therapy is something they must continue to fund for years to come.

“I want him to come to the gym with me. I want him to thrive. Whether it looks different or not, I want him to do what any other kid can do. I don’t ever want him to look at another kid and be like ‘Mum, why can’t I do that?’” Miss Holland-Goodwin said.

“I want him to be able to do everything.”

Mr Woodward said it was tough seeing his child suffer and not be able to do the things he wanted to.

“Why is it our kid that has to suffer? He's perfect in his own way. We wouldn’t change him for the world. I wouldn’t change him for any other kid. All we want is the best for him.”

The couple set up a Givealittle fundraiser to raise the money required to get Arlo into the Centre of Movement. So far, they have raised nearly $4000 and have had a generous donation from the Dream Chaser Foundation, which was set up by a local mother who lost her son to childhood cancer.

“I wish we could message every person who has donated individually or give them a big hug,” Miss Holland-Goodwin said.

“I just want them to know that no matter how big or how small their donation was, it goes so far in our hearts, because it’s going towards the one thing that is most important to us.

“Literally, just thank you. I don’t even have the words. I’m just so grateful and I hope one day that we will be able to give back.”

Donations can be made to support Arlo through Givealittle: https://givealittle.co.nz/cause/help-arlo-access-life-changing-therapy