EVERY parent thinks their child is one of a kind, but Ryder Whelan is more like a four in seven billion.

The two-year-old's rarity means he is missing a lot in life.

"He's got a few things happening within his tiny little body," mother Nicole Kras said.

For one, the Geelong boy was born without irises.

While most parents ooh and aah over whether their child will have blue or brown eyes, Ryder's were black.

"Because he was our first, we thought they were normal and the colour would change," Ms Kras said.

At six weeks, he was diagnosed with aniridia, a symptom of WAGR syndrome - a series of congenital developmental abnormalities.

Ryder cannot see out of his right eye and in the other his sight is pixilated.

He also has 14 gene deletions, one of only four people in the world with such a genetic make-up.

His medical conditions include glaucomas.

He has had more than 30 operations on his eyes, including attempts to stop the glaucoma strangling his optic nerve.

Doctors have tried cutting parts of the eye, carrying out laser work and inserting a plate with donor tissue.

But the toddler can still see out of his left eye.

"They liken it to a computer screen where you have megapixels," Ms Kras said.

Another complication is his body's inability to control its growth.

He is prone to put on weight, despite a healthy diet.

"One of the genes regulates body mass, so he is already the size of a three or four-year-old," Ms Kras said.

His parents say they never know what he is missing until another health issue emerges.

"His genetic build is so rare there are only one of four people in the world with it," Ms Kras said.

Yet Ryder is a bright boy who loves the sound of his dad's Harley and being pushed on swings.

"We've had everything thrown at us, but he's been a good kid through it all," she said.

© Herald and Weekly Times.