Many people will tell you their grandchild is one in a million, but in the case of little Zach Armstrong, the statistic is sadly only too true.

The grandson of Tura Beach residents Tim and Mary Eastman has a condition so rare, he is one of only five sufferers in Australia.

Zach suffers from Fibrodysplasia Ossificans Progressiva (FOP) FOP - a genetic condition that gradually restricts all movements due to progressive abnormal bone formation in soft tissue such as muscles and connective tissue around the joints.

“Tissue such as muscles and tendons basically turn to bone and create a second skeleton. It is very painful and there is no cure,” Mr Eastman said.

Zach, one of only 600 sufferers worldwide, was born on Australia Day 2006, and although seemingly in good health, his toes were deformed, which is a clear indication FOP maybe present in his body.

Because of the disease’s rarity, doctors struggled to find the cause of his deformed big toes and a spate of seizures at around nine-months-old.

When Zach was 22-months-old he became suddenly unwell with swelling around his left eye.

He was admitted to hospital and the swelling spread to other areas of his body including his neck, back, trunk and arms.

As a result, Zach has been left with stiffness of his upper body including his neck, jaw, shoulders, elbows and hands.

He is unable to move his shoulders, his elbows are permanently flexed and he has limited movement of his hands.

“The doctors couldn’t work out what was going on,” Mr Eastman said.

“In fact it was a family friend who researched Zach’s symptoms over the internet and they came up with FOP.”

FOP was discovered by University of Pennsylvania doctor Fred Kaplan, who has since devoted his life to treating FOP sufferers and finding a cure.

“The biggest problem facing Dr Kaplan is the lack of funding. He doesn’t charge any of his patients and receives only 25 per cent of his budget through grants,” Mr Eastman said.

“The other 75 per cent of his funding comes entirely from the families of the people affected.”