Brave twins take their first steps aged 28

James and Neil Weir, who had been confined to wheelchairs all their life, were not expected to live past their teens, so severe is their illness. However, they have repeatedly proven doctors wrong, battling through hours of physiotherapy to strengthen their frail legs.

Their hard work finally paid off when, within days of each other, they walked a few steps without help. Their mother said: "Every parent looks forward to the milestones, like the first words and the first steps. Those first steps may have come 25 years late, but I'm just as proud. It's a wonderful moment."

Isobel and John Weir, from Lhanbryde, Moray, knew there was a problem when they were born. They were in hospital for the first two months of their lives. They didn't seem able to hold their heads, arms or legs up by themselves.

A specialist at the now closed Woodlands Hospital in Aberdeen told the parents their sons had cerebral palsy. They were, he said, doomed to an early death.

They boys stunned everyone when they reached 19. Then, a medical expert realised there had been a mistake.

The twins did not suffer from cerebral palsy after all but Cornelia De Lange syndrome, a rare genetic illness that affects one in 10,000 people.

It stunted the boys' growth – they are 5ft tall – caused some brain damage and weakened their limbs and hearts. Mrs Weir, 62, a retired nurse, said: "It suddenly made sense why they would never been able to walk.

"When they were three, they tried to stand and toddle but kept falling over. When they were diagnosed, I knew it was because their legs couldn't support them."

Mr and Mrs Weir, who also have two daughters, Moira, 37, and Alison, 35, looked after the twins at home until they were 25. They now live with two disabled friends and two 24-hour carers in their own home.

The pair have confounded doctors simply by staying alive. Six years ago, both twins managed to escape their wheelchairs for the first time and took a few steps pushing a walking frame.

Since then they have persevered, undergoing two hours of physio a week. But Mrs Weir thought that, ultimately, all their hard work would be in vain.

"I watched my three grandchildren all walk for the first time," she said.

"It was strange to think my grandchildren could walk before my sons. But I just assumed it would never happen for them – until James took his first steps towards me. It felt like a miracle."

James walked first, quickly followed by his brother. Doctors have now ordered custom-made, reinforced boots for the twins to make it easier for them to stride about.

"They have got to this moment with sheer hard work," Mrs Weir said. "They just wouldn't give up, ever. The whole family is immensely proud of them."