A St Albans toddler who nearly died when doctors failed to diagnose a rare heart defect celebrated his first birthday yesterday - a date nobody thought he would see.

Dominic Potter, of Ramsbury Road, spent the first months of his life in and out of hospital suffering from transposition of the great arteries, which doctors failed to diagnose until he was five weeks old.

The little lad was rushed to Watford General Hospital, but the severity of his illness forced a transfer to a specialist heart unit at London's Royal Brompton Hospital where he spent five weeks in intensive care undergoing major surgery to correct the potentially fatal problem.

His mother, Karen, recalled: "No oxygen was getting into his system. He wasn't putting on weight and he had gone a purpley blue colour, not all the time, mainly when he was laying down. For the first weeks of his life I was always holding him up. He had bad nappy rash, thrush in his mouth and an infected belly button. He had been getting weaker over five weeks and it was becoming apparent that something was wrong.

"When he was in intensive care it was two steps forward, two steps back. I never thought more than one day ahead."

But the operation was a success and little Dominic did make a full recovery. He is now back at home with his mum Karen, dad Tim, and two-year-old sister Kate, and celebrated his first birthday yesterday. On Saturday friends and family will gather at a children's play centre in Radlett for Dominic's a big party.

Karen said: "He's such a happy, smiley little boy. He's started to walk about. He's really interested in playing with light switches, plugs and climbing the stairs.

"He's like any other one-year-old. He's caught up on his weight and he's a joy."

Dominic's family are holding a black tie charity ball in St Albans next month to raise money for life saving equipment at the Royal Brompton Hospital.

Karen said: "The last year has been stressful and worrying, but the moment Dominic was taken under the care of the Royal Brompton I felt happy that the right people were caring for him. Since then he's gone from strength to strength. We're really pleased with the way he is today - a happy one-year-old. I couldn't imagine it any other way.

"I'm so happy Dominic is still here and our family is complete. We can now help other families achieve that aswell."

Tickets for the event cost £35 and include a champagne reception, hot dinner buffet and live band. To find out more about the event or buy tickets visit www.justgiving.com/dominic-potter or email Karen Potter on babyheartball@hotmail.co.uk