Little Billy Manley, seven, was born with a one-in-a-million heart condition while his twin Tommy is perfectly healthy

A twin boy waiting for a heart transplant is being looked after and protected by his “guardian angel” brother.

Seven-year-old Billy Manley was born with a one-in-a-million heart condition while his twin Tommy is perfectly healthy.

Their mum spotted Billy was always “a bit out of breath” when playing outside with his soccer-loving sibling Tommy.

He was then diagnosed with the rare condition which causes his heart to become enlarged and press against his lungs.

Twin brother Tommy is now like a “guardian angel” looking after his sibling while he waits for a new heart.

Mum Rebecca, 44, said: “He’s like a protector. When he came to Great Ormond Street Hospital for the first time he sat with his arm on his brother’s chair and said: ‘I’ll look after him’.

“He wants to protect him. When he got back from visits he hugged him and he always wants to Facetime him when he’s away.

“They aren’t identical twins but they are close, although they argue like any siblings.”

Billy’s condition first came to light after he suffered a string of chest infections that doctors believed was due to asthma.

But the family was then dealt the devastating blow that he needed a heart transplant for the rare restrictive cardiomyopathy.

The condition makes the bottom of Billy’s heart muscle stiff so the blood goes to the top and enlarges his heart.

Tommy was sent for tests after his brother’s diagnosis but was given the all clear.

Rebecca, of Cardiff, said: “It was a big shock. I have always known something was wrong with Billy.

“There was a big difference between the two boys growing up. Tommy is very active and Billy is more quiet.

“When I walked with them Billy was always a bit out of breath.”

Rebecca had taken Billy on repeated trips to the doctors before he finally underwent tests at the University Hospital Wales in Cardiff.

She said: “I have got mum guilt for always saying to him ‘come on, you can do it’ when he was ill. He gets cold and has no energy and eats hardly anything. It’s heartbreaking.

“I think I am still in shock from the diagnosis. Billy has been taking it all in his stride and has been amazing and thankfully we are aware of it now.”

Mum-of-two Rebecca and dad Gavin have also had genetic tests but nothing was found.

Billy is now under the care of Great Ormond Street Hospital in London and is on the urgent heart transplant register.

He is also on a long course of antibiotics to clear up any chest crackles to make sure his lungs are clear and ready for the transplant.

Rebecca, who is studying for a degree in Quantity Surveying and Commercial Management, said it has been a “whirlwind” six months.

She added: “I think coping and keeping going is all I can do.

“In the daytime I am strong bit in the evenings going to bed and thinking about it I am heart broken.”

Rebecca is also fundraising to help Billy with his treatment and raising awareness for organ donation.