A MOTHER has told of her petrifying wait for a heart donor to save her a 20-week-old daughter's life.

Marnie Brace was born on May 10 with a rare and severe heart condition and has needed emergency medical support since to keep her alive.

She was diagnosed with Noonan's Syndrome and hypertrophic cardiomyopathy which means the walls of her heart thicken so it has to work extra hard to do even the simplest things.

She has to be fed through a tube and is struggling to gain weight in what is believed to be a genetic condition.

Her only hope for survival is a heart transplant.

Her mother Amy, 30, of Eastbourne, said: "She's a little angel. We are just enjoying every precious moment we have with her. She lights up when you come into the room, it is lovely - she is just like any child of four or five months but she needs extra help to do simple things.

"At the moment we just hope that everything stays the same but she has struggled a little bit in the last few weeks and she is so vulnerable that she catches everything going.

"Sometimes she will go a grey-blue colour when she struggles to catch her breath and that scares her quite a lot. That is really hard to watch.

"When you're pregnant you dream of what life is going to be like but you never think of this. We really wanted to have our children close together so they don't have time apart. We just want a normal life with her."

Mrs Brace fears time could run out before a heart from a baby of a similar weight to Marnie can be found. But she is not giving up hope.

She said: "We have been told the wait could be 12 months and that only one or two babies have this procedure a year. They have been successful but it means statistically we have limited a chance.

"She may not be able to hold on long enough but I just cannot think about that happening. I have to talk about it like a robot so I don't let myself think about that.

"In order for her to survive, another family will be in the position we are trying to avoid. It's not like a liver or a kidney where someone can still live. When the call comes I think I will have a panic attack. I feel petrified. I am desperate, I think about it all of the time."

Mrs Brace and her husband Nick, 42, take it in turns to sit at Marnie's bedside at the Evelina Children's Hospital in London and look after their 20-month-old son Jonah. They are staying at Ronald McDonald charity house nearby.

She hopes talking about her situation will encourage parents to think about putting their babies on the organ donor register.

Visit justgiving.com/crowdfunding/babymarniesnewheart and organdonation.nhs.uk.