A mum who watched helplessly as her baby suddenly lost his mobility says NHS policy not to screen for his condition at birth put his life at risk.

Amy Aldridge, from Whitstable, noticed her son Harry's breathing was erratic when he was born, but was told by medics it was normal.

Eight weeks later, it was confirmed he had spinal muscular atrophy (SMA) type one - the most severe type - but the diagnosis came too late to prevent long-term disability.

The genetic disease weakens Harry's muscles and affects his mobility, breathing and ability to swallow. There is no cure, but therapy can help manage the condition.

Although the tot displayed symptoms within hours of his birth, it took two months for a doctor to listen to his mum's concerns and send a sample away for testing.

Harry’s family believe this delay, which meant he had no treatment for the condition in the first months of his life, will have long-term effects as the muscle that Harry developed before he was born wasted away and will never fully return.

The NHS says in the past babies with type 1 SMA rarely survived beyond the first few years of life, but in recent years, outcomes have improved with early diagnosis and treatment.

Amy, 34, believes that without her insisting Harry was examined, he might not have survived.

She said: “If we hadn’t found out about Harry when we did, or we hadn’t pushed to try and find out what Harry had, he may not be here now. Because without treatment, a lot of babies don’t survive past a year.”

Now, Amy and her husband Nick, 35, are supporting SMA UK’s campaign to introduce newborn screening for the condition.

Harry was born at the William Harvey Hospital in Ashford, and while his mum suspected something was wrong, she felt she had to trust the medical professionals who told her not to worry.

Amy said: “I questioned it with the midwives and they took him away and checked him over. They said, ‘there’s nothing to worry about’.

“But it didn’t sit well with me because it didn’t look normal to me but I’m a first-time mum surrounded by midwives and so I followed what they said.”

Amy says it is painful for her to think about the progress Harry would have made by now if his condition had been picked up sooner.

"Babies born with SMA generally start losing any muscle tone they initially had when they were born from about 6-8 weeks," she said.

"So he was able to move his arms and things up until about six or seven weeks old and then he just didn’t move at all.

“If he had been screened at birth he probably wouldn’t have to be on a ventilator. If he had had treatment at birth he wouldn’t have lost that initial movement that he had.

“If he had been screened at birth and then treated within the first two weeks, things would be a lot different for Harry - a hell of a lot different.”

The SMA UK campaign is calling for the NHS to add the disease to the list of conditions it tests for in the heel prick test all newborns have at about a week old.

Campaigners say this would not only improve outcomes for babies like Harry, but would also potentially save the NHS money from a reduction in expensive treatments.

Harry is currently being considered for a round of gene therapy, which would cost £1.7 million.

His parents say that even though it is too late to make a difference for Harry, they are fighting to introduce newborn screening for other families.

“It could change things for a lot of people," Amy said.

"They wouldn’t have the heartache and the stress that we went through. Most American states screen at birth now, but over here they don’t.

“The Department for Health and Social Care say they don’t see a need for it, but there is a need because it’s a horrible thing to go through and it’s not nice for a baby not to be able to move and to have all these medical procedures.”

Despite his challenging first few months, Harry is now making progress thanks to regular Spinraza injections into his spine and weekly physiotherapy sessions.

Now 15 months old, he recently sat unaided for the first time.

There have also been developments in medical research, and new treatments are making their way through testing, giving the family hope.

But Amy said: “There’s lots of positives at the moment but we do get our days where we wonder if he’ll ever make it to those milestones.

"He’ll be taking longer than expected and we’ll wonder, but then he’ll do something else and we’ll realise we’re going in the right direction.”

The family has set up a GoFundMe as Harry’s ill health has put a strain on their finances due to Amy being forced to quit her job supporting disabled children to be a stay-at-home mum.

The couple say their main goal is simply to raise awareness of the condition, to try and prevent the “stress and heartache” their family went through.

Amy added: “Even going into the local hospitals, when I say he has SMA, they say ‘what’s that?’

"It’s one of the top killers for a baby in the first year. There is not enough awareness."

The government's UK National Screening Council says screening is not currently recommended for this condition because there is not enough evidence to show how effective it would be.

The council also says the best way to support people with positive results is not known, and there is no evidence for effective treatments for people who do not show symptoms.

A Department of Health and Social Care spokesperson said: “The UK National Screening Committee continues to monitor of developments in Spinal Muscular and welcomes published data around the use of new drugs.

“The Committee is in the process of reviewing evidence for Atrophy as a population screening programme, and is engaging with a variety of stakeholders.”

It was announced on Friday that a review of this recommendation is currently underway.