Medical professionals have commended singer Jesy Nelson for openly discussing her twins’ diagnosis with a rare muscular disorder, bringing much-needed attention to a devastating illness that can affect newborns from birth.

The 34-year-old former Little Mix member and her fiancé, rapper Zion Foster, welcomed their twins, Ocean Jade and Story Monroe Nelson-Foster, prematurely in May.

In a heartfelt video shared on Instagram this past Sunday, Nelson revealed that her daughters have been diagnosed with spinal muscular atrophy type 1 (SMA-1), a severe condition impacting around 70 infants annually in the UK.

Fighting back tears, she stated, “We were told they might never walk, and the best course of action is to get them treatment and hold on to hope.”

Nelson explained that the diagnosis came after enduring four challenging months of hospital visits, and she emphasized her desire to alert other parents to the symptoms since “time is crucial” when dealing with the disease.

“I believe that if I can spread as much awareness as possible about this condition and its signs, then something positive can emerge from this situation,” Nelson expressed.

So just what is SMA-1, what are the warning signs – and what is the outlook for babies diagnosed with the condition?

The Daily Mail spoke to world-leading experts to reveal exactly what parents need to know. 

Doctors have praised Jesy Nelson for speaking out about her twins’ diagnosis – shining a light on the brutal reality of a devastating muscle disease

What is spinal muscular atrophy?

Spinal muscular atrophy (SMA) is a rare inherited neuromuscular condition that affects the motor neurons – the nerve cells in the spinal cord responsible for controlling muscle movement.

It is caused by a fault in the SMN1 gene, which normally produces a protein essential for keeping these motor neurons alive. 

Without enough of this protein, the neurons gradually die, meaning messages from the brain can no longer reach the muscles and the muscles slowly weaken and waste away.

The condition is inherited in an autosomal recessive pattern, meaning a child must inherit a faulty copy of the gene from both parents. 

Around one in 40 people carries the altered gene, often without knowing it. 

According to the NHS, about 70 children are born with SMA each year in the UK, and without treatment fewer than one in 10 (8 per cent) will survive to the age of two.

The website of the charity SMA UK says that ‘early detection of the condition is critical’ for better outcomes for babies, adding that the UK is ‘shockingly far behind’ in not including SMA in the NHS newborn blood-spot screening test, which is offered when a baby is five days old and currently looks for nine rare but serious conditions.

Nelson said she decided to speak publicly in the hope of helping other families spot the warning signs sooner

The different types of SMA

Doctors classify SMA into several types depending on how early symptoms appear and how severe the disease becomes. Type 1, known as SMA-1, is the most common and most severe form, with symptoms usually emerging within the first six months of life. Type 2 typically develops between six and 18 months, with children often able to sit but not walk.

Type 3 appears later in childhood or adolescence and progresses more slowly, while Type 4 is a rare adult-onset form causing gradual muscle weakness later in life.

In general, the earlier the symptoms begin, the more severe the condition tends to be.

Giovanni Baranello, Professor of Paediatric Neuromuscular Disorders, Honorary Consultant in Paediatric Neuromuscular Diseases at Great Ormond Street Hospital— where Jesy’s twins were diagnosed—told the Daily Mail that SMA exists on a spectrum.

‘Types 2 and 3 develop normally in terms of cognition and are mildly affected,’ he said. 

‘For example, type two can sit, but they cannot walk, and the type three can walk, but they will struggle with jumping, running or getting up from the floor, these kind of things.

‘But for cases of type 1,  they require very intense care and will always remain disabled children.’ 

How SMA-1 affects babies

In babies with SMA-1, muscle weakness is widespread and rapid. Infants may appear unusually floppy due to very low muscle tone and often struggle to lift their head, support themselves or move their limbs.

As the disease progresses, it affects the muscles needed for breathing, swallowing and feeding, as well as the ability to cough and clear mucus from the lungs – leaving babies vulnerable to chest infections and breathing difficulties.

Speaking about her own daughters’ diagnosis, Ms Nelson said early signs included floppiness, an inability to hold themselves up without support, a distinctive ‘frog-like’ positioning of the legs with little movement, and rapid breathing that is noticeable in the tummy.

Jesy with bandmates Little Mix who won X-Factor in 2011

Without treatment, SMA-1 was historically associated with a life expectancy of less than two years, most often due to respiratory failure. Doctors stress, however, that learning and awareness are often unaffected, meaning babies remain alert and responsive despite severe physical weakness.

Professor Baranello said: ‘They are normally very bright and smart babies, and there is a huge contrast between how aware of what is happening around them, and the very limited movements that they may be able to do.’ 

He added that often babies with Type 1 have had a good level of movement in their limbs, but as the disease progresses they lose the ability, becoming floppy.  

‘Some of them cannot move their legs, some of them struggle to keep their head upright and they just keep falling down when the parents keep them on their lap or on their shoulder. 

‘Some of them may struggle sometimes with swallowing, and it’s very important to be very aware of this, because they can have choking episodes.’ 

He added that if a baby has had multiple hospital admissions by the age of four or five months because they are struggling with feeding, or have had a severe breathing infection because of the weakness of their respiratory muscles, it can flag to doctors to investigate for SMA. 

Nelson said she decided to speak publicly in the hope of helping other families spot the warning signs sooner, urging parents to seek urgent medical help if they have concerns.

Experts agree that time is critical – with early diagnosis and rapid treatment offering the best chance of improving long-term outcomes for affected babies.

The early signs doctors urge parents to watch for

Experts say the early symptoms of SMA-1 can be easy to miss – particularly in premature or medically vulnerable babies, where developmental delays are often initially put down to an early birth.

Ms Nelson said the alarm was first raised when her mother noticed the twins were ‘not showing as much movement in their legs as they should be’. The girls later began to struggle with feeding – another key warning sign.

However, because the twins were born prematurely, Nelson and her fiancé were initially reassured that slower development was to be expected, and told not to worry when they first sought medical advice. However doctors say this is a mistake. 

Early signs can include reduced movement in the arms or legs, poor head or neck control, feeding difficulties or weak sucking, shallow or laboured breathing, frequent chest infections and delays in reaching basic motor milestones.

Experts say Jesy Nelson’s decision to share her daughters’ diagnosis could help other families recognise the signs sooner

Nelson said the months leading up to the diagnosis were ‘the most heartbreaking time of my life’, adding that she felt she was grieving the future she had imagined for her children.

Specialists stress that any concerns about muscle weakness or feeding problems in young infants should be urgently assessed, regardless of whether a baby was born prematurely.

Time, they warn, is critical – with early diagnosis and rapid treatment offering the best chance of improving long-term outcomes.

How SMA is diagnosed

If SMA is suspected, doctors confirm the diagnosis using a simple genetic blood test, which checks for changes in the SMN1 gene.

Testing can also identify how many copies of a related ‘back-up’ gene, SMN2, a child has – an important factor in predicting how severe the condition may be and helping to guide treatment decisions.

In some countries, SMA is detected through routine newborn screening. In the UK, screening is currently limited, though campaigners are calling for the condition to be added to the NHS blood spot test.

The treatments offering new hope

Doctors say treatment for SMA has advanced dramatically in recent years.

Several disease-modifying therapies are now available on the NHS, including gene therapy, which delivers a healthy copy of the faulty gene to the body. These treatments can slow or halt disease progression and, in some cases, significantly improve muscle function.

However, timing is critical. Because damage to motor neurons cannot be reversed, treatment works best when given as early as possible, ideally before severe weakness has developed.

Professor Baranello said that the new treatments have added years on to SMA-1 children’s life expectancies, which used to be no more than two to four years. 

‘We can be more optimistic now, we have children with SMA who have been treated for seven, eight, nine years,’ he explained.

‘And some children involved in clinical trials are still alive ten years later. The survival rate has improved massively.

‘If you think that in the past 98 per cent or more of our children before the treatment died, and now the vast majority of them survive and are still alive. It’s a dramatic change, you know, in the landscape.’ 

Alongside drug therapy, babies with SMA-1 require highly specialised care, often involving respiratory support, nutritional management and intensive physiotherapy.

Experts say Jesy Nelson’s decision to share her daughters’ diagnosis could help other families recognise the signs sooner – and access life-saving treatment before irreversible damage occurs.