An efficient and straightforward test is now available that could provide families with early information on SMA Type 1, a critical genetic disorder, potentially revolutionizing how it is diagnosed and managed.
There has been a surge in awareness about SMA Type 1, especially after Jesy Nelson disclosed that her twins were diagnosed with this genetic disorder, underscoring the need for early detection and intervention.
The former member of Little Mix welcomed her daughters, Ocean Jade and Story Monroe Nelson-Foster, in May 2025.
Nelson experienced a challenging pregnancy, as she was diagnosed with Twin-to-Twin Transfusion Syndrome (TTTS) at the age of 34, necessitating surgical intervention.
TTTS is described as a ‘rare disorder that affects identical twin pregnancies’ and occurs when two babies share a placenta in the uterus. This condition results in unequal blood flow to the babies, posing risks such as premature birth, neurological and heart damage, and can be life-threatening.
The twins were born early and spent approximately a month in the NICU.
On January 4th, Nelson shared a heartfelt video on social media, revealing her daughters’ diagnosis of SMA Type 1.
Nelson recounted that her mother observed the girls’ limited leg movement, prompting a series of medical consultations and tests, which ultimately led to the diagnosis of SMA.
“After the most gruelling three to four months and endless appointments, the girls have been diagnosed with a severe disease called SMA type one,” Nelson shared.
“It stands for Spinal Muscle Atrophy which affects every muscle in the body from legs, arms, swallowing.”
This genetic disorder causes progressive muscle weakness, as explained by the Cleveland Clinic.
“Over time, it kills the muscles in the body. If it’s not treated in time, your baby’s life expectancy will not make it past the age of two,” Nelson added.
“Once the girls got treated, it was a very rapid process. Time is of the essence with this disease.
“When they assessed the girls at Great Ormond Street, we were told they were never going to be able to walk. They would probably never regain their next strength. They will be disabled. The best thing we can do right now is to get them treatment and hope for the best.”
A genetic test is available to diagnose infants with this condition, highlighting the significance of early detection. For newborns, the test involves a simple heel prick, akin to standard newborn screenings. This blood sample is then analyzed in a lab for mutations in the SMN1 gene, which is responsible for SMA Type 1.
Identifying the condition early can significantly impact life expectancy and quality, as treatments are most beneficial before symptoms manifest.
In the United States, newborn screening for SMA, including SMA Type 1, is now incorporated into routine newborn screenings.
In 2018, SMA was included in the U.S. Recommended Uniformed Screening Panel (RUSP). By 2024, all 50 states in the U.S. conduct SMA screenings, as reported by the nonprofit organization Cure SMA.
In contrast, routine newborn screenings for SMA are more prevalent in the United States compared to the UK and much of Europe. In the UK, SMA is not yet part of the NHS standard newborn blood-spot screening panel, according to SMAUK, the leading UK charity supporting individuals and families affected by Spinal Muscular Atrophy.
In the UK, when babies reach five days old, the NHS performs a routine blood-spot test via a small heel prick to screen for nine rare but serious conditions. However, SMA is not included in this list.
SMAUK indicates that SMA is a leading genetic cause of infant mortality in the UK. Without treatment, approximately 90% of babies born with SMA Type 1 will either pass away before their second birthday or require lifelong ventilation support.
The UK National Screening Committee (UK NSC) is actively reviewing the inclusion of SMA in screenings, with pilot studies in progress as of 2026.