Newborn babies can have some heart-breaking illnesses, for which there are no treatments. Spinal muscular atrophy used to be one of them, with ­babies rarely living longer than two years old.

But now there’s new hope for SMA – gene therapy. Costly though it is, £1.8million for the one-off jab, it promises to give babies the ability to sit, crawl and walk. Without it, they might lie motionless.

For babies with SMA, which is the leading genetic cause of death in ­children, the drug can mean normal development and a longer life.

The drug, Zolgensma, is priced at £1.79million per dose, and has been available on the NHS since March after a deal was struck with manufacturer Novartis Gene Therapies.

As many as 80 babies and young children a year could benefit from the life-changing gene therapy.

Babies born with Type 1 SMA, which is the most common, have ­paralysis, progressive muscle weakness, loss of movement and difficulty breathing.

But studies found that a single ­treatment with Zolgensma has helped them not only sit, crawl and walk but also be able to breathe without a ­ventilator and live longer.

Arthur Morgan, who was in the news recently as the first baby in the UK to be given the drug, was born six weeks premature in December and diagnosed with SMA at three weeks. He had the gene therapy administered into a vein when he was five months.

Four specialist NHS centres will be administering the treatment, including Evelina London Children’s Hospital, where Arthur was treated.

The others are Manchester ­University NHS Foundation Trust, Sheffield Children’s NHS Foundation Trust and University Hospitals Bristol and Weston NHS Foundation Trust.

Dr Elizabeth Wraige, consultant paediatric neurologist at Evelina London Children’s Hospital, said: “This treatment will bring hope to families affected by SMA who have fought so courageously against it.”

She confirmed some of the children in the original clinical trials of Zolgensma are now over five years old.

NHS chief executive Sir Simon Stevens added: “It is fantastic news that this revolutionary treatment is now available for babies and children like Arthur on the NHS.

“The NHS Long Term Plan is committed to securing cutting-edge treatments for patients at a price that is fair to taxpayers.

“Zolgensma is the latest example of the life-changing therapies the NHS is now routinely using to transform the lives of patients and their families.”

Cost shouldn’t stop a baby from having life-changing treatment.