Q & A
Spinal muscular atrophy (SMA) is a rare neuromuscular disease that is caused by a genetic mutation in the SMN1 gene. It involves the loss of nerve cells called motor neurons that control muscles. The disease has a progressive course and, unless treated early, invariably leads to the loss of function and a severe physical disability.
Approximately one in 7,000 children in Europe is born with SMA.
Once lost, motor neurons cannot be regenerated, and symptomatic SMA thus cannot be cured. Unless treated early, 50–60% of children born with SMA will experience an acute course of the disease – they will never learn to sit up independently, will require 24/7 respiratory support and mechanical feeding, and will be unlikely to live longer than a few years. SMA remains the leading genetic cause of death in infants and toddlers everywhere where modern treatments are not available.
Fortunately, there are three treatments approved and widely used in Europe that can preserve motor neurons and prevent further deterioration. If these treatments are introduced at the brief presymptomatic stage of SMA, often lasting only a few weeks after birth, the children are likely never to develop symptoms. Instead, they will develop like their healthy peers.
This underscores the need of universal newborn screening in SMA.
Newborn screening, also called neonatal screening, is a diagnostic process in which newborn babies are tested for certain rare genetic and metabolic disorders that may not be immediately apparent at birth, but can cause serious health problems if left untreated. It is performed typically within 24–72 hours and involves a simple blood test, usually drawn from the child’s heel (hence its name: the heel-prick test).
The purpose of newborn screening is to identify and then treat these rare conditions early, allowing for better health outcomes, sometimes saving lives.
Bloodspot-based newborn screening was conceived in the 1950s and 1960s, initially for phenylketonuria. The introduction of fast, inexpensive diagnostic technologies in the late 1990s enabled affordable newborn screening for a larger number of rare diseases. In parallel, new therapies and management paradigms were being approved.
Today, individual European countries screen newborns for between 0 and 40 disorders. The typical number of disorders in modern newborn screening programmes stands at around 20. More ambitious programmes, in place in a handful of European countries and the US, include a bloodspot test for 30 or more disorders. Only a minority include a test for SMA.
People who are diagnosed with SMA on the basis of symptoms will always always experience severe physical disability throughout their lives, including an inability to walk as well as other muscular and orthopaedic complications. This will remain the case even if they quickly start on one of the three approved therapies, which stabilise the disease course.
On the other hand, when these treatments are introduced at the presymptomatic stage of SMA – which lasts from a few weeks to a few years after birth – children are protected from developing SMA symptoms. Instead, they develop like their healthy peers.
For this reason, SMA should be tested for at birth in all children.
Nowadays, several European countries have added SMA to their newborn screening test panel. However many more have not.
Typically, a pilot or pilot study in newborn screening is a research project run in a small number of hospitals whose aims include testing screening protocols, data collection mechanisms, sample strategies, logistics, and so on. Pilot studies are usually conducted in preparation for the routine implementation of newborn screening and are often funded through different mechanisms than routine screening.
At times, national authorities may also call the early phase of a national screening programme, a pilot phase.
The White Paper on SMA Newborn Screening is a major publication of the Alliance that summarises the current state of research and the major reasoning for introducing routine newborn screening for spinal muscular atrophy. It has been authored by a multidisciplinary group of experts affiliated with the Alliance and reviewed by an independent advisory panel.
Introducing newborn screening for SMA mandates a well thought-through process that should take medical, ethical, social and economic context into perspective. The White Paper aims to provide fact-based insights on these aspects. It is thus intended to inform the dialogue about SMA newborn screening that needs to take place between national authorities, healthcare professionals, public health experts, and patient advocacy groups.
The writing and dissemination process was funded in full compliance with the principles of independence and transparency by a multi-stakeholder funding circle that included the following companies: Biogen, Novartis Gene Therapies, Roche, PerkinElmer and LaCAR MDX Technologies.
The White Paper can be downloaded here.
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