Spinal muscular atrophy: The top genetic killer of infants under two

Anastasia Tsirtsakis

14/07/2020 4:21:50 PM

The RACGP is offering new accredited training to help upskill GPs to recognise the warning signs for spinal muscular atrophy.

Young baby
One in 35 people in Australia is a carrier of the gene for spinal muscular atrophy.

When their baby was just 10 weeks old, Rachael Casella and her husband received a devastating diagnosis: their daughter Mackenzie had spinal muscular atrophy (SMA) type 1, a genetic neuromuscular disorder.
At seven months and 11 days old, Mackenzie passed away.
What added to their pain was the discovery that simple genetic screening offered through their GP – either a mouth swab or blood test – could have informed the parents that they are both carriers of the gene. 
‘We felt really angry for a long period of time,’ Mrs Casella told newsGP.
‘We went above and beyond when it came to preparing for a pregnancy … the fact that this test wasn’t offered to us, we were really angry.  
‘It meant that our daughter had to suffer, and we had to suffer.’
While SMA is considered rare, one in 35 people in Australia is a carrier of the gene. However, much like the Casellas, most people will not know that they are carriers until they have their first child, Professor Jon Emery, a GP and adviser for the RACGP’s new SMA education campaign, told newsGP.  
‘Although genetic conditions are still individually rare, they contribute to quite a significant cause of severe disability and early death in children,’ he said.
‘Particularly conditions like SMA.’
SMA is the most common genetic disorder resulting in infant mortality under the age of two.
The disorder is characterised by progressive muscle weakness and wasting due to the degeneration of motor neurons, affecting muscles in the arms and legs, as well as those that control breathing and swallowing.
But a lack of awareness, Professor Emery says, means cases can be dismissed as slight delays in reaching milestones, resulting in delayed referral and diagnosis.
‘The important thing is that their cognition is unaffected, so these are bright and alert children,’ he said.
‘They don’t have dysmorphic features of other types of genetic conditions, and so often this is part of the reason that they may be dismissed to begin with.
‘Key red flags [include] a floppy, weak child – essentially a child with progressive muscle weakness, particularly proximal muscle weakness.
‘[Also] hypertonia. There’s this classic sign of what’s called the “frog leg posture”. So their legs [are] a bit like a frog’s legs when they are lying down due to being hypertonic, and [they] often have weaker head control. So their heads lag when they’re pulled up to sit, and reduced tendon reflexes.’

While there is currently no known cure for SMA, progress has been made, with a new treatment called nusinersen shown to improve outcomes recently listed under the Pharmaceutical Benefits Scheme (PBS).
‘For any condition like this, it is of course devastating for the family, and the fact that we now have this new treatment for SMA I think that at least gives hope to the family,’ Professor Emery said.
‘This highlights the importance of early detection of these children so that treatment can be started as promptly as possible, and reduce and slow down the progression of neuron loss.’

Professor Jon Emery was an adviser for the RACGP’s new SMA education campaign.

To help raise awareness about SMA and other paediatric neuromuscular disorders, as well as promote genetic carrier screening, the RACGP has launched a new education campaign for GPs, funded by the Department of Health.
Professor Emery says early referral and diagnosis will ensure timely treatment, which may delay disease progression and improve outcomes.
‘That’s why early detection is an important part of this campaign, so that those children who are born with the condition are started on treatment as soon as possible,’ he said.
‘But also [so] the family are then provided with the broader multi-disciplinary support. It’s often at that point that genetic counseling has been offered to those couples because, of course, they then have a one in four chance of having another affected child in the future.’
Since Mackenzie’s passing in October 2017, the Casellas have made it their mission to raise awareness about SMA, including lobbying the Federal Government to make genetic testing routine, and covered by Medicare.
As part of their efforts, $20 million was committed from the Medical Research Future Fund to Mackenzie’s Mission, a three-year pilot study that will screen 10,000 couples around Australia for more than 700 genetic conditions. It aims to determine the evidence for making free reproductive genetic carrier screening available to all couples in Australia who wish to have it.
‘It’s incredibly life altering and completely shattering to have your child pass away. What the Australian Government has done is they’ve given our daughter a legacy,’ Mrs Casella said.
National guidelines recommend that carrier screening for SMA, cystic fibrosis and fragile X be offered to all women or couples planning a pregnancy, or in the first trimester of pregnancy, regardless of family history or geographic origin.
While it can be a sensitive topic for GPs to broach, reflecting on her lived experience, Mrs Casella says it is an essential discussion to have.
‘There’s no other way to put it other than essential,’ she said. ‘You only really need to ask a simple question to be able to start this conversation: “Are you planning on having children?”
‘I think we’re fearful for no reason, because you’re only laying out the options. But it’s the GPs’ responsibility to know those options. That’s part of their role.’
Accredited training for GPs
As part of the RACGP’s education campaign, information and resources on SMA and carrier screening have been made available through a dedicated website.
There are two modules of accredited training to help GPs and other health professionals to understand the red flags and help with the initiation of conversations around carrier screening for hereditary rare diseases.
Developed in consultation with other medical organisations, including the Royal Australian and New Zealand College of Obstetricians and Gynaecologists and Spinal Muscular Atrophy Australia, both modules take an hour and have been accredited by the RACGP for two CPD points.
‘This education campaign will upskill GPs across the country so they can spot the warning signs of spinal muscular atrophy,’ Professor Emery said. ‘So more patients can benefit from early referral, diagnosis and treatment.
‘Early detection makes a huge difference both to the individual child and to their family.’
Log in below to join the conversation.

genetic carrier screening spinal muscular atrophy

newsGP weekly poll What areas of healthcare were you hoping would get more funding in this year's Federal Budget?

newsGP weekly poll What areas of healthcare were you hoping would get more funding in this year's Federal Budget?



Login to comment

Dr Tatiana Cimpoesu   15/07/2020 11:15:49 PM

It is terrible for parents and for the affected children but how can we offer genetic screening for all possible genetic disorders?!

Dr Yamile Edid Caro Avila   7/11/2020 2:36:23 PM

Great article to help create awareness