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Spinal muscular atrophy (SMA) is a rare genetic disorder that affects the part of the nervous system that controls muscle movement.
SMA affects the motor nerves (neurons) of the spinal cord. Usually, when we want to move our body, motor nerves send the message from our brain to our muscles, telling the muscles to move. In children with SMA, these messages do not reach the muscles. This causes muscle weakness, muscle damage,
muscle wasting (atrophy) and eventual loss of function.
Children with SMA may have difficulty crawling, sitting, walking and moving their limbs and neck. Their ability to breathe and swallow may also be affected.
SMA is a very complex disorder, affecting each child differently. There are three common types of SMA affecting children.
How SMA affects a child depends on when the disorder first causes symptoms. Early signs of SMA include:
The symptoms of SMA are progressive, which means that they get worse over time. The muscles of the limbs and chest become weaker, gradually making breathing more difficult. Weakness of the breathing muscles is the most serious complication of all forms of SMA, especially in children.
It is important to note that SMA does not affect all parts of the body. Intelligence is unaffected and children with SMA attend mainstream schools.
If your child shows any signs or symptoms of SMA, or you are concerned that your child is not reaching their motor milestones, see your Maternal and Child Health Nurse or GP. You may be referred to a paediatrician or paediatric neurologist.
Currently there is no cure for SMA, but there are many ways to help your child. Your child will be under the care of a team made up of different medical professionals.
In the past, the treatment of SMA has been based on management of the complications of weakness, feeding problems and breathing difficulties. However, there are some new medications that in recent years have been proven to improve strength, motor function, breathing and feeding in
children with SMA. These medications should become increasingly available in the future and will change the focus of SMA management.
Medical care for children with SMA aims to prolong survival and improve quality of life.
SMA can be very difficult for families to deal with. Your multidisciplinary care team has a lot of experience in helping families and children cope with diseases like SMA, and they can also put you in touch with other families in a similar situation. This can be a great source of comfort
Spinal Muscular Atrophy Australia and
Muscular Dystrophy Australia provide support, assistance and information for people and families affected by SMA.
While the internet can be a source of good information, it can also be a source of false hope and inaccurate information. Be cautious of misleading claims about treatments that promise to 'cure' your child's SMA. Rely on your doctor for expert and professional advice.
SMA is a genetic condition caused by a mutation (change) in the survival motor neuron (SMN) gene. Parents of children with SMA have no signs or symptoms themselves and are generally not aware that they carry the mutated SMA gene until they have a child with SMA. If both parents are
carriers, their children each have a one-in-four chance of inheriting SMA.
Couples with a family history of SMA can have prenatal genetic testing to determine if an unborn child has SMA. Talk to your obstetrician, neurologist or geneticist about this.
What is the long-term outlook for a child with SMA?
SMA progresses differently for each child with the disorder. The severity usually depends on the type of SMA your child has. SMA type 1 is the most serious; children with this form of SMA have a significantly shortened life expectancy.
How far off is a cure for SMA?
Although no cure currently exists for SMA, research is currently underway. Researchers, doctors and families hope to find effective treatments for this disorder in the near future.
Developed by The Royal Children's Hospital Neurology department with input from Muscular Dystrophy Australia. We acknowledge the input of RCH consumers and carers.
Reviewed September 2018.
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