Pregnancy & The Spinal Muscular Atrophy Test

SMA, otherwise known as Spinal Muscular Atrophy is one of a number of prevalent genetic conditions that can be effectively tested for prior to a pregnancy. This gives parents to be a chance to find out whether or not their child can inherit this disease, a concern which might have a major impact on whether or not they decide to go ahead with a pregnancy.

What is SMA?

Spinal muscular atrophy involves a muscle weakness around the spine caused by a genetic defect which can potentially be passed on from parent to child. The muscle weakness involved in the diseases results in a progressive loss of movement over time.


SMA affects a class of cells called motor neurones, or motor nerves. These are responsible for carrying the message from your brain to your muscles which triggers movement. People who suffer from SMA have a defective gene which means that their motor neurons around particular areas of the spine can’t survive, impairing the function of muscles in that area and ultimately causing the muscular weakness typical of the disease.

Over time SMA causes a gradual loss of mobility, and while the disease varies in severity, it can have a debilitating effect on sufferers of all ages. Spinal muscular atrophy is one of the most common causes of infant muscular death, and is an autosomal recessive disease, meaning that the genes causing the illness must be present in both parents for there to be any chance of SMA being passed on.

As a leading cause of infant death, SMA is a concern to many parents to be who have had a family history of spinal muscular atrophy. As such screening for the genes causing the illness in both partners can be a good way of finding out whether or not there is a chance of a child inheriting a particular neurodegenerative disease.

How can I test for SMA?

As an autosomal recessive disease as mentioned above, both parents need copies of the defective SMA gene for it to affect their child. As such if you are considering a screen for the disease causing gene, it is probably more useful to have your partner tested as well, thereby giving you an accurate idea of whether or not you have the gene and whether or not said gene can be passed on.

The Alef8 test is an example of a genetic screen which tests for SMA. Alef8 also looks for a number of other illnesses (8 in total) which are common concerns for parents thinking about conceiving but worried about genetic disease impeding on the quality of their future child’s life.

Where can I test for SMA in the UK?

SMA can be tested for either privately or through the NHS, in either instance all that you need to provide is a blood sample on which the test can be run. Because of the many benefits genetic screens offer, the NHS now provides testing and support from trained clinical geneticists in regional centres across the UK.

Private testing offers the benefit of a quicker service, but if you would rather go down the NHS route then talking to your GP about a referral to your nearest regional genetics service is the first step towards being tested and finding out about whether or not you can possess the genes for SMA.

SMA is thought to be carried by 1 in 60 people, while only about 4 people in every 100,000 actually suffer the disease. As this is the case you can take comfort in the fact that statistically speaking the likelihood of both yourself and your partner carrying the necessary genes for the disease, and then passing said gene down to your offspring, is fairly small. Taking the test is a good way to make sure and give yourself the peace of mind.


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