Congenital myasthenic syndrome (RAPSN-related)

Congenital myasthenic syndrome (CMS) is a variable condition that mainly affects the muscles and usually begins in early childhood. People with this condition often have muscle weakness in their face, eyes and other parts of the bodies. Movements such as chewing, swallowing, blinking, crawling, walking, breathing and feeding can be difficult and in very serious cases can be life threatening.

Quick facts about congenital myasthenic syndrome (RAPSN-related)
Genes: RAPSN
Inheritance: Autosomal Recessive
Relevant resources for congenital myasthenic syndrome (RAPSN-related)

A quick genetics rundown

As humans we have about 23,000 genes. These genes are like tiny instruction manuals that influence our health, growth and development. We inherit half of our genes from our biological mum and the other half from our biological dad. These genes are lined up on structures called chromosomes. Most of us have 23 pairs of chromosomes. The first 22 pairs are called autosomes and for the most part - these are the same among men and women. The 23rd pair determine our sex - two X chromosomes for a female and one X and one Y chromosome for males.

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How is congenital myasthenic syndrome (RAPSN-related) inherited?

congenital myasthenic syndrome (RAPSN-related) is known as an autosomal recessive condition. For autosomal recessive conditions, if a person has a variation in one copy of their gene, they are a carrier. This means that they are healthy because they also have a working copy of the gene. But, they can still pass their non-working copy to their child.

If the other parent also happens to be a carrier of the same gene, there is a 25% (1 in 4) chance that they both pass this gene variation on to their child — and as such, have a child affected by the disease.

If both parents are carriers of congenital myasthenic syndrome (RAPSN-related), there’s a one in four chance that their children could develop symptoms.
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What is carrier screening?

Carrier testing is like a checkup for your genes. It tests to see if you carry a gene variation that could cause a serious genetic disease in your child. Eugene offers an inclusive genetic carrier screening panel that includes congenital myasthenic syndrome (RAPSN-related), but there's a total 301 conditions that can be tested.

Eugene’s carrier test is a clinical grade test that can be done from the comfort of your own home — it’s just a saliva test. You're also paired with a genetic counsellor who provides mindful support and guidance every step of the way.

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Should parents screen for congenital myasthenic syndrome (RAPSN-related) before or early in pregnancy?

The biggest benefit of screening for congenital myasthenic syndrome (RAPSN-related) is that it can help future parents understand their reproductive risk so they can be ready and empowered to make more informed decisions. If neither partner are carriers, it provides reassurance and peace of mind that the risk of having a child with a genetic disease is low.

Since 90% of children that have a recessive genetic disease like congenital myasthenic syndrome (RAPSN-related) had no previous family history of it, it often feels completely out of the blue for the parents. Getting screened is a way to know this risk in advance, which can help familes manage or even prevent the disease in the first place.

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