Congenital disorders of glycosylation (PMM2-related)

Congenital disorders of glycosylation (CDGs) are a group of disorders, which cause difficulty making proteins in the body, called glycoproteins. The most common of these conditions is called CDG type 1a, which can lead to a wide range of symptoms. Some of these symptoms include poor muscle tone, difficulty maintaining or gaining weight, having abnormal fat distribution, worsening of the nerve cells in the brain, distinctive facial features and delayed development.

People who are seriously affected by this condition usually start experiencing symptoms in infancy and sadly, have a shortened life expectancy. Unfortunately, there is no cure, but treatment can help manage symptoms.

Quick facts about congenital disorders of glycosylation (PMM2-related)
Genes: PMM2
Inheritance: Autosomal Recessive
Alternative Names: CDGs
Relevant resources for congenital disorders of glycosylation (PMM2-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 disorders of glycosylation (PMM2-related) inherited?

congenital disorders of glycosylation (PMM2-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 disorders of glycosylation (PMM2-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 disorders of glycosylation (PMM2-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 disorders of glycosylation (PMM2-related) before or early in pregnancy?

The biggest benefit of screening for congenital disorders of glycosylation (PMM2-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 disorders of glycosylation (PMM2-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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