Glycogen storage disease type IV/adult polyglucosan body disease

Glycogen storage disease type IV (GSD-IV) can affect a person's ability to break down glycogen - a complex sugar found in muscles. A build-up of glycogen can cause liver and muscle damage, which can lead to weak muscles, liver disease and a weak heart (also called cardiomyopathy). The age symptoms start and how serious the condition is can vary from person to person. The most serious symptoms can cause death early on in life. In milder forms, people with GSD-IV can survive into adulthood.

Adult polyglucosan body disease (APBD) is caused by variations in the same gene that affects the nervous system. Symptoms of APBD generally begin in adulthood, between the ages of 40 and 60 and include problems with bladder control, reduced feeling in the legs and muscle weakness. These symptoms usually get worse over time and can lead to the need for a wheelchair.

Quick facts about glycogen storage disease type IV/adult polyglucosan body disease
Genes: GBE1
Inheritance: Autosomal Recessive
Alternative Names: Adult polyglucosan body disease, GSD-IV, APBD
Relevant resources for glycogen storage disease type IV/adult polyglucosan body disease

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 glycogen storage disease type IV/adult polyglucosan body disease inherited?

glycogen storage disease type IV/adult polyglucosan body disease 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 glycogen storage disease type IV/adult polyglucosan body disease, 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 glycogen storage disease type IV/adult polyglucosan body disease, 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 glycogen storage disease type IV/adult polyglucosan body disease before or early in pregnancy?

The biggest benefit of screening for glycogen storage disease type IV/adult polyglucosan body disease 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 glycogen storage disease type IV/adult polyglucosan body disease 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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