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Medium chain acyl-CoA dehydrogenase (MCAD) deficiency

Medium-chain acyl-CoA dehydrogenase (MCAD) deficiency stops the body from turning certain fats into energy. The condition can be particularly serious during times of fasting (no eating) or illness.

Symptoms usually begin in the first few years of life and can include low blood sugar, low energy levels and vomiting. More serious symptoms such as seizures, liver and brain problems, coma and sudden death can also occur.

Treatment is focussed on ensuring frequent feeding to avoid prolonged periods of fasting.

Quick facts about medium chain acyl-CoA dehydrogenase (MCAD) deficiency
Genes: ACADM
Inheritance: Autosomal Recessive
Relevant resources for medium chain acyl-CoA dehydrogenase (MCAD) deficiency

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 medium chain acyl-CoA dehydrogenase (MCAD) deficiency inherited?

medium chain acyl-CoA dehydrogenase (MCAD) deficiency 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 condition.

If both parents are carriers of medium chain acyl-CoA dehydrogenase (MCAD) deficiency, there's a one in four chance that their children could develop symptoms.

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 condition in your child. Eugene offers an inclusive genetic carrier screening panel that includes medium chain acyl-CoA dehydrogenase (MCAD) deficiency, 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 medium chain acyl-CoA dehydrogenase (MCAD) deficiency before or early in pregnancy?

The biggest benefit of screening for medium chain acyl-CoA dehydrogenase (MCAD) deficiency 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 condition is low.

Since 90% of children that have a recessive genetic condition like medium chain acyl-CoA dehydrogenase (MCAD) deficiency 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 condition in the first place.