Alport syndrome (COL4A4-related)

Alport syndrome is a condition that affects the kidneys, eyes and hearing. Alport syndrome can be caused by several genes and inherited in different ways; one of those genes is COL4A4.

People who inherit two variations in the COL4A4 gene have autosomal recessive (AR) Alport syndrome. People affected by AR Alport syndrome have high levels of protein and blood in their urine (hematuria), which over time can lead to kidney failure. Hearing loss due to damage of the inner ear typically presents in late childhood, while eye lesions tend to develop in the 20s or 30s. Fortunately these do not usually impact vision.

Certain gene variations can cause autosomal dominant (AD) Alport syndrome. This means inheriting only one variation in the COL4A4 gene is enough to cause symptoms. Individuals affected by AD Alport syndrome tend to have symptoms that are milder and develop later in life than those with AR Alport syndrome. Eye lesions are also rare in AD Alport syndrome.

In all cases, treatment is focussed on managing individual symptoms.

Quick facts about Alport syndrome (COL4A4-related)
Genes: COL4A4
Inheritance: Autosomal Recessive
Relevant resources for Alport syndrome (COL4A4-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 Alport syndrome (COL4A4-related) inherited?

Alport syndrome (COL4A4-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 Alport syndrome (COL4A4-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 Alport syndrome (COL4A4-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 Alport syndrome (COL4A4-related) before or early in pregnancy?

The biggest benefit of screening for Alport syndrome (COL4A4-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 Alport syndrome (COL4A4-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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