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People who are affected with cystinosis experience a build up of cysteine (an amino acid) in the cells of their body. This excess cysteine forms into crystals that can damage organs and tissue, particularly the kidneys and eyes.

There are three types of cystinosis, which vary in age of onset and severity. In the most severe and most common form (95% of cases), babies can develop soft, bent bones, progressive kidney damage and struggle to put on weight. They also experience eye pain, and sensitivity to light often develops by the age of 2 since crystals form in the eye.

If left untreated, kidney failure usually occurs by age 10. However, with treatment, individuals with the severe form often live into into their 40s to 50s. The less severe forms of the condition cause symptoms to begin later in life and sometimes do not affect the kidneys.

Quick facts about cystinosis
Genes: CTNS
Inheritance: Autosomal Recessive
Relevant resources for cystinosis

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.

Learn more about genetics

How is cystinosis inherited?

cystinosis 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 cystinosis, 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 disease in your child. Eugene offers an inclusive genetic carrier screening panel that includes cystinosis, 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.

Learn more about carrier screening

Should parents screen for cystinosis before or early in pregnancy?

The biggest benefit of screening for cystinosis 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 cystinosis 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.