Mitochondrial DNA depletion syndrome (MDS) affects the mitochondria - the structures that produce energy for cells.
Mitochondria contain their own DNA, known as mitochondrial DNA (mtDNA). Having adquate amounts of mtDNA is essential for normal energy production within cells. Patients with MDS have low levels of mtDNA in specific tissues of the body.
Symptoms of MDS begin in the first few weeks of life and include vomiting, diarrhea, and poor growth. Liver disease typically follows and leads to liver failure in infancy. Neurological problems, including developmental delay, low muscle tone, muscle weakness, difficulty walking and coordinating movements and seizures are also common.
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.
mitochondrial DNA depletion syndrome 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 mitochondrial DNA depletion syndrome, there's a one in four chance that their children could develop symptoms.
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 mitochondrial DNA depletion syndrome, 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
The biggest benefit of screening for mitochondrial DNA depletion syndrome 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 mitochondrial DNA depletion syndrome 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.