Methylmalonic acidemia with homocystinuria, cobalamin C type affects the way vitamin B12 is metabolised. The signs and symptoms of this combined condition usually develop in infancy, although they can begin at any age.
When the condition begins early in life, children often have an inability to grow and gain weight at the expected rate (failure to thrive), which is sometimes recognized before birth. Children who are affected can also have difficulty feeding and a pale appearance related to anaemia. Most infants and children with this condition have an unusually small head size (microcephaly), delayed development, intellectual disability and weak muscles. The late-onset form may present with neurological symptoms first. Early initiation of treatment may delay onset or reduce the severity of symptoms. Without treatment, symptoms can be life-threatening.
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.
methylmalonic acidemia with homocystinuria, cobalamin C type 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 methylmalonic acidemia with homocystinuria, cobalamin C type, 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 disease in your child. Eugene offers an inclusive genetic carrier screening panel that includes methylmalonic acidemia with homocystinuria, cobalamin C type, 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 methylmalonic acidemia with homocystinuria, cobalamin C type 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 methylmalonic acidemia with homocystinuria, cobalamin C type 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.