Children of gene carriers have a 50% chance of being a gene carrier themselves (for an explanation why - read more here). Some people choose to have children the natural way and take the odds, others decide to make sure their children can not carry the gene.
There are several ways to make sure an embryo does not carry the DCAA gene.
Chorionic villus sampling
Chorionic villus sampling (CVS) is done while you are already pregnant and checks if the baby carries the DCAA gene. A small sample of the placenta is taken using a slender needle inserted through the abdomen, and the sample is then examined in a laboratory. If the baby carries the gene, you might decide to have it removed. For more information about the procedure in English - read more here. Procedures may different in various countries.
Preimplantation genetic diagnosis (PGD)
Some people chose to undergo PGD. During this procedure the parent that has a 50% chance of carrying the DCAA gene undergoes genetic testing. When the test turns out to be positive, and the parent is a gene carrier, PGD is an option. During this procedure an artificial fertilization (as opposed to a natural one) is established. Once the embryo consists of a cluster of eight cells, one cell is removed for examination. The DNA from this cell is tested for any abnormalities. Then one or two healthy embryos (without any irregularities) are placed back into the uterus. The remaining embryos are destroyed in accordance with a legal protocol. The genetic preparation preceding the abovementioned procedure last for roughly year and is followed by fertility treatment (IVF).
This procedure might differ in different countries. Your GP might be able to give you more information. You can read more about PGD in English here.
Exclusion- prenatal diagnostics or PGD
Sometimes a parent who is a 50% risk carrier for DCAA chooses not to get tested for the gene. In that case exclusion PD or PGD is possible. This means that the DNA of the fetous (PD) or embryo (PGD) is tested. When the fetous or embryo carries the allele (for more info about who genetics work - click here) of the healthy grandparent it is a 100% sure that it does not carry the gene for DCAA. However, if the embryo or fetous has the "sick" grandparent's allele, there is a 50% that the baby has DCAA. In that case, parents may choose to end the pregnancy. The availability for exclusion PGD or PD differs per country. Talk to it about your GP or to a clinical geneticist.