The question of whether dyscalculia can be cured comes up regularly and is often answered with a great deal of misinformation.
The problem is actually with the semantics of the question and the definition of dyscalculia.
Definition of Dyscalculia
Dyscalculia is very broadly defined as a specific learning disability which affects math. The definition tells us nothing of a specific area of the brain affected. The truth is that neuroscience is nowhere near understanding the inner workings of the brain. There are many useful models of how the brain functions. However they are only models and are not accurate. For example, the theory that specific parts of the brain have specific functions is useful but not accurate. In certain activities certain parts of the brain will be more active. This can be shown on FMRI scans.
However, as much as we'd like to say that a specific area is "doing math" this is not actually possible because many other areas of the brain will also be involved. It is true that when some areas of the brain are damaged through injury, stroke, or surgery, that will affect certain skills. Early on this led to the belief that certain areas are responsible for certain skills. Yet that is only partially true. Sometimes these skills return while the damage remains. The brain remaps itself. This is called neuroplasticity. The neural connections in the brain change. The brain can also grow new neurons. This is called neurogenesis.
Up until recently it was believed that brains did not change. That we were stuck with the brain we were born with. Or if a brain was injured it could not heal. This was actually disproven in 1936 but was not accepted by most neuroscientists until the 1990's. Now that it has been accepted it is the hottest topic in neuroscience.
Unfortunately the old beliefs have stuck around and are still being promoted in many circles.
Because dyscalculia is not specifically defined and because there is no place in the brain we can look at and say "Yep that's dyscalculia", there is no way of saying dyscalculia can or cannot be cured.
It is true that there is no medication for it. Nor should there be. Mediations are not effective at neural development. Despite many being marketed as such.
So the question itself is flawed.
The question should really be:
"Can someone with dyscalculia improve their brain and therefor develop better math skills?"
The answer to that is a resounding yes. Find out how to do it here.