Sub Subramony, MD, discusses how Friedreich’s ataxia onset and progression affects pediatric populations differently from adults, and how this impacts treatment.

Friedreich’s ataxia is typically a disease of children beginning in around 9, 10, 11 years of age or even 12. But there is a substantial number that affects — begins the process in — adult life anywhere from 20, 30, 40 years of age as well.

In children, in general, the earlier the onset of the disease, the faster the progression. And they tend to decline faster.

And again, the earlier onset is related to the fact that the repeat expansion, the GAA expansion, is of a larger size and that leads to earlier onset, whereas with the later onset disease, the expansion size tends to be smaller.

Though there is no strict correlation, you cannot predict the age of onset looking at the expansion size in a blood test. But what it also means is that the larger expansions are also associated with some of the other things that happens in Friedreich’s ataxia. Cardiomyopathy, for example, often is more common in patients with larger expansions.

So we know, for example, that many patients with Friedreich’s ataxia who begin in childhood have a greater likelihood of having a cardiomyopathy, typically what we call a hypertrophic cardiomyopathy, which is an enlargement of the muscle thickness of the heart in various regions, like the septal wall and the posterior wall thickness, it goes up.

This tends to be less likely in adult-onset disease as well. Now, obviously a lot of the children will eventually grow up into adults, so they’ll carry on with all the problems that are associated with childhood onset of the disease.

So, again, you need more monitoring and more careful management of multiple problems in children, which is less definitely of an issue in adults, but nevertheless all of these patients require multidisciplinary care.