Newborn Screening and Fabry Disease: What We Know and Don't Know
Dawn Laney, MS, CGC, CCRC, Emory University:
Fabry disease began testing, its been about five years now, in the state of Missouri and it was sort of added on as an additional test because there was a test panel that you could test from multiple lysosomal storage diseases. And when you test for multiple lysosomal storage these at one time, Fabry disease is kind of tossed in there with the others.
In the United States, usually states think about what to put on their newborn screening panel based on what's on the RUSP, which is short for recommended uniform screening panel and that's a panel at the government level and different diseases are nominated and then the evidence is reviewed and if it's determined that it may make a big difference to screen for a particular condition it gets put on that screening panel and then states can choose to do it or not.
So, when talking about Fabry disease, it is not on the RUSP at this time. That doesn't mean it shouldn't be screened for, it just means that they haven't done an evidence review and decided that it's an important thing to add to this recommended uniform panel. So, the only states that are doing it (Fabry screening) are states that legislated it specifically and it is usually associated with another panel as an add-on test.
When you look at Illinois and you look at Missouri, you figure those the 3 states that across the whole state is screened for Fabry.
There is a pilot project which is a smaller scale for four hospitals— it's done in New York and they're about to start in several other states, Pennsylvania, New Mexico, there's some other ones out there as well. But again, it's not on the uniform panel so not many states automatically decide to put it on when they do it's usually because of patients requests or families requests to put it out and they're because they're interested in getting earlier diagnosis.
What we've learned from newborn screening for Fabry disease is some very important information. The first thing we actually learned was from newborn screening done in Taiwan. We learned that there are some mutations that are much more common than we ever thought they were. And we have to figure out, if you've got a mutation that's not family specific, that's more globally in one particular area of the country, how do you figure out when that will have symptoms, how do you figure out the best time to treat? We know what to do when someone has a classic Fabry disease mutation— one that starts in childhood. We know that we have to treat early so that we can avoid end organ damage as we go further in the disease course.
When we talk about what we call a non-classic or a later onset mutation, they are still going to have health problems in most cases but how do you know when to start treatment. Do you start as a child? Do you start someone later or when they are an adult? We want to start treatment before there's end organ damage but we know every child that's born with Fabry disease, they already have potential to have symptoms but who's going to have more? Who's going to have less? Do you start treatment on a two-year-old? Do you start treatment on a ten-year-old? How late is too late to avoid kidney failure, heart attacks, and strokes.
From newborn screening, we have learned that there's a lot more we need to know but we do know what to do when somebody has symptoms in the classic form— so the good news is if you have the most severe form of Fabry disease identified in the family based on newborn screening, we know what to do. If you've got a more moderate form or an unusual form, then we're still working on it but I think the most important lesson we've learned about Fabry disease is, it's much more common than we thought particularly in the non-classic form.