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Making the Rare Diseases Rarer?

ImageOver the past week, I received two emails from parents of children with severe and rare genetic diseases. Both emails were very heartfelt and informative. One of the emails ended with this plea: Can you add this disorder to your list and maybe prevent some suffering?

Currently, the PJGH is offering screening for 18 diseases that have known ‘founder mutations’ in the Ashkenazi Jewish (AJ) population.  In addition to these 18 diseases, the PJGH also offers screening for 2 other common diseases that do not have AJ founder mutations. Genetics centers around the country have different opinions when it comes to adding on more tests to the core 18 AJ diseases (and I encourage you to do your research when you decide which panel to use). But the overall consensus is that genetic counseling should accompany any genetic testing that goes on, and not all diseases on a panel are created equal.

So how do I respond to the father of a child with a devastating genetic disease that is not included in the core panel? Certainly he has a point- he and his family have suffered immensely and he wants to help others avoid going through the same thing. However, to be perfectly blunt, there are tons of terrible diseases out there, and the genetics professionals just cannot test for each and every one on the population level. If geneticists have identified a mutation in the affected individual, then it’s a different story and genetic testing of other current and future family members is much more feasible.

So why can’t we test on the population level? Well, for starters, we do not (yet) know about the causative mutations for each and every genetic disease. Also, the methods of accurate testing may differ from disease to disease, and the detection rate may not be as high as we would like for each of these diseases (so someone who tests negative for something may have a false sense of security).

To be most efficient, we now test for the common diseases that have known founder mutations, whose natural history is understood and is severe, and whose testing has a high rate of detecting carriers instead of missing them.  It is hard for me to tell parents of kids whose diseases do not meet these criteria that we cannot add them to our panel because it makes it sound like their diseases are not as “significant” or “bad” as the ones we do include on the panel.  This is absolutely not true.

In the future, more sophisticated technologies such as whole genome sequencing may change this. Such methods of testing are already being used to classify rare diseases in children. But at this point, it’s just not reasonable. I wish we could test for everything and avoid heartache, but for now, we need to stick to what makes the most sense.

There are resources out there for people with rare disorders and their families. Be sure to check out:

The National Organization for Rare Disorders

The Office of Rare Disease Research (helps recruit individuals with rare diseases for research studies)

Rare Disease Day (an international advocacy day to bring widespread recognition of rare diseases—always celebrated at Einstein and around the world on the last day of February every year , a particularly rare day if it’s a leap year!)

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