Orphan Diseases: Calling All Volunteers
by Sharon Begley
Newsweek Magazine
No child should be born into this world with Batten Disease, which—and here I’ll just quote from the National Institutes of Health—causes “mental impairment, worsening seizures, and progressive loss of sight and motor skills. Eventually, children with Batten disease become blind, bedridden, and demented. Batten disease is often fatal by the late teens or twenties.” And if Mark Chandler has his way, no more will be.
Chandler is chairman and CEO of Biophysical Corp., a pioneering company that, as I wrote about two years ago, offers a battery of tests for “biomarkers” that can indicate the presence of early-stage disease before symptoms appear. (The virtue of testing for biomarkers rather than disease genes is that with the former you are testing for the presence of the actual disease, but with DNA tests you are almost always testing for the possibility of developing a disease in the future.) Now Chandler is hoping to offer tests to identify carriers of rare genetic disorders such as Batten Disease: as carriers, they would not have the disease and so would have no idea they carry silent genes for it until, tragically, their child is born with one of these 1-in-a-million disorders. A genetic test could warn them.
The model is what the Ashkenazi Jewish community has done, beginning in 1969, to screen couples for Tay-Sachs disease, which was more common among that population than Americans generally. If both a husband and wife carried the rare mutation, they were counseled to avoid having children, or (if they had not yet married) even to find other partners, since if two carriers mate their children have a 25 percent chance of having the disease. As a result of the widespread screening, Tay-Sachs has been almost eliminated in American Jewry; of the 20 or so children born with Tay-Sachs in the U.S. each year, most are from Louisiana’s Cajun community or are French-Canadians, two population groups that also carry the mutation.
It may seem like overkill to test all couples or would-be couples for diseases that are so rare, but Chandler thinks he can develop a test for the 400 or so “orphan,” diseases such as those on the list of the National Association for Rare Disorders. All are autosomal recessive: if you inherit the mutation from one parent, and therefore have one copy of the disease gene, you do not develop the disease but are a carrier; if you inherit one copy from mom and one from dad because both your parents are carriers, you get the disease. Chandler is confident that new DNA technology can offer the test for all 400 for $125. You can spend more on a maternity dress.
But before the DNA test can be offered, it needs to be validated—that is, known carriers must have their DNA tested, and the screening must correctly identify them as carriers, while not identifying non-carriers as carriers. That is, no false negatives and no false positives—or as near to “no” as one can get, which Chandler believes is 99.9 percent accurate. To validate the test for autosomal recessive orphan diseases, he figures he needs 5 to 10 couples for each disease. If you want to be one of them—volunteering to spare other children these fatal diseases—you can contact Kristin Thomas Miskovsky at kmiskovsky@biophysicalcorp.com, or call her at 512.623.4923.