Recently I saw a piece on NBC Nightly News about a pair of six-year-old boys, Dylan Siegel and Jonah Pournazarian, who’ve raised over $300,000 for to battle a rare disease that Jonah has called Glycogen Storage Disease (GSD 1b). It’s a beautiful story: best friends since preschool, Dylan wanted to help his friend by raising money to cure his disease, so he wrote a book called, “Chocolate Bar,” and that’s how they’ve raised such an impressive amount of money, with 100% going to research.
What caught my eye about the story, however, wasn’t just the fact that the kids are doing something wonderful and philanthropic – it was the cause itself. And while it inspired me to give to the foundation and encourage others to as well, it also has inspired me to blog about genetic testing.
GSD 1b is a rare genetic disease that occurs in one in a million children, and until very recently, it was always fatal. Luckily for Jonah, there have been great strides in treating the disease, including the discovery that a steady supply of glycogen in the form of a cornstarch solution, delivered through a feeding tube, can sustain him. Still, the regimen is grueling, and even a common cold can be a terrifying health hazard. And while the gene related to GSD 1b has been identified, there is no cure — yet.
We each inherit two sets of genes: one from our mother, and one from our father. There are many diseases that have been identified that are associated with mutations in our genes, including cystic fibrosis, sickle cell anemia, and Tay-Sachs, to name a few. Many of these diseases are inherited in an autosomal recessive fashion: this means a child will develop a genetic illness ONLY if they inherit two abnormal copies of the gene. But just because a parent is well, doesn’t mean that s/he doesn’t carry the mutated gene.
Since the human genome project, and the identification of the DNA sequence in humans, advances in genetic technology are moving at an exponential pace. When I was pregnant with my first child, Tay-Sachs testing was in its infancy. Now all pregnant women are encouraged to consider genetic testing. But what to test for and when?
For years, testing was done by sequencing the gene, and each test was run individually – a very expensive endeavor. For this reason, ethnic profiling was used to determine who should be screened by each test, as genetic diseases are often more prevalent in certain ethnic groups. Also, insurance companies only covered pregnancy; so genetic testing routinely happened AFTER conception. Of course this approach was inherently flawed, as if both of the parents screened positive for a recessive/mutated gene, then the only options available were to test the baby during pregnancy or at birth. If the baby was affected, the couple had two very difficult choices: either terminate the pregnancy or raise a child with a severe disease.
I believe preconception genetic testing and counseling should be the norm. If both parents carry the same mutated genes, then they can decide to take their chances and conceive and test the fetus OR they can choose to test embryos prior to conception. In Vitro Fertilization (IVF) can be performed and embryos screened for genetic diseases. The couple then can choose to transplant only non-affected or carrier embryos and avoid the transfer of a child destined to have this awful disease. While this may sound like selective eugenics, if couples are offered amniocentesis and termination, then eugenics is already being practiced. And isn’t it easier for a couple to practice selectivity prior to a pregnancy?
As for ethnic profiling to choose who gets screened and for which tests, again technology is paving the way for improved options. Years ago, when the only tests were long intensive screening of each gene, the cost somewhat precluded offering all tests to all women and led to the rise of ethnic profiling in genetic counseling. Today, newer chip array technology has changed all that. Now we can do preconception genetic testing for ALL couples for a fraction of the cost FOR MORE diseases than was ever offered. Today approximately 100 genes can be screened for less money than one cystic fibrosis screening test. Of course all of this brings up a host of ethical questions.
Should we screen everyone for VERY rare diseases? Is it necessary to make patients anxious about their genetic mutations if the diseases are not fatal? It is certainly a slippery slope of choosing genes for a child prior to conception or birth. And it is my personal opinion that ethnic profiling in genetic counseling is wrong. When cost is no longer a significant factor, I feel it makes sense to screen everyone for all serious diseases.
As a physician, I took an oath to do no harm. If one of my patients were in an ethnic group that typically didn’t need screening for a diseases, such as cystic fibrosis or Tay-Sachs and yet they delivered an affected child, I would not feel comfortable telling her that I could’ve known the risk in advance, but it wasn’t worth testing her. This is not a hypothetical situation: according to the Tay-Sachs Society, more babies born with Tay-Sachs disease are not of Jewish, French Canadian, or Cajun descent, which are the groups traditionally offered testing. Of course a couple always should have the right to refuse testing or decline to act on the test results, but as a gynecologist, I am obligated to inform all of my patients of the available tests.
There are no easy answers in this brave new world of genetic testing. Jonah inherited a rare disease, but his twin brother and older sister did not. For some, genetic counseling can help inform decisions prior to conception; for others, the emphasis should shift to working for cures for these rare diseases. As a doctor, I am committed to staying on the cutting edge of research so my patients can make informed decisions about what is best for their families.
For more about Jonah’s story and to make a donation to help fight GSD 1b, visit www.chocolatebarbook.com.