When doctors couldn’t stop her daughter’s seizures, this mom earned a PhD and found a treatment herself.
Twenty-eight years ago, Tracy Dixon-Salazaar woke to the sound of her daughter, two-year-old Savannah, in the midst of a medical emergency.
“I entered [Savannah’s room] to see her tiny little body jerking about violently in her bed,” Tracy said in an interview. “I thought she was choking.” When she and her husband frantically called 911, the paramedic told them it was likely that Savannah had had a seizure—a term neither Tracy nor her husband had ever heard before.
Over the next several years, Savannah’s seizures continued and worsened. By age five Savannah was having seizures dozens of times each day, and her parents noticed significant developmental delays. Savannah was unable to use the restroom and functioned more like a toddler than a five-year-old.
Doctors were mystified: Tracy and her husband had no family history of seizures, and there was no event—such as an injury or infection—that could have caused them. Doctors were also confused as to why Savannah’s seizures were happening so frequently despite trying different seizure medications.
Doctors eventually diagnosed Savannah with Lennox-Gaustaut Syndrome, or LGS, an epilepsy disorder with no cure and a poor prognosis. People with LGS are often resistant to several kinds of anti-seizure medications, and often suffer from developmental delays and behavioral problems. People with LGS also have a higher chance of injury as well as a higher chance of sudden unexpected death (SUDEP) due to the frequent seizures. In about 70 percent of cases, LGS has an identifiable cause such as a brain injury or genetic syndrome. In about 30 percent of cases, however, the cause is unknown.
Watching her daughter struggle through repeated seizures was devastating to Tracy and the rest of the family.
“This disease, it comes into your life. It’s uninvited. It’s unannounced and it takes over every aspect of your daily life,” said Tracy in an interview with Today.com. “Plus it’s attacking the thing that is most precious to you—your kid.”
Desperate to find some answers, Tracy began combing the medical literature for information about epilepsy and LGS. She enrolled in college courses to better understand the papers she was reading.
“Ironically, I thought I needed to go to college to take English classes to understand these papers—but soon learned it wasn’t English classes I needed, It was science,” Tracy said. When she took her first college science course, Tracy says, she “fell in love with the subject.”
Tracy was now a caregiver to Savannah, who continued to have hundreds of seizures a month, as well as a full-time student, studying late into the night and while her kids were at school, using classwork as “an outlet for the pain.”
“I couldn’t help my daughter,” Tracy said. “Studying was something I could do.”
Twelve years later, Tracy had earned a PhD in neurobiology.
After her post-doctoral training, Tracy started working at a lab that explored the genetics of epilepsy. Savannah’s doctors hadn’t found a genetic cause for her seizures, so Tracy decided to sequence her genome again to check for other abnormalities—and what she found was life-changing.
Tracy discovered that Savannah had a calcium channel mutation, meaning that too much calcium was passing through Savannah’s neural pathways, leading to seizures. The information made sense to Tracy: Anti-seizure medications often leech calcium from a person’s bones. When doctors had prescribed Savannah calcium supplements in the past to counteract these effects, her seizures had gotten worse every time she took the medication. Tracy took her discovery to Savannah’s doctor, who agreed to prescribe her a calcium blocker.
The change in Savannah was almost immediate.
Within two weeks, Savannah’s seizures had decreased by 95 percent. Once on a daily seven-drug regimen, she was soon weaned to just four, and then three. Amazingly, Tracy started to notice changes in Savannah’s personality and development, too.
“She just exploded in her personality and her talking and her walking and her potty training and oh my gosh she is just so sassy,” Tracy said in an interview.
Since starting the calcium blocker eleven years ago, Savannah has continued to make enormous strides. Though still unable to read or write, Savannah enjoys puzzles and social media. She’s “obsessed” with boys, says Tracy. And while Tracy suspects she’ll never be able to live independently, she and her daughter can now share more “normal” moments—something she never anticipated at the start of Savannah’s journey with LGS. While preparing for an event, Savannah helped Tracy get ready.
“We picked out a dress and it was the first time in our lives that we did something normal as a mother and a daughter,” she said. “It was pretty cool.”
Your Beloved Pet Is Old. Should You Clone It?
Melvin was a special dog. A mixture of Catahoula and Doberman with black and tan markings, he was the office greeter, barking hellos to everyone who visited the Dupont Veterinary Clinic in Lafayette, Louisiana, which is owned by his human companions, Dr. Phillip Dupont and his wife, Paula. The couple say he's the best dog they ever owned.
When Melvin passed away, having two identical replicas helped ease the couple's grief.
He seemed to have an uncanny knack for understanding what they were saying, he could find lost car keys in tall grasses and the Duponts trusted him so much they felt comfortable having him babysit their grandson unattended in the backyard.
So when the 75-pound canine turned 9 and began to show signs of age, the Duponts sent off some of his skin cells to a lab in South Korea, the Sooam Biotech Research Foundation, to have him cloned. The Duponts toured the South Korean facilities and were satisfied that the animals were being treated well. While the first cloned puppy died from distemper, the second attempt produced two healthy animals—which the couple named Ken and Henry. When Melvin did pass away nearly two years later, in 2014, having two identical replicas helped ease the couple's grief. Even though it cost about $70,000 to clone Melvin, it was well worth it. "Melvin gave us a lot of pleasure," says Paula Dupont, "and this was less than the price of a new Land Cruiser."
As the technology improves, costs will tumble, making pet cloning more affordable for the mainstream.
The news has been filled recently with stories of celebrities such as Barbra Streisand or billionaire Barry Diller and his fashion icon wife, Diane von Furstenberg, spending big bucks to preserve their beloved pets—a practice New York magazine called "a laughable, extravagant waste of money." But cloning Fido isn't just for the ultra-wealthy anymore. Texas-based ViaGen now offers a domestic cloning service that will replicate Lassie for $50,000 and Garfield's kittens for a mere $25,000. While the exact number of cloned pets isn't known, the South Korean company says it has cloned about 800 pets while ViaGen has cloned about 100 cats and dogs. And as the technology improves, costs will tumble, making it more affordable for the mainstream, says Ron Gillespie, who heads PerPETuate, a Massachusetts-based outfit that collects and cryo preserves pet DNA, and works closely with ViaGen.
Even if the animals are genetic twins, biologists say, there are no guarantees their personalities will match, too.
While replicating Fido is becoming more feasible, should you? Animal rights organizations like The Humane Society and PETA are sharply critical of the practice, which is largely unregulated, and think it's outrageous to spend $50,000 or more to preserve Fluffy's genetic makeup when millions of cats and dogs are languishing in shelters and millions more are euthanized every year. And even if the animals are genetic twins, biologists say, there are no guarantees their personalities will match, too. Like humans, dogs' personalities are influenced by their environment and there are always variations in how the genes are expressed--although the Duponts say that Ken and Henry seem more like Melvin every day. "Their personalities are identical," says Paula.
Clones Ken and Henry, with Dr. Dupont and 10-year-old Melvin. Though all three dogs are genetic twins, their markings differ because the environment can influence how genes are expressed.
Still, the loss of a beloved pet can be incredibly painful, and in some cases, cloning can help deal with deep psychological wounds. When Monni Must's daughter died suddenly at age 28, the Michigan-based photographer adopted her child's black Lab, Billy Bean. As the dog got older and frailer, Must realized she couldn't handle losing her last link to her daughter—so she ponied up $50,000 to have the animal cloned. "I knew that I was falling apart," Must told Agence France-Presse. "The thought of Billy dying was just more than I could handle."
But these heated disputes miss what bioethicists believe is the real ethical dilemma—the fate of the female animals that provide the eggs and gestate the cloned puppies. "This issue tends to get framed as 'it's their personal choice, it's their money and they can do what they want with it,'" says Jessica Pierce, a bioethicist and author of Run, Spot, Run: The Ethics of Keeping Pets. "But this whole enterprise has all this collateral damage and behind-the-scenes impacts that people ignore. No one is talking about the dogs who are sacrificing themselves for this indulgence, and are suffering and being tormented just to have your clone."
"Even in the best-case scenarios, the cloned pet may go through several rounds of failed reproductive attempts—failed pregnancies, still births, and deformities."
Animal cloning, of course, is not new. Dolly, the sheep, made her debut in 1996 as the first cloned mammal. In 2005, Korea's Sooam Biotech cloned the first dog, and cloning horses and cows has become almost routine. Typically, the cloning process for dogs is fairly uncomplicated. It entails the use of a group of female dogs whose hormones are artificially manipulated with drugs to promote them to produce eggs. The eggs are then surgically harvested from donor dogs' ovaries. The immature eggs are stripped of their genetic information and then the pet's DNA is fused with the egg. When the embryo begins to develop, it is then transplanted to the womb of a surrogate dog.
However, cloning can have a high failure rate. When South Korea's Sooam Biotech lab cloned the first dog in 2005, there were 1000 failures—which means that number of eggs were fertilized and began to gestate, but at some point their development failed. And this figure doesn't include the number of dogs born with deformities serious enough that they are incompatible with life and need to be euthanized. "Even in the best-case scenarios, the cloned pet may go through several rounds of failed reproductive attempts—failed pregnancies, still births, and deformities," says Insoo Hyun, a bioethicist at Case Western Reserve University in Cleveland. "You can't do just one egg and one transfer. That won't happen. There is no guarantee that the very first time you will have a healthy animal. They're not miracle workers and you can't fight biology."
"You just have to let your pet go. It's all part of the experience."
But Ron Gillespie, who's been in the animal breeding business for decades, thinks these fears are overblown and that cloning is similar to the selective breeding that goes on all the time with cattle and even with champion racehorses. "We're really the victim of a lot of misinformation and misunderstanding," he says. "Right now, on average, we're dealing with three dogs: two that supply eggs and one to carry the embryo to term."
Still, this debate skirts the hard realities: dogs and cats simply have shorter lifespans than humans, and ethicists and animal rights activists believe there are better ways to deal with that grief. "You just have to let your pet go," says Hyun. "It's all part of the experience."
Genome Reading and Editing Tools for All
In 2006, the cover of Scientific American was "Know Your DNA" and the inside story was "Genomes for All." Today, we are closer to that goal than ever. Making it affordable for everyone to understand and change their DNA will fundamentally alter how we manage diseases, how we conduct clinical research, and even how we select a mate.
A frequent line of questions on the topic of making genome reading affordable is: Do we need to read the whole genome in order to accurately predict disease risk?
Since 2006, we have driven the cost of reading a human genome down from $3 billion to $600. To aid interpretation and research to produce new diagnostics and therapeutics, my research team at Harvard initiated the Personal Genome Project and later, Openhumans.org. This has demonstrated international informed consent for human genomes, and diverse environmental and trait data can be distributed freely. This is done with no strings attached in a manner analogous to Wikipedia. Cell lines from that project are similarly freely available for experiments on synthetic biology, gene therapy and human developmental biology. DNA from those cells have been chosen by the US National Institute of Standards and Technology and the Food and Drug Administration to be the key federal standards for the human genome.
A frequent line of questions on the topic of making genome reading affordable is: Do we need to read the whole genome in order to accurately predict disease risk? Can we just do most commonly varying parts of the genome, which constitute only a tiny fraction of a percent? Or just the most important parts encoding the proteins or 'exome,' which constitute about one percent of the genome? The commonly varying parts of the genome are poor predictors of serious genetic diseases and the exomes don't detect DNA rearrangements which often wipe out gene function when they occur in non-coding regions within genes. Since the cost of the exome is not one percent of the whole genome cost, but nearly identical ($600), missing an impactful category of mutants is really not worth it. So the answer is yes, we should read the whole genome to glean comprehensively meaningful information.
In parallel to the reading revolution, we have dropped the price of DNA synthesis by a similar million-fold and made genome editing tools close to free.
WRITING
In parallel to the reading revolution, we have dropped the price of DNA synthesis by a similar million-fold and made genome editing tools like CRISPR, TALE and MAGE close to free by distributing them through the non-profit Addgene.org. Gene therapies are already curing blindness in children and cancer in adults, and hopefully soon infectious diseases and hemoglobin diseases like sickle cell anemia. Nevertheless, gene therapies are (so far) the most expensive class of drugs in history (about $1 million dollars per dose).
This is in large part because the costs of proving safety and efficacy in a randomized clinical trial are high and that cost is spread out only over the people that benefit (aka the denominator). Striking growth is evident in such expensive hyper-personalized therapies ever since the "Orphan Drug Act of 1983." For the most common disease, aging (which kills 90 percent of people in wealthy regions of the world), the denominator is maximal and the cost of the drugs should be low as genetic interventions to combat aging become available in the next ten years. But what can we do about rarer diseases with cheap access to genome reading and editing tools? Try to prevent them in the first place.
A huge fraction of these births is preventable if unaffected carriers of such diseases do not mate.
ARITHMETIC
While the cost of reading has plummeted, the value of knowing your genome is higher than ever. About 5 percent of births result in extreme medical trauma over a person's lifetime due to rare genetic diseases. Even without gene therapy, these cost the family and society more than a million dollars in drugs, diagnostics and instruments, extra general care, loss of income for the affected individual and other family members, plus pain and anxiety of the "medical odyssey" often via dozens of mystified physicians. A huge fraction of these births is preventable if unaffected carriers of such diseases do not mate.
The non-profit genetic screening organization, Dor Yeshorim (established in 1983), has shown that this is feasible by testing for Tay–Sachs disease, Familial dysautonomia, Cystic fibrosis, Canavan disease, Glycogen storage disease (type 1), Fanconi anemia (type C), Bloom syndrome, Niemann–Pick disease, Mucolipidosis type IV. This is often done at the pre-marital, matchmaking phase, which can reduce the frequency of natural or induced abortions. Such matchmaking can be done in such a way that no one knows the carrier status of any individual in the system. In addition to those nine tests, many additional diseases can be picked up by whole genome sequencing. No person can know in advance that they are exempt from these risks.
Furthermore, concerns about rare "false positives" is far less at the stage of matchmaking than at the stage of prenatal testing, since the latter could involve termination of a healthy fetus, while the former just means that you restrict your dating to 90 percent of the population. In order to scale this up from 13 million Ashkenazim and Sephardim to billions in diverse cultures, we will likely see new computer security, encryption, blockchain and matchmaking tools.
Once the diseases are eradicated from our population, the interventions can be said to impact not only the current population, but all subsequent generations.
THE FUTURE
As reading and writing become exponentially more affordable and reliable, we can tackle equitable distribution, but there remain issues of education and security. Society, broadly (insurers, health care providers, governments) should be able to see a roughly 12-fold return on their investment of $1800 per person ($600 each for raw data, interpretation and incentivizing the participant) by saving $1 million per diseased child per 20 families. Everyone will have free access to their genome information and software to guide their choices in precision medicines, mates and participation in biomedical research studies.
In terms of writing and editing, if delivery efficiency and accuracy keep improving, then pill or aerosol formulations of gene therapies -- even non-prescription, veterinary or home-made versions -- are not inconceivable. Preventions tends to be more affordable and more humane than cures. If gene therapies provide prevention of diseases of aging, cancer and cognitive decline, they might be considered "enhancement," but not necessarily more remarkable than past preventative strategies, like vaccines against HPV-cancer, smallpox and polio. Whether we're overcoming an internal genetic flaw or an external infectious disease, the purpose is the same: to minimize human suffering. Once the diseases are eradicated from our population, the interventions can be said to impact not only the current population, but all subsequent generations. This reminds us that we need to listen carefully, educate each other and proactively imagine and deflect likely, and even unlikely, unintended consequences, including stigmatization of the last few unprotected individuals.