Sammy Basso is one of around 400 young people in the world with progeria.
Just 400 or so people in the world live with progeria: The mutation that causes it usually arises de novo, or "of new," meaning that it is not inherited but happens spontaneously during gestation. The challenge, as with all rare diseases, is that few cases means few treatments.
"When we first started, there was absolutely nothing out there," says Leslie Gordon, a physician-researcher who co-founded the Progeria Research Foundation in 1999 after her own son, also named Sam, was diagnosed with the disease. "We knew we had to jumpstart the entire field, so we collected money through road races and special events and writing grants and all sorts of donors… I think the first year we raised $75,000, most of it from one donor."
"We have not only the possibility but the responsibility to make the world a better world, and also to make a body a better body."
By 2003, the foundation had collaborated with Francis Collins, a geneticist who is now director of the National Institutes of Health, to work out the genetic basis for progeria—that single mutation Sammy has. The discovery led to interest in lonafarnib, a drug that was already being used in cancer patients but could potentially operate downstream of the mutation, preventing the buildup of the defective progerin in the body. "We funded cellular studies to look at a lonafarnib in cells, mouse studies to look at lonafarnib in mouse models of progeria… and then we initiated the clinical trials," Gordon says.
Sammy Basso's family had gotten involved with the Progeria Research Foundation through their international patient registry, which maintains relationships with families in 49 countries. "We started to hear about lonafarnib in 2006 from Leslie Gordon," says Sammy's father, Amerigo Basso, with his son translating. "She told us about the lonafarnib. And we were very happy because for the first time we understood that there was something that could help our son and our lives." Amerigo used the Italian word speranza, which means hope.
Still, Sammy wasn't sure if lonafarnib was right for him. "Since when I was very young I thought that everything happens for a reason. So, in my mind, if God made me with progeria, there was a reason, and to try to heal from progeria was something wrong," he says. Gradually, his parents and doctors, and Leslie Gordon, convinced him otherwise. Sammy began to believe that God was also the force behind doctors, science, and research. "And so we have not only the possibility but the responsibility to make the world a better world, and also to make a body a better body," he says.
Sammy Basso and his parents.
Courtesy of Basso
Sammy began taking lonafarnib, with the Progeria Research Foundation intermittently flying him, and other international trial participants, to Boston for tests. He was immediately beset by some of the drug's more unpleasant side effects: Stomach problems, nausea, and vomiting. "The first period was absolutely the worst period of my life," he says.
At first, doctors prescribed other medicines for the side effects, but to Sammy it had as much effect as drinking water. He visited doctor after doctor, with some calling him weekly or even daily to ask how he was doing. Eventually the specialists decided that he should lower his dose, balancing his pain with the benefit of the drug. Sammy can't actually feel any positive effect of the lonafarnib, but his health measurements have improved relative to people with progeria who don't take it.
While they never completely disappeared, Sammy's side effects decreased to the point that he could live. Inspired by the research that led to lonafarnib, he went to university to study molecular biology. For his thesis work, he travelled to Spain to perform experiments on cells and on mice with progeria, learning how to use the gene-editing technique CRISPR-Cas9 to cut out the mutated bit of DNA. "I was so excited to participate in this study," Sammy says. He felt like his work could make a difference.
In 2018, the Progeria Research Foundation was hosting one of their biennial workshops when Francis Collins, the researcher who had located the mutation behind progeria 15 years earlier, got in touch with Leslie Gordon. "Francis called me and said, Hey, I just saw a talk by David Liu from the Broad [Institute]. And it was pretty amazing. He has been looking at progeria and has very early, but very exciting data… Do you have any spaces, any slots you could make in your program for late breaking news?"
Gordon found a spot, and David Liu came to talk about what was going on in his lab, which was an even more advanced treatment that led to mice with the progeria mutation living into their senior mouse years—substantially closer to a normal lifespan. Liu's lab had built on the idea of CRISPR-Cas9 to create a more elegant genetic process called base editing: Instead of chopping out mutated DNA, a scientist could chemically convert an incorrect DNA letter to the correct one, like the search and replace function in word processing software. Mice who had their Lamin-A mutations corrected this way lived more than twice as long as untreated animals.
Sammy was in the audience at Dr. Liu's talk. "When I heard about this base editing as a younger scientist, I thought that I was living in the future," he says. "When my parents had my diagnosis of progeria, the science knew very little information about DNA. And now we are talking about healing the DNA… It is incredible."
Lonafarnib (also called Zokinvy) was approved by the US Food and Drug Administration this past November. Sammy, now 25, still takes it, and still manages his side effects. With luck, the gift of a few extra years will act as a bridge until he can try Liu's revolutionary new gene treatment, which has not yet begun testing in humans. While Leslie Gordon warns that she's always wrong about things like this, she hopes to see the new base editing techniques in clinical trials in the next year or two. Sammy won't need to be convinced to try it this time; his thinking on fate has evolved since his first encounter with lonafarnib.
"I would be very happy to try it," he says. "I know that for a non-scientist it can be difficult to understand. Some people think that we are the DNA. We are not. The DNA is a part of us, and to correct it is to do what we are already doing—just better." In short, a gene therapy, while it may seem like science fiction, is no different from a pill. For Sammy, both are a new way to think about fate: No longer something that simply happens to him.
Alida de Flamingh and her team are collecting elephant dung. It holds a trove of information about animal health, diet and genetic diversity.
Approximately 27 percent of mammals and 28 percent of all assessed species are close to dying out. The IUCN Red List of threatened species, simply called the Red List, is the world’s most comprehensive record of animals’ risk of extinction status. The more information scientists gather, the better their chances of reducing those risks. In Africa, populations of vertebrates declined 69 percent between 1970 and 2022, according to the World Wildlife Fund (WWF).
“We put on sterile gloves and use a sterile swab to collect wet mucus and materials from the outside of the dung ball,” says Alida de Flamingh, a postdoctoral researcher at the University of Illinois Urbana-Champaign.
“When people talk about species, they often talk about ecosystems, but they often overlook genetic diversity,” says Christina Hvilsom, senior geneticist at the Copenhagen Zoo. “It’s easy to count (individuals) to assess whether the population size is increasing or decreasing, but diversity isn’t something we can see with our bare eyes. Yet, it’s actually the foundation for the species and populations.” DNA analysis can provide this critical information.
Assessing elephants’ health
“Africa’s elephant populations are facing unprecedented threats,” says de Flamingh, the postdoc, who has studied them since 2009. Challenges include ivory poaching, habitat destruction and smaller, more fragmented habitats that result in smaller mating pools with less genetic diversity. Additionally, de Flamingh studies the microbial communities living on and in elephants – their microbiomes – looking for parasites or dangerous microbes.
Approximately 415,000 elephants inhabit Africa today, but de Flamingh says the number would be four times higher without these challenges. The IUCN Red List reports African savannah elephants are endangered and African forest elephants are critically endangered. Elephants support ecosystem biodiversity by clearing paths that help other species travel. Their very footprints create small puddles that can host smaller organisms such as tadpoles. Elephants are often described as ecosystems’ engineers, so if they disappear, the rest of the ecosystem will suffer too.
There’s a process to collecting elephant feces. “We put on sterile gloves (which we change for each sample) and use a sterile swab to collect wet mucus and materials from the outside of the dung ball,” says de Flamingh. They rub a sample about the size of a U.S. quarter onto a paper card embedded with DNA preservation technology. Each card is air dried and stored in a packet of desiccant to prevent mold growth. This way, samples can be stored at room temperature indefinitely without the DNA degrading.
Earlier methods required collecting dung in bags, which needed either refrigeration or the addition of preservatives, or the riskier alternative of tranquilizing the animals before approaching them to draw blood samples. The ability to collect and sequence the DNA made things much easier and safer.
“Our research provides a way to assess elephant health without having to physically interact with elephants,” de Flamingh emphasizes. “We also keep track of the GPS coordinates of each sample so that we can create a map of the sampling locations,” she adds. That helps researchers correlate elephants’ health with geographic areas and their conditions.
Although de Flamingh works with elephants in the wild, the contributions of zoos in the United States and collaborations in South Africa (notably the late Professor Rudi van Aarde and the Conservation Ecology Research Unit at the University of Pretoria) were key in studying this method to ensure it worked, she points out.
Protecting chimpanzees
Genetic work with chimpanzees began about a decade ago. Hvilsom and her group at the Copenhagen Zoo analyzed DNA from nearly 1,000 fecal samples collected between 2003 and 2018 by a team of international researchers. The goal was to assess the status of the West African subspecies, which is critically endangered after rapid population declines. Of the four subspecies of chimpanzees, the West African subspecies is considered the most at-risk.
In total, the WWF estimates the numbers of chimpanzees inhabiting Africa’s forests and savannah woodlands at between 173,000 and 300,000. Poaching, disease and human-caused changes to their lands are their major risks.
By analyzing genetics obtained from fecal samples, Hvilsom estimated the chimpanzees’ population, ascertained their family relationships and mapped their migration routes.
“One of the threats is mining near the Nimba Mountains in Guinea,” a stronghold for the West African subspecies, Hvilsom says. The Nimba Mountains are a UNESCO World Heritage Site, but they are rich in iron ore, which is used to make the steel that is vital to the Asian construction boom. As she and colleagues wrote in a recent paper, “Many extractive industries are currently developing projects in chimpanzee habitat.”
Analyzing DNA allows researchers to identify individual chimpanzees more accurately than simply observing them, she says. Normally, field researchers would install cameras and manually inspect each picture to determine how many chimpanzees were in an area. But, Hvilsom says, “That’s very tricky. Chimpanzees move a lot and are fast, so it’s difficult to get clear pictures. Often, they find and destroy the cameras. Also, they live in large areas, so you need a lot of cameras.”
By analyzing genetics obtained from fecal samples, Hvilsom estimated the chimpanzees’ population, ascertained their family relationships and mapped their migration routes based upon DNA comparisons with other chimpanzee groups. The mining companies and builders are using this information to locate future roads where they won’t disrupt migration – a more effective solution than trying to build artificial corridors for wildlife.
“The current route cuts off communities of chimpanzees,” Hvilsom elaborates. That effectively prevents young adult chimps from joining other groups when the time comes, eventually reducing the currently-high levels of genetic diversity.
“The mining company helped pay for the genetics work,” Hvilsom says, “as part of its obligation to assess and monitor biodiversity and the effect of the mining in the area.”
Of 50 toucan subspecies, 11 are threatened or near-threatened with extinction because of deforestation and poaching.
Identifying toucan families
Feces aren't the only substance researchers draw DNA samples from. Jeffrey Coleman, a Ph.D. candidate at the University of Texas at Austin relies on blood tests for studying the genetic diversity of toucans---birds species native to Central America and nearby regions. They live in the jungles, where they hop among branches, snip fruit from trees, toss it in the air and catch it with their large beaks. “Toucans are beautiful, charismatic birds that are really important to the ecosystem,” says Coleman.
Of their 50 subspecies, 11 are threatened or near-threatened with extinction because of deforestation and poaching. “When people see these aesthetically pleasing birds, they’re motivated to care about conservation practices,” he points out.
Coleman works with the Dallas World Aquarium and its partner zoos to analyze DNA from blood draws, using it to identify which toucans are related and how closely. His goal is to use science to improve the genetic diversity among toucan offspring.
Specifically, he’s looking at sections of the genome of captive birds in which the nucleotides repeat multiple times, such as AGATAGATAGAT. Called microsatellites, these consecutively-repeating sections can be passed from parents to children, helping scientists identify parent-child and sibling-sibling relationships. “That allows you to make strategic decisions about how to pair (captive) individuals for mating...to avoid inbreeding,” Coleman says.
Jeffrey Coleman is studying the microsatellites inside the toucan genomes.
Courtesy Jeffrey Coleman
The alternative is to use a type of analysis that looks for a single DNA building block – a nucleotide – that differs in a given sequence. Called single nucleotide polymorphisms (SNPs, pronounced “snips”), they are very common and very accurate. Coleman says they are better than microsatellites for some uses. But scientists have already developed a large body of microsatellite data from multiple species, so microsatellites can shed more insights on relations.
Regardless of whether conservation programs use SNPs or microsatellites to guide captive breeding efforts, the goal is to help them build genetically diverse populations that eventually may supplement endangered populations in the wild. “The hope is that the ecosystem will be stable enough and that the populations (once reintroduced into the wild) will be able to survive and thrive,” says Coleman. History knows some good examples of captive breeding success.
The California condor, which had a total population of 27 in 1987, when the last wild birds were captured, is one of them. A captive breeding program boosted their numbers to 561 by the end of 2022. Of those, 347 of those are in the wild, according to the National Park Service.
Conservationists hope that their work on animals’ genetic diversity will help preserve and restore endangered species in captivity and the wild. DNA analysis is crucial to both types of efforts. The ability to apply genome sequencing to wildlife conservation brings a new level of accuracy that helps protect species and gives fresh insights that observation alone can’t provide.
“A lot of species are threatened,” Coleman says. “I hope this research will be a resource people can use to get more information on longer-term genealogies and different populations.”