The rapid increase in our understanding of human genetics over the past few decades has the potential to revolutionize healthcare. Surveys in 2019 and 2022 by the personal genomics company 23andMe and its research partners found that two-thirds of physicians think genetic testing can be leveraged to improve outcomes for patients. Moreover, 92 percent of physicians say that genetics is essential to understanding the individual health profile of a patient. Perhaps even more importantly, 75 percent of patients surveyed say they would be more likely to follow the advice of a doctor if it was tailored according to their genetic profile.
“The cost of sequencing base pairs of DNA has decayed even faster than the cost of semiconductors, unlocking enormous potential,” says Patrick Chung of Xfund, who was 23andMe’s first venture investor.
It’s clear that the reality of personalized healthcare is closer than ever before. This is a remarkable fact considering that sequencing of the human genome was completed for the first time only 20 years ago.
Remaining Challenges on the Road to Personalized Medicine
The sequencing of the human genome came with the promise of a new kind of healthcare. Both genomics (the study of genomes) and genetics (the study of individual genes) can unlock new ways of preventing, diagnosing, and treating diseases and allow for more personalized healthcare delivery. With information about a patient’s genetic makeup, physicians can understand the patient’s individual risk for disease, diagnose conditions earlier, and determine the treatments most likely to be effective for that patient. Meanwhile, researchers are gaining a better sense of the impact of individual genes on health and of the interplay between genes and environment in disease pathology.
Despite its benefits, genetic testing is still not a routine part of healthcare, despite the availability of direct-to-consumer genetic tests. For example, a physician might recommend genetic testing only if a patient has a family history of a specific genetic disorder. Similarly, sequencing of the entire genome for individual patients is now feasible, but rare.
However, some patterns are already emerging linking chronic diseases like diabetes to specific genetic patterns. The next step involves translating these patterns into clinical guidelines for physicians. For some conditions, clear guidelines already exist. For example, the BRCA1 and BRCA2 gene variants carry a much higher risk of breast and ovarian cancer, among other neoplasms.
There is still the issue of identifying who would benefit from genetic screening for these conditions. One study found that 80 percent of people with one of these variants were not aware of it. The guidelines, which influence insurance reimbursement, depend on people knowing their ethnic background or family history. About half of people with one of these variants do not qualify for testing based on these guidelines.
Genetics, Disease, and Treatment Response
Genetic testing can give people significant insight into their risk of developing certain conditions. For example, a common variant in the TTR gene among people of West African descent increases the risk of developing heart failure. This variant is implicated in a significant portion of heart failure cases among people over the age of 60. The problem is that the majority of people who have the variant never know about it—a fact with two implications. The first is that we cannot develop targeted therapies without identifying patients to include in studies. The second is that people who might benefit from these therapies never know that they are candidates. More widespread availability of testing could resolve both issues and save lives in the process.
It’s important to note that a person’s genetic makeup influences their health beyond their risk of developing a particular disease. Genetics influence how a person’s body responds to life-saving medications like warfarin, a blood thinner, and clopidogrel, an antiplatelet drug. People with certain genetic patterns do not respond to these medications and thus remain at risk of stroke, pulmonary embolism, and more. Genetic patterns also influence responses to statins, a class of medications that lower cholesterol, and selective serotonin reuptake inhibitors, a type of antidepressant. Although genetic testing might change prescribing decisions, it is not routinely done beforehand.
Technologies Enabling a Shift toward Personalized Medicine
Xfund was an early supporter of the personal genomics company 23andMe, which is dedicated to helping people access, understand, and benefit from their genetic data—and in the process, make healthcare more personal. The company pioneered the field of direct-to-consumer genetic testing in the late 2000s with its product which allows people to submit a saliva sample for DNA sequencing. The data output is both robust and reliable. People can learn an incredible amount about their ancestry, trace people around the world they might be related to, and learn about their personal health risks.
23andMe helped transform a process that took a long time and cost a small fortune into a fast and affordable at-home test, without sacrificing accuracy. Since the company’s inception, tens of millions of people have chosen to have their DNA sequenced.
“We have amassed an incredible data asset,” said Chung. “It is one of the world’s largest known databases of matched genotypes and phenotypes.”
Xfund is also an investor in Nebula Genomics, which offers whole genome sequencing based on methods pioneered by Harvard Medical School professor George Church. A decade ago, sequencing a human genome cost around $10,000; Nebula’s service does it for $299. Data privacy is a major focus for the company as well. Nebula is the first to offer anonymous genetic testing, meaning that customers can get their genome sequenced without submitting any identifying information about themselves, including credit card details (payment is via cryptocurrency). The company is also developing secure systems to allow patients to share their genomic data with researchers without compromising their privacy.
We do not have widespread access to personalized healthcare just yet, and this is not a problem that tech companies or even the private sector can solve alone. However, the technologies and products developed by 23andMe, Nebula Genomics, and other leaders in personal genomics and genetics bring us closer every year.
“Our children will live in an incredible world of personalized medicine that we are only now beginning to glimpse,” added Patrick Chung of Xfund.