Eight years and a pandemic later, the foundation has set its sights on a smaller, more manageable 10-year goal: better understanding how the human cell works, Dr. Priscilla Chan—wife of Meta founder, chairman, and CEO Mark Zuckerberg—told attendees of Fortune’s Impact Initiative gathering on Wednesday in Atlanta.

Such knowledge is necessary for achieving the organization’s greater goal, Chan, a pediatrician, told Fortune’s Ellie Austin, who hosted the discussion. 

“We’re in a place in science where we can look at mutations, and we can look at the end state of what happens in disease,” Chan said. “The middle is, largely, a complete mystery.”

Cells are difficult to study for a few reasons, according to Chan. For one, there are “trillions of them, of all different types.” Secondly, “they’re really, really small.” What’s more, they’re dynamic, continually adapting and responding to their environment.

“Our goal is to really understand what cells are doing in healthy and disease states, so we can help patients and families understand what’s happening in their bodies and how to actually address it,” she said.

An impactful intersection of health equity and rare disease

While the CZI contributes billions to medical research and other causes each year, in comparison to the likes of the U.S. National Institutes of Health, it’s a “teeny-tiny” player, Chan said. Because of the organization’s relatively small scale, “we have to be really careful and strategic about where we think we can bring differentiated value.”

“Can we be a unique contributor in this space, based on the resources and capabilities we have?” she asked rhetorically.

The initiative has found it can make an outsize impact at the intersection of healthy equity and rare disease. While rare diseases alone are rare, collectively, they’re common. Approximately one in 10 individuals globally will be diagnosed with a rare disease in their lifetime, according to the National Organization for Rare Disorders—making uncommon diseases a major yet underappreciated public health issue.

The diagnostic odyssey—or the journey to a diagnosis for a rare disease patient—takes, on average, four to nine years, and can include medical gaslighting, complete denial by doctors, and wrong diagnoses. Some patients will never receive the answers they’re so desperately seeking.

For rare disease patients, the journey to a diagnosis is “a place of large inequity,” Chan said. Not all patients—especially those in second- and third-world countries—“have access to established medical centers.” Even among those who do, many “aren’t well connected to the right centers” and “spend a lot of their time just bouncing one place to another, without getting an answer.”

The CZI is “working very closely with rare disease groups to make sure we learn from their experiences and understand how the science we’re supporting can be applied quickly and equitably” to rare disease patients, so they can be diagnosed more rapidly, Chan said—with the goal of improving outcomes and quality of life for such patients.

Added Chan: “One of the first and most clarifying steps in their health journey is to get the treatment they need.”