As President Donald Trump directs cuts of tens of thousands of federal government employees, among those laid off at America’s health agencies are workers at a National Institutes of Health department focused on dementia research, including its incoming leader, three people familiar with the terminations told ABC News.

The firings at the Center for Alzheimer’s and Related Dementias (CARD) affected roughly a tenth of the nearly 100 employees at the center, but in interviews with ABC News, workers there described a carefully woven web of collaboration that they say could be threatened by the layoffs of just a handful of employees, warning that it could jeopardize progress in answering key questions about dementia.

Most shocking to CARD workers was the termination of lead researcher Kendall Van Keuren-Jensen, who was announced internally as the organization’s next acting director and was expected to bring significant advancements to the research field.

“It’s just jaw-dropping,” an upper-level CARD employee told ABC News of Van Keuren-Jensen’s firing.

ABC News reached out to Van Keuren-Jensen, who declined to comment.

The layoffs at CARD were first reported by the New Republic.

Neurologists say the downsizing at CARD could be a blow to the scientific quest for new Alzheimer’s treatments. NIH scientists at CARD work with external scientists to turn early scientific discoveries into treatments and medicines.

The center also had significant bipartisan support. It was named after Sen. Roy Blunt, a Missouri Republican who’s been a champion for dementia research funding.

Nearly 7 million people in the United States are living with Alzheimer’s disease, according to the Alzheimer’s Association. There is no cure, and current treatments only help relieve symptoms or slow down disease progression.

One laid-off CARD worker told ABC News that a termination letter, received on Feb. 15 from an NIH human resources official, cited the worker’s performance, even though the worker told ABC News that their managers had assured them their performance was not an issue.

Another CARD employee dismissed the idea that the layoffs were related to performance.

“[One colleague] recently published a first-author paper in a high impact journal and they were terminated for poor performance, and I said, are you kidding me?” they told ABC News.

The outgoing director, Andrew Singleton, told colleagues in an email that the layoffs would “have a profound impact on the work we do to understand and treat disease,” according to one CARD employee.

Singleton did not respond to a request for comment from ABC News.

A spokesperson from the Department of Health and Human Services did not respond to requests for comment.

Karoline Leavitt, the White House press secretary, said about the layoffs across federal agencies, “There should be no secret about the fact that this administration is committed to cutting waste, fraud and abuse. The president campaigned on that process campaigned on that promise. Americans elected him on that promise, and he’s actually delivering on it. And this is something that Democrats promised they would do for decades. President Trump is just the first president to get it done.”

Newly confirmed Health and Human Services Secretary Robert F. Kennedy Jr. advocated vast shakeups at the department, specifically laying out plans on the campaign trail to cut hundreds from the NIH, which he said should shift its focus away from infectious diseases toward chronic diseases.

“We need to act fast, and we want to have those people in place on Jan. 20 so that on Jan. 21, 600 people are going to walk into offices at NIH and 600 people are going to leave,” Kennedy said in November, speaking at the Genius Network Annual Event in Scottsdale, Arizona.

The firings at the Alzheimer’s research center comes amid a flurry of other changes to the government’s health agencies, including around 700 terminations at the Centers for Disease Control and Prevention and at least 90 more at the Food and Drug Administration of people who worked on nutrition, food safety and regulating infant formula, according to multiple officials at the agencies. There have also been cuts to other parts of HHS, including the Administration for Strategic Preparedness and Response.

Nearly all the staffers manning vaccines.gov, the website that helps people find vaccines in their area, were let go as well, an official who oversees the site said.

One senior Trump administration official told Fox News Digital the HHS “departures” were estimated to be 6,000 people, while other outlets have estimated 3,600 were cut. When asked by ABC News about the number, HHS wouldn’t confirm the details.

Additionally, a media campaign encouraging people to get their flu shots was removed from CDC’s website.