When Ozzie, a 30-year Navy veteran, tells people he has cardiomyopathy of transthyretin-mediated amyloidosis (ATTR-CM), also known as ATTR cardiac amyloidosis, he usually gets a blank look.

“If you tell people you have prostate cancer, people know immediately,” he says. “With this, there’s no understanding of what it is.”

Ten years ago, he didn’t know much about it either. At 55, Ozzie was still running and swimming regularly. During a comprehensive annual physical exam, a cardiologist added an ultrasound of his heart. It showed potential signs of amyloid buildup.

Mike, a Kansas City business owner, took a much longer road to the same diagnosis. For more than a decade, he brought one symptom after another to his doctors, and no one connected them.

ATTR-CM starts when a protein called transthyretin (TTR) misfolds and forms amyloid deposits in the heart. Over time, these amyloid deposits build up, causing the heart muscle to thicken, so it becomes harder for the heart to pump blood throughout the body. Mike has hereditary ATTR-CM (hATTR-CM), caused by an inherited variant in the TTR gene. Ozzie has wild-type ATTR-CM (wtATTR-CM), which occurs without an inherited variant and is generally associated with aging.

The clues they didn’t know were connected

In his early 50s, Mike noticed numbness along the side of his leg, and a neurologist suggested a pinched nerve. Then a biceps tendon ruptured during an ordinary workout, which his orthopedist called age-related wear and tear. Then came carpal tunnel syndrome.

“No one was putting the pieces together,” he says.

Ozzie had carpal tunnel syndrome in both wrists and torn biceps tendons in both arms. When his swim times started slipping, he figured he was just getting older.

Neither man knew these problems can be linked to ATTR-CM. Carpal tunnel syndrome, particularly in both wrists, and certain tendon or ligament problems can precede cardiac symptoms of ATTR-CM by years. Other signs can include shortness of breath, fatigue, swelling in the legs, numbness or tingling in the hands or feet, and an irregular heartbeat.* Because these clues often emerge over time and bring patients to different specialists, the connection can be difficult to see.

Eventually, Mike’s symptoms became impossible to ignore. Lifting a heavy box left him winded. He began passing out. But sitting in the cardiologist’s office, he never thought to mention symptoms from years earlier.
“As a patient, what would that have to do with the heart?” he says.

The diagnosis was not the end of the story

Initially diagnosed with atrial fibrillation, Mike was scheduled for a procedure to reset his heart rhythm, but a nurse noticed something concerning during monitoring, and further testing ultimately led him to an ATTR-CM diagnosis.

Ozzie calls himself a “relentless researcher.” After his diagnosis, he read medical journals late into the night and attended conferences. When his cardiologist raised the possibility of a heart transplant, Ozzie came back with an article by an amyloidosis specialist. His cardiologist knew the author and called him right then, with Ozzie in the room. That conversation led to a referral to specialized care and additional discussions on how Ozzie manages his ATTR-CM.

“If you’re aggressive and you’re relentless, sometimes you run into good fortune,” he says.

Mike, too, sought out physicians experienced in treating ATTR-CM and learned as much as he could about the disease.

Turning experience into advocacy

Mike eventually found something else he had been missing: a community.

Through amyloidosis conferences and patient organizations, he met people who understood the uncertainty that could come before, and even after, a diagnosis.

He also kept hearing conversations about disparities in diagnosis of ATTR-CM. One TTR variant, known as V122I, is found disproportionately among Black Americans. Yet many people who carry a hereditary TTR variant may be unaware of it.

At one conference, after listening to another discussion about the need to do more, Mike walked to the microphone.

“What’s the ‘more?’” he asked. “And why isn’t it being done?”

By the next morning, he had decided to start Amyloidosis Army, a nonprofit that raises awareness about amyloidosis among healthcare professionals and Black communities. It has since held more than 60 awareness programs, where the group talks about symptoms and hereditary risk, helps people find local specialists and, in some cities, offers testing on site.

Staying relentless, while advancing the science

Alongside advocacy, research is critical to addressing unmet needs for people living with ATTR-CM. For Ozzie, being relentless also meant traveling from Chicago to New York to take part in two clinical trials, requiring time away from family and a willingness to live with uncertainty.

“I trade some time, energy and some difficulty – in exchange, I get peace of mind knowing I’m doing everything I can,” he says. Today, he still swims and coaches his son’s hockey team.

Mike feels the same way. “Without people in clinical trials, you don’t have research,” he says. “If we don’t have research, we’re not going to make any progress.”

Progress depends both on scientific discovery and listening to people with a disease. By sharing their experiences, Mike and Ozzie are helping raise awareness of ATTR-CM and what it can mean to live with the condition. Alongside its work to research and develop medicines, Alnylam Pharmaceuticals, a leading biotechnology company, is committed to bringing stories like theirs forward and supporting the efforts of patient advocacy organizations to educate people about ATTR-CM.

What they want others to know

Though Mike and Ozzie’s paths were different, their stories underscore the same lesson: awareness can change what people know to ask.

For someone experiencing unexplained symptoms, that may mean looking back at the full picture, including carpal tunnel syndrome, fatigue or shortness of breath, and asking a healthcare professional whether those symptoms could be connected. For someone newly diagnosed, it may mean seeking out physicians experienced in ATTR-CM and finding a community that understands the disease firsthand.

Resources like Amyloidosis Support Groups connect patients and caregivers with others in the community who understand what they’re facing. The Amyloidosis Research Consortium offers My Amyloidosis Pathfinder to help people find specialists and clinical trials. And ATTR Revealed, a disease-education website from Alnylam, shares information about the signs and symptoms of ATTR-CM, along with tools to support conversations with healthcare professionals.

For Alnylam, World Amyloidosis Day is an opportunity not only to advance understanding of the science, but to elevate the experiences of people living with ATTR-CM and help more people recognize the signs that can be easy to overlook.

The message from Mike and Ozzie is simple: Don’t dismiss the pieces that don’t seem to fit. Learn the signs. Share your full health history. Ask questions. And if something still does not make sense, keep looking for answers.

*This is not a complete list of symptoms. Symptoms may vary.

AMV-USA-01936 9/2026