Under Diagnosed but Treatable: The hATTR Amyloidosis Story
Question: What’s a rare disease you’ve probably never heard of that’s not really all that rare?
Answer: On the offhand chance you answered amyloidosis, you’d be right. But amyloidosis, a group of conditions caused by the buildup of misfolded proteins called amyloid fibrils in the body, is an unlikely guess because it’s a condition that doesn’t get much press.
When amyloids are deposited around the cells in an organ—kidney, lung, brain, heart—that protein disrupts the function of that organ, Matthew Maurer, M.D., professor of cardiology at Columbia University, and a geriatric cardiologist at College of Physicians and Surgeons, Clinical Cardiovascular Research Laboratory for the Elderly at New York Presbyterian Hospital, told the audience gathered at the Third Black Health Matters Health Summit at Riverside Church in Harlem earlier this month.
TTR is the most common form in the heart. The genetic form, known as hereditary amyloidosis or hATTR, affects mostly people of African descent. It’s considered a rare disease, with research suggesting it affects about 50,000 people in this country.
That number, however, is too low, according to Maurer, who places the number of folks in the United States with hATTR to be closer to 150,000. (The National Institutes of Health define any disease with fewer than 200,000 sufferers as rare.) “We hear more about cystic fibrosis, Tay-Sachs and sickle cell than we do about amyloidosis, even though it’s much more prevalent,” he said. “If we went to the hospital and went to newborns, we’d find TTR in 1 in every 25 to 30 babies. Sickle cell is found in 1 in 500 to 600 African American babies. Tay-Sachs, typically found in people of Jewish descent, affects 1 in 2000. [With these numbers] this is not a rare condition.”
So why have so few of us heard of hATTR?
Along the west coast of African, the genetic mutation that causes hATTR was found in the Ivory Coast, Sierra Leone and Guinea. “This is informative because we know this is where most African Americans came from,” Maurer said. “Even if you have the mutated gene, it doesn’t mean you’ll develop the disease. Even if you have the mutated gene, it develops much later in life. How many survive to age 60 or 65, when this disease shows up?”
In one study from London Afro-Caribbean patients with heart failure were screened for the genetic mutation that causes hATTR. Ten percent of those patients carried the mutation (we know that about 20 percent of people who have the mutation will develop the disease), leading researchers to extrapolate that hATTR is the fourth leading cause of heart disease.
“Most cardiologists believe it’s 40 on the list,” Maurer said. “If doctors don’t even know about it, you have a hard time treating it.”
Harder still is getting out of the hurry up and wait western mindset. “The American strategy: Wait for things to get really, really bad, and then try to fix them. We need to identify this problem earlier and prevent it from happening,” Maurer said.
To change the current approach to TTR, which is a devastating disease that makes the heart muscle thick, leathery and less efficient and which doesn’t show up until after age 50 in men and after 60 or 70 in women, we need screening and early diagnosis. We need to change our approach from one that’s reactive to one that’s proactive.
Identifying people earlier and giving them effective treatments has become easier recently with new detection methods and recently FDA-approved therapies:
- The old way to diagnose amyloidosis was with an invasive heart biopsy. Now there’s a heart scan that takes 6 minutes and can be done in any doctor’s office.
- One therapy is an IV drug that directs medication to the liver and tells it to stop making this one protein. “This is gene silencing,” Maurer said. “With it we slow down this particular disease.”
- A second therapy is a pill that stabilizes the mutated protein, keeping it from falling apart and lodging in the heart.
- A third medication, tafamdis, which in trials reduced the chance of dying by 64 percent in people with early stage disease, could receive FDA approval by summer.
“Drugs work better when given earlier,” Maurer said. That’s why physicians encourage folks with the mutation to get other family members tested so they don’t continue to pass on the disease.
Finally, the five-year Scan-MP study is in the process of recruiting elderly black and hispanic patients with heart failure to see how many may have hATTR. Using highly sensitive heart imaging and blood tests, investigators will also explore differences in genetics and sex as they relate to heart failure disease progression in hATTR.
“We have a lot of wrongs to right in this world,” Maurer said. “The study is trying to change the paradigms. We’re trying to diagnose a disease that has been under diagnosed and is treatable.”
For more information on hATTR Amyloidosis see the Black Health Matters Health Conditions Hub.
For more information about the our Black Health Matters Summit 2019.