Black and Latinx Americans have higher rates of heart disease and failure than do white Americans – and scientists have now discovered a gene variant that may help explain the baffling disparity.
Researchers at Mount Sinai and Penn Medicine discovered that a variant of a gene called TTR, which causes toxic proteins to accumulate on the heart and other organs, is far more common among black and Latinx people.
And people of these descents with the gene are at a twofold greater risk of heart failure.
Their study further suggested that the less common but often earlier appearing heart problems associated with the gene are likely under-diagnosed in these populations, adding weight to the argument for genetic screening.
A map from the new study shows that where more people reported African or Latinx heritage, the disease-causing gene variant was more common (highest percentage shown in red)
Nearly half (49 percent) of black women develop heart disease, compared to just 32 percent of white women.
Similar differences persist for men. An estimated 44 percent of black men develop heart disease, compared to just 37 percent of white men.
Interestingly, Latinx people have similar or lower rates of death from heart disease, but tend to have far more risk factors for cardiovascular problems, placing them in a treacherous gray area.
Heart disease is driven by both genetic factors as well as elements of lifestyle, like smoking, obesity, physical inactivity and poor diet.
Previous research has also noted that fewer black and Latinx Americans are aware of their risks for heart disease – a disparity that likely echoes poorer access to health care among this population.
While awareness and subsequent lifestyle changes present an opportunity for people to cut their risks, the genetic component of heart disease is nothing to be dismissed.
Earlier this year, Mount Sinai researchers and collaborators in Germany and Sweden did a large-scale analysis that suggested more than 30 percent of risk factors for heart disease are actually genetically derived.
It’s a far greater proportion than previously thought.
On the heels of that study, Mount Sinai and Penn researchers homed in on the genetics of these particularly at-risk groups.
The variant V1221 of the TTR gene is known to be more common among people with African ancestry.
TTR V1221 is associated with the buildup of toxic protein waste plaques, called amyloids, on the organs. These proteins disrupt the normal functioning of the heart, nerves or kidneys.
It can cause a condition thought to strike three to four percent of African Americans, called, heredity-transthyretin amyloid cardiomyopathy (hATTR-CM).
The disease can strike as early as 20, or as late as 80 and is often missed, for an average of four years.
And it can lead to heart failure.
In a sample of nearly 9,700 African Americans and Latinx Americans, people who carried the V1221 gene variant were twice as likely to develop heart failure as were those who did not carry the gene.
Just in the past year, the Food and Drug Administration (FDA) approved the first therapy to counteract the gene and treat hATTR-CM.
Up to this point, doctors haven’t recommended screening African and Latinx Americans for the gene, in part because only supportive care was available for hATTR-CM, rather than treatment.
But now that there is a drug available for the condition, the researchers are pushing for screening, anew.
‘Given recent advances in treatment for hATTR-CM, it is imperative to identify patients at risk for the disease and intervene before noticeable symptoms of the disease appear,’ said study author Dr Ron Do of Mount Sinai.
His co-author, Dr Girish Nadkarni, also of Mount Sinai, added: ‘These findings suggest that although the TTR genetic variant is known to cause hereditary TTR amyloidosis cardiomyopathy and heart failure, there is significant under-recognition and under-diagnosis of this disease, particularly in individuals of African and/or Latino ancestry.
‘Of the observed cases, only 11 percent of individuals with the TTR genetic variant were diagnosed appropriately. It’s imperative that genetic screening of TTR genetic variants be considered for early diagnosis of the disease and its treatment.’