Genetic Connection Between Heart Disease And Human Reproduction Revealed

How did the genes that led to heart disease, one of the biggest killers on the globe, persist for so long? According to new research, the same genes that wreak havoc on our heart serve a more beneficial purpose: They help us have babies.

The study, published online in PLOS Genetics, found that the same genes responsible for coronary artery disease (CAD), also play a major role in successful human reproduction; the genes are involved in "...functions in male and female fertility being expressed in the testes, ovaries, and endometrium..." Futurityreported. The team believes that this may explain why evolution allowed otherwise deadly genes to remain in the human genome for so long.

“Evolution, it seems, is involved in a trade-off where CAD only begins to appear at around 40-50 years of age when the potential beneficial effects of these genes on reproduction have already occurred,” explained lead author Sean Byars from the School of BioSciences at the University of Melbourne, Futurity reported.

For the study, the team looked at 56 genetic regions for CAD in 12 worldwide populations originating in Africa, Europe, and East Asia. They specifically looked to see if there have been any recent changes to genes associated with heart disease, and were surprised to find that these genes were more or less untouched for many generations. This prompted them to further investigate why these genes had been preserved for so long. It’s here where they realized that the genes associated with CAD were also vital for human reproduction. The team explained that this does not mean that people who reproduce and have many children are more likely to develop heart disease, but rather that heart disease is a by-product of humans' ability to reproduce successfully.

“This represents direct evidence that genes that have been under selection are also beneficial for reproduction and, yet, are associated with occurrence of a common disease later in life,” explained lead study author Michael Inouye, Futurity reported.

According to the National Institute of Health, coronary heart disease occurs when plaque builds up in the arteries meant to supply oxygen to the heart. As the plaque builds up over the course of many years, it can narrow the arteries, restricting blood flow or causing a blood clot that can also stop blood flow. When this occurs, the heart is deprived of blood and the individual may experience a heart attack.

As science further develops to allow us the ability to edit genes, this study offers a warning that sometimes the effects of genes can be complex and editing them out can have unforeseen consequences.

Source: Byars SG, Huang QQ< Gray LA, et al. Genetic loci associated with coronary artery disease harbor evidence of selection and antagonistic pleiotropy. PLOS Genetics. 2017