A recent study of identical twins with HCM found significant variation in the expression of hypertrophic cardiomyopathy, even between twins carrying the same HCM-causing genetic mutation.
This paper concludes that epigenetics (things which influence expression of DNA like behavioral and environmental factors) greatly influence the expression of HCM genetic mutations.
The researchers studied 11 pairs of twins with HCM. 9 of the twin pairs had known HCM sarcomere mutations while 2 of the pairs had HCM of unknown cause. The siblings were followed for a time frame of between 5 to 14 years.
Researchers compared left ventricular wall thickness, left atrial size and left ventricular ejection fraction. Differences were found in the left ventricular wall thickness of all 11 pairs of twins, while left atrial size was similar in 3 of the 9 twin pairs who carried HCM mutations. Left ventricular ejection fraction was different in 4 of 7 twin pairs.
The researchers theorize that similarities in left atrial size may be due to impaired ventricular relaxation directly tied to sarcomere dysfunction. In contrast, environmental factors yield more influence over ventricular function.
HCM epigenetics is a field ripe for research. As HCM patients, we hope that it will yield actionable data in the near future.
A recent discovery by British researchers sheds light on how a type of common genetic mutation – a so called “common variant” – influences the expression of hypertrophic cardiomyopathy caused by mutation(s) in the cardiac sarcomere.
How do Common Variants Impact Sarcomere Mutations?
This research, funded by the British Heart Foundation and spearheaded by Dr. Hugh Watkins of the University of Oxford, explains why some individuals with a particular sarcomere mutation develop a severe case of HCM, while their family members with the same mutation may develop only mild HCM symptoms or show no signs of the disease at all. It also may explain why people who lack sarcomere mutations develop the disease.
The researchers compared the DNA of 2,780 people with HCM and 47,486 people without HCM and found that common variants acting in concert with rare sarcomere mutations determine whether a person will develop HCM.
Common Variant HCM Not Hereditable
In addition, the researchers found that HCM attributable to common variants alone is unlikely to be passed on to future generations. This is good news for the children of HCM patients caused by common variants.
Watch your Blood Pressure
Lastly, this paper found that high diastolic blood pressure was associated with the development of HCM caused by common variants. Hence, keeping blood pressure under control is something that patients can do to minimize their risk of developing HCM in the future.