Reported in Nature Communications, the cardioprotective variant was found in an isolated Greek population, who are known to live long and healthy lives despite having a diet rich in animal fat.
In Mylopotamos, northern Crete the population are unusual as their diet should cause health complications, yet they have good health and live to an old age.
Investigating further, scientists made a genetic portrait of the population by sequencing the entire genome of 250 individuals to get an in-depth view. This was the first time Mylopotamos villagers had their whole genome sequenced. The team then used the results to give a more detailed view of approximately 3,200 people for whom previous genetic information was known.
Scientists discovered a new genetic variant that was not previously known to have cardioprotective qualities. The variant, rs145556679*, was associated with lower levels of both ‘bad’ natural fats – triglycerides – and ‘bad’ cholesterol – very low density lipoprotein cholesterol (VLDL). These factors lower the risk of cardiovascular disease.
The cardioprotective variant may be almost unique to the Mylopotamos population. The genome sequencing results of a few thousand Europeans has only revealed one copy of this variant in a single individual in Tuscany, Italy. A separate variant in the same gene has also been found to be associated with lower levels of triglycerides in the Amish founder population in the United States.
Commenting on the study, Lorraine South joint first author from the Wellcome Trust Sanger Institute: “By studying isolated populations, we are able to identify those genetic variants that are at a higher frequency compared to cosmopolitan populations and this in turn increases our power to detect if these variants are disease causing. With isolated populations, we can get a unique view into rare genetic variants that play important roles in complex human diseases.”
The team also studied an isolated population from mountainous villages in the Pomak region of northern Greece. Scientists studied the genetics of 1700 people in the population, and discovered four separate genetic variants that affect diastolic blood pressure, fasting glucose levels, white blood cell count and haemoglobin levels.
“We have discovered a medically relevant genetic variant for traits related to cardiovascular disease, the most common cause of death worldwide” said lead author, Professor Eleftheria Zeggini from the Wellcome Trust Sanger Institute.
