Amish gene protects their heart

Researchers investigating heart disease factors in an Amish community found some of them had a gene variant that seemed to keep down levels of triglycerides or blood fats, and may also be involved in keeping arteries clear of blockages since only those who had it were relatively free of arterial calcification.

Different people have different responses to fatty foods. Unused calories become triglycerides, which increase the risk of heart disease and stroke, and some people have much higher levels of these blood fats. Although diet is an obvious factor, some genes are also thought to play a major role. For example, when mice don't have the AP0C3 (short for Apolipoprotein C-III) gene they have low levels of triglycerides, regardless of what they eat. And coronary artery disease is thought to be related to this gene because it inhibits hydrolysis of triglycerides (their elimination).

800 healthy adult male and female members of the Old Order Amish in Lancaster County, Pennsylvania took part in a genome-wide association study where they had short term exposures to a range of environmental factors, such as eating a high salt diet, and then underwent a range of clinical exams.

This Amish community is quite cut off from the outside world and members tend to marry each other, creating an interesting population for geneticists because of the relatively higher proportions of people with the same gene variants compared to the world at large, making it easier to search for particular disease genes.

About 5 per cent of the Amish had one of their inherited AP0C3 genes switched off (they were heterozygous), which meant they had only half the AP0C3 expression of most other people.

They found that compared to non-carriers, the carriers of the switched off AP0C3 variant:

• Had lower levels of triglycerides (fasting and post-prandial), higher levels of HDL cholesterol (the so-called "good" cholesterol) and lower levels of LDL cholesterol (the so-called "bad" cholesterol), and


• Were less likely to have coronary artery calcification, an early sign of blocked arteries or atherosclerosis.

The researchers said these results suggested that "lifelong deficiency" of AP0C3 had a "cardioprotective effect". However, the Amish population is unique, so the mutation they found is probably not a mutation that you're going to find in other populations.



Adapted from Medical News Today website

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