Causes of Polygenic disorders

Influence of the environment

Very few health conditions are only caused by genes - most are caused by the combination of genes and environmental factors. Environmental factors include lifestyle factors, such as diet and exercise.

Around a dozen or so genes determine most human characteristics, such as height and the likelihood of developing common conditions.

Genes can have many variants, and studies of the whole genome - the whole set of genes - in large numbers of people are showing these variants may increase or decrease a person's chance of having certain conditions.

Each variant may only increase or decrease the chance of a condition very slightly, but this can add up across several genes.

In most people, the gene variants balance out to give an average risk for most conditions. But in some cases the risk is significantly above or below the average.

It's thought it may be possible to reduce the risk by changing environmental and lifestyle factors.

For example, coronary heart disease - when the heart's blood supply is blocked or interrupted - can run in families, but a poor diet, smoking and a lack of exercise can also increase your risk of developing the condition.

Research suggests that in the future, individuals will be able to find out what conditions they're most likely to develop.

It may then be possible to significantly reduce the chances of developing these conditions by making appropriate lifestyle and environmental changes.

Source: NHS Choices UK1

   •   •   •

Back to: « Polygenic disorders

   •   •   •


  1. Source: NHS Choices UK: conditions/ genetics/ inheritance/ 

   •   •   •

Note: This site is for informational purposes only and is not medical advice. See your doctor or other qualified medical professional for all your medical needs.