Question: Does your lifestyle affect whether you’re going to suffer from a genetic illness or not? Why?

Helena Fisk answered on 10 Jun 2020:

Hi Javier, great question!

So there are differing types of ‘genetic illness’. Some will be evident at birth such as Down’s syndrome in which an extra chromosome occurs which in most cases is not inherited, lifestyle choices are not known to be a cause of this however there is a link between how likely you are to give birth to a baby with this condition with increasing age of the mother (so ageing seems to be involved). Other diseases and the risk of developing disease can be inherited from our parents DNA. Some inherited diseases may not occur until puberty and the development and severity of some diseases with be affected by our lifestyle choices.

I’m going to use diabetes as an example of a disease in which your risk of developing it can be inherited and also be affected through lifestyle choices. You can inherit the risk of developing type 1 diabetes by inheriting certain gene variants from your parents. A cluster of genes are involved in your immune system and how your body recognises and responds to your own cells. In type 1 diabetes, inheriting certain variants of these genes can result in your body attacking the cells that produce insulin. If you can’t produce insulin, you can’t effectively remove glucose from your blood which is a main feature of diabetes. This type of diabetes can develop very quickly in children and young adults but the cause for us developing this mainly is in the genes we inherited.
However, this isn’t the case with type 2 diabetes. Type-2 diabetes is often seen to develop in later life and particularly with weight gain and obesity. Here our lifestyle choices (diet and exercise etc.) can greatly impact our risk of developing this disease in addition to our genes. Our lifestyle choices have an impact on the expression of our genes and something called methylation which is whether the transcription of a gene is turned on or off (if transcription of a gene is on, then the protein corresponding to that gene is made – this requires translation too). DNA methylation has been linked to developing cancer, atherosclerosis and other diseases. Smoking, consumption of alcohol, our diet and exercise have been seen to alter DNA methylation. The interaction of our lifestyle and our DNA/genes is called epigenetics.

Obesity results in major changes to the expression of our genes. Many of these genes are involved in processes in our body that if these were to stop acting in the ‘normal’ way, could result in developing diseases such as diabetes and cancer. Certain nutrients in our diet have also been seen to influence the transcription and expression of genes too.

Therefore there is definitely interaction between our risk of suffering from diseases that occur from changes in our genes and our lifestyle choices, but this will not be the case for many inherited genetic diseases.

I hope that helps!