The risk of developing a genetic disease drops off as we age © Getty Images

The risk of developing genetic diseases drops off as we age

The finding may enable scientists to predict a person’s future risk of disease by analysing their genome.

It’s widely known that as we age our immune systems become weaker and slower to respond to infection, leaving us at a greater risk of becoming ill. But when it comes to developing genetic diseases the risk of us becoming ill actually wanes with age, a study carried out at the University of Oxford has found.

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We each inherit half of our genes from our father and half from our mother. Our genes play a huge role in our appearance and development – from our hair colour to our height – but also influence our risk of developing all manner of diseases such as cancer and heart disease.

By using genomic data taken from 500,000 people and stored in the UK Biobank, the team at Oxford were able to look for the existence of age windows in which we are more likely to develop 24 common diseases linked to our genetics.

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They found that while different diseases show different risk patterns over the course of a person’s life, the genetic risk of developing many diseases, such as high blood pressure, skin cancer and under-active thyroids, peaks in early life and then drops off as we age.

“Our work shows that the way in which genetics affects your risk of getting a disease change throughout life,” said study lead Prof Gil McVean. “For many diseases, genetic factors are most important in determining whether you will get a disease early in life, while – as you age – other factors come to dominate risk.”

Currently, the reasons as to exactly why this is the case are unknown. There may be unknown processes at work, such interactions between a person’s genes and their environment that lead to them developing a disease, the researchers say.

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By further studying this relationship, the researchers hope to develop a deeper understanding of how age impacts a person’s risk of developing a disease due to their genes. This may help scientists to make more accurate predictions about whether an individual will ultimately become ill with a given condition, they say.

Reader Q&A: Are talents genetic or learnt?

Asked by: Luke Azzopardi, Malta

Both. Some people are born with greater potential, but without hard work and practising their talent will come to nothing. Music is a good example, with some evidence of genetic differences. For example, a study of 500 twins found that 80 per cent of tone deafness is inherited. Another found genes associated with serotonin release, which were related to musical creativity.

Chess is another good example: an analysis of 14 studies of top chess players and musicians concluded that only about 30 per cent of the variation between performers could be accounted for by their hours of practice. In contrast, a study of British musicians found that top performers had practised a lot more, but learned no faster than less skilled players.

A popular theory is that it takes 10,000 hours of practice to become an expert at something, and there is probably a degree of truth in this. But if your genes give you an aptitude for and enjoyment of chess, maths, music or football, you are surely more likely to put in those long hours.

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