Better method for predicting genetic risk of type 1 diabetes in people with African ancestry

Posted on 24 January 2019

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Researchers in the US have devised a predictive test that can identify who is at higher risk of type 1 diabetes specifically in people of African ancestry.

The work involved analysing the genetic data of the largest number of people of African backgrounds with type 1 diabetes – 1,021 – ever studied.

Currently, genetic risk score tests are almost exclusively based on European data, which makes them less useful and suitable for people from different backgrounds.

This new test will help us spot better who with African ancestry is at greater risk of type 1 diabetes, and put them onto prevention trials or early treatment when appropriate.

The work was partly funded by JDRF.

Why did they do this research?

Researchers have been developing ways of predicting who is likely to develop type 1 diabetes based on certain genes.

Rates of type 1 diabetes are high in Europe, and so this research has largely been carried out using genetic data from people with European ancestry.

This means however that the ensuing prediction tests may not be as accurate or suitable for people from different backgrounds.

A team of researchers in the US therefore decided to develop a predictive genetic risk score test for people of African ancestry.

What did they do?

The team collected and analysed genetic information from 1,021 people with African backgrounds with type 1 diabetes. The researchers also studied 2,928 controls who didn’t have type 1.

The team used this genetic information to devise a genetic risk score for type 1 diabetes specifically for people with African ancestry.

The team then compared the new genetic risk score with European-based ones by analysing the group of people with African backgrounds and other, independent data sets, to  see which genetic risk score made more accurate predictions of type 1 risk.

What did they find?

There was an overlap of high-risk genes between people of European and African backgrounds.

People of African ancestry however also had certain high-risk sections of DNA that were specific to them.

The African-specific genetic risk score was much better at identifying people at risk of type 1 diabetes in people of African ancestry, than the European risk scores.

What does this mean for type 1?

Being able to predict who is likely to develop type 1 diabetes allows for more targeted screening of people to check for early signs of type 1 diabetes.

This can help to ensure that people receive appropriate care and treatment before they become very ill.

This new test will help to spot people of African ancestry at risk better than before, and so could lead to improved diagnosis and care for this group of people.

The researchers concluded in their paper:

“These results suggest that population-specific [genetic risk scores] can provide significantly improved prediction and opportunities for targeted interventions in individuals at risk for type 1 diabetes.”

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