Could rheumatoid arthritis give us clues for type 1 diabetes?

Posted on 20 September 2018

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Research into autoimmune conditions like rheumatoid arthritis can give us insights into type 1 diabetes, another autoimmune condition.

A recent study on rheumatoid arthritis in identical twins has identified similarities in the way DNA is packaged up in comparison with people living with type 1 diabetes.

Rheumatoid arthritis (RA) and type 1 diabetes are both autoimmune conditions that have a number of features in common.

This type of research helps us to understand why autoimmune conditions affect some people but not others, and potentially help us spot which environmental factors are linked with the development of these conditions.

This will inform the design of new treatments to prevent these conditions from ever developing in people.

Why did they do this research?

All autoimmune conditions studied so far have been shown to be associated with genetic factors. We know that environmental factors also play a role, although what exactly these environmental factors are remains largely unclear.  In this study, the researchers wanted to discover which environmental factors are linked to genetic factors by studying DNA methylation

What is DNA methylation?

When people are exposed  to environmental factors, such as infections, it can affect how DNA is packaged up and which genes are switched on or off. This process is known as DNA methylation, and it  leaves a specific ‘signature’ in your DNA. This signature is like an archive with a list of all environmental factors which we were exposed to throughout our lives.

Therefore finding common DNA methylation signatures indicating similar environmental factors across many different autoimmune conditions is very important as it can potentially pave the way to discover new treatments for people with different autoimmune conditions.

What did they do?

The researchers compared DNA methylation in sets of identical twins where one twin had RA and the other twin didn’t. Identical twins are very valuable for research as they have identical DNA, making it is easier to spot any differences between them.

Differences in their DNA methylation will correspond to differences in the environmental factors to which they’ve been exposed, which might indicate which environmental factors are linked with the development of RA.

This allowed the team to identify some specific immune system pathways that were affected in twins with RA.

The team then compared their results with earlier studies on type 1 diabetes and found a number of similarities in both autoimmune conditions.

What does this mean for type 1?

Common changes to immune system pathways were discovered between RA and type 1 diabetes, which could indicate where to target new treatments for both conditions. These findings can also help us to understand why cases of autoimmune conditions are on the rise in recent years.

Further work will help us to work out which environmental factors are responsible for these changes to immune system pathways, which will help us to avoid them.

What’s the next step?

The researchers propose to design further studies where they can experimentally test the observed DNA methylation changes associated with different autoimmune conditions and then pin down the culprit environmental factor.

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