Variations in the gene SLC19A3 protect against diabetic retinopathy
Differences in the way the body uses vitamin B1 affect the risk of complications from diabetes
The risk of severe diabetic retinopathy is lower in people with certain genetic variations linked to vitamin B1, according to new research. Variations in the gene SLC19A3 are also linked to a lower risk of severe retinopathy together with kidney disease.
Diabetic retinopathy is a major complication of diabetes. It can lead to blindness if left untreated. Over time, high blood sugar from diabetes damages blood vessels that supply the light-sensitive part of the eye (the retina).
What affects the risk?
Sight-threatening diabetic retinopathy is more common in people who’ve had diabetes longer or whose diabetes is poorly controlled. But not everyone with diabetes develops complications. This means there might be more to it than long-term high blood sugar or other risk factors such as high blood pressure and cholesterol can explain.
Previous research in cells and animals has shown that vitamin B1 (thiamine) can prevent damage from high blood sugar by controlling glucose (a type of sugar) inside cells. So researchers at the University of Helsinki and University of Turin suspected that a genetic change that affects how well thiamine can get into cells might be involved in diabetic retinopathy and kidney disease (nephropathy – another complication of diabetes).
The team tested 134 genetic variations in 2 of the genes (known as SLC1932 and SLC19A3) that make proteins to transport thiamine inside cells. Data came from the world’s largest group of patients with type 1 diabetes.
Results published in the journal Diabetes show that 2 variations in the gene SLC19A3 are linked to lower risk of severe retinopathy alone and also to lower risk of severe retinopathy combined with end-stage nephropathy. The results were confirmed in a repeat analysis including patients from North America.
“We know that some people with diabetes seem more likely than others to develop complications such as severe diabetic retinopathy,” said Dr Dolores M Conroy, Director of Research at Fight for Sight. “These results are interesting because they may help explain why. Being able to identify who is at most at risk of sight-loss means that we can start moving towards more personalised care.”Fulbright Fight for Sight Research Award winner Dr Christine Kirre is also working towards more personalised treatments for people with diabetic retinopathy. Read more about her upcoming research project at the University of Wisconsin.