Research led by Dr Miriam Samuel and colleagues in the Genes & Health study has shown that a gene variant almost exclusively found in people of South Asian heritage affects the accuracy of the HbA1c test commonly used to diagnose type 2 diabetes.
In England, it is estimated that there are over 420,000 people from a South Asian background living with diabetes, and over 230,000 have a diagnosis of prediabetes. Type 2 diabetes is a common condition that causes the level of sugar (glucose) in the blood to become too high. It increases the risk of getting serious problems with your eyes, feet, heart and nerves. It's caused by problems with a chemical in the body (hormone) called insulin. It's often linked to being overweight or inactive, or having a family history of type 2 diabetes.
In this study, funded by Diabetes UK, Dr Samuel and her colleagues used genetic and health data from the Genes & Health study of over 60,000 individuals of Bangladeshi or Pakistani ethnicity living in England, and the UK Biobank of 500,000 people of varied ethnicity living in the UK. The study has recruited from many of the GP Practices across North London as well as East London Foundation Trust.
A genetic variant was identified that is found in 7.6% of people of South Asian heritage but which is extremely rare in other ethnicities. When given the HbA1c test – which measures average blood sugar levels over the preceding two to three months - the gene caused a falsely low result.
Dr Miriam Samuel, NIHR Academic Clinical Fellow in the Primary Care Unit, Wolfson Institute of Population Health, said:
“Many genetic variants linked to red blood cell conditions are ultra-rare amongst the Northern Europeans who have historically dominated genetic studies. We demonstrate one such variant that is carried by 7.6% of South Asians which could affect the accuracy of HbA1c and cause delays in diabetes diagnosis.”
More information on the results of the study is available from Queen Mary's University London: Standard diabetes test may be inaccurate for 10,000s of South Asian people in UK
Image: Towfiqu Barbhuiya