Gene variant can delay diabetes diagnosis in black and Asian men

A gene variant that can cause inaccurate type 2 diabetes blood test results is more prevalent in black and South Asian men, and can delay diagnosis.

A genetic condition called G6PD deficiency, which affects red blood cells, can lead to inaccurate results on the HbA1c blood test which is routinely used to diagnose type 2 diabetes (see BioNews 1236). Researchers from the University of Exeter and Queen Mary University of London examined the impact of this condition on type 2 diabetes diagnosis and complications at the population level. They found that one in seven black men and one in 63 South Asian men carry this gene variant compared to fewer than one in 10,000 white men, and that carriers were diagnosed with type 2 diabetes four years later, on average, than non-carriers.

'Our findings highlight the urgent need for changes to testing practices to tackle health inequalities. Doctors and health policy makers need to be aware that the HbA1c test may not be accurate for people with G6PD deficiency and routine G6PD screening could help identify those at risk,' said Professor Inês Barroso, from the University of Exeter, lead author of the paper published in Diabetes Care.

The team examined health and genetic data from over 500,000 individuals in the UK Biobank population cohort and the Genes & Health community-based study of British Bangladeshis and Pakistanis. They also found that people carrying the variant were at a higher risk of developing diabetes-related complications such as eye and nerve damage compared to non-carriers with type 2 diabetes.

Additionally, the findings showed that under one percent of black men and less than three percent of Asian men carrying this gene variant had a diagnosis of G6PD deficiency on their health record. The World Health Organisation's recommendations that countries should routinely screen for this gene variant are not widely implemented.

'Addressing the impact of G6PD deficiency on diabetes testing is an important step towards reducing inequalities and making sure that everyone, regardless of background, benefits equally from medical advances,' said Dr Esther Mukuka, director of research inclusion at the National Institute for Health and Care Research, which supported the research.

The researchers acknowledged that further studies in a more diverse pool of participants worldwide are needed to help strengthen these findings. However, they noted that the study is an important step forward in highlighting and addressing clear health inequalities in type 2 diabetes diagnosis.