Claiming Diagnostic Tests for Diabetes Genes Is Misleading

Armen Hareyan's picture

Predictive genetic testing for type 2 diabetes

Claims that the discovery of a gene could help prevent diabetes may raise unrealistic expectations, warn doctors in this week's BMJ.


Earlier this year, scientists discovered that a variant of the TCF7L2 gene was associated with type 2 diabetes. In subsequent media coverage, they claimed this could lead to a diagnostic test to identify people who carry the variant gene and that people who knew of their extra risk would then be motivated to avoid the lifestyle habits that lead to diabetes.

Undeniably this discovery is noteworthy, write Cecile Janssens and colleagues. Type 2 diabetes is a leading cause of illness and death in the developed world and is increasing in prevalence worldwide. The association is robust - the investigators replicated their finding in three large, independent study populations - and it offers potential new insight into the pathobiology of diabetes.

Yet the claim that this knowledge will lead to a diagnostic test and hence to disease prevention