Genetic variants could explain type 1 diabetes diagnoses in later life

Having different genetic markers could explain why people develop type 1 diabetes at different ages, including later in life, according to new research.
Certain gene groups are known to be associated with the development of type 1 diabetes, and UK researchers have now shown that the risk of developing the condition after 30 years is different to the risk of developing type 1 diabetes in childhood.
The study was conducted by scientists at the University of Exeter, who explored the role of the DR3 and DR4 gene alleles which are observed in children with an increased risk of type 1 diabetes.
They studied 120,000 individuals from the UK Biobank from birth to the age of 60, all of whom were in the highest genetic risk group for type 1 diabetes.
Analysis found that the highest risk genotypes made up 6.4 per cent of the UK population and contributed to 61 per cent of all type 1 diabetes cases. There were marked differences in both the likelihood of developing type 1 diabetes and the average age of diagnosis.
This difference depended on the genotypes: those with DR3/DR4 genes were 4.2 per cent more likely to develop type 1 diabetes during a person’s lifetime, while this figure was 3.5 per cent for DR4/DR4 genes and 1.2 per cent for DR3/DR3.
Significantly, 71 per cent of diagnoses associated with the DR4/DR4 genotype were in individuals over the age of 30.
The authors said: “Whilst all three major genotypes greatly increase risk of T1D throughout life, population analysis has shown for the first time that DR4/DR4 specifically predisposes to T1D over 30 years of age and carriers of this genotype have the highest risk for development of late-onset T1D.
“This is clear evidence that type 1 diabetes after 30 years is not just a delayed version of type 1 diabetes before 30. Further work is needed to understand these differences.”
The study findings were reported at the annual meeting of the European Association for the Study of Diabetes (EASD) in Lisbo, Portugal.