Diabetic retinopathy and nephropathy are the most significant complications associated with diabetes, but two point mutations in a specific gene may protect a person from developing either of them, a new study reported.

Diabetic retinopathy, caused by damage to the blood vessels of the retina, results in vision problems that can range from mild to blindness. Diabetic nephropathy is a progressive kidney disease caused by damage to the capillaries in the kidneys and is a prime reason for dialysis in many developed countries.

Both of these complications involve damage of tiny blood vessels (capillaries) caused mainly by high blood sugar, although genetic factors also play a role. Results from experiments conducted on both human and animal cells suggest that the presence of vitamin B1 within the cell can avert the harm caused by high blood sugar.

The study, “Variation in SLC19A3 and Protection from Microvascular Damage in Type 1 Diabetes,” was published in the journal, Diabetes.

Professor Massimo Porta (University of Turin in Italy), Professor Per-Henrik Groop (head of the FinnDiane project at the University of Helsinki and Folkhälsan Research Centre) and colleagues investigated the influence of point genetic mutations on the genes encoding proteins responsible for transferring vitamin B1 into cells. Researchers hypothesized that such mutations have an impact in the individual capacity to transfer vitamin B1 into cells and therefore on an individual’s likelihood of developing diabetes-associated complications.

Researchers used a comprehensive type 1 diabetes patients’ data set gathered by Groop’s research team, which is the most extensive in the world and includes a characterization of patients based on their genetic profile and on the severity of their diabetes-associated clinical complications.

The results revealed that two of the studied point genetic mutations in a gene called SLC19A3 were linked with retinopathy and with the combination of retinopathy and nephropathy; consequently, carriers of the genetic variant were less susceptible to suffer from these diabetic complications. The results remained significant for this protecting effect even when researchers accounted for other diabetes risk factors. The analysis was repeated on patient data from North America, confirming that the two genetic variants protect their carriers from diabetic retinopathy and diabetic nephropathy.

“Based on these results, it seems that the SLC19A3 gene has a role in the development of diabetic nephropathy and diabetic retinopathy. The results also help explain why some patients with type 1 diabetes are more likely to develop complications than others,” Iiro Toppila, the researcher responsible for analyzing the data, said in a news release. “However, further research is needed into the biological effects of point mutations.”