Study probes genetic underpinning of diabetic retinopathy

Different genetic polymorphisms seem to be associated with different phenotypes of non-proliferative diabetic retinopathy (NPDR), according to a study presented by Jose Cunha-Vaz MD at the 14th  EURETINA Congress.

“It is known that diabetes causes neurodegenerative changes, and in the retina the microvascular response to the degenerative changes is different in different patients and is apparently genetically determined. Our study showed that different phenotypes of progression of NDPDR have different risks for progression to clinically significant macular oedema (CSME),” he said. 

Dr Cunha-Vaz noted that there are different risks for vision loss in different patients with similar metabolic control and duration of disease in vision-threatening proliferative DR and diabetic macular oedema. “Not all patients develop macular oedema, and not all patients develop neovascularization. It followsthen that there is a need to identify causes from natural history studies,” said Dr Cunha-Vaz.

Dr Cunha-Vaz’s prospective study of 348 patients with NPDR and two years follow-up set out to examine the association of different candidate genes with different phenotypes of NPDR and risk for development of CSME.Patients were classified in groups of three different phenotypes of DR progression based on non- invasive methods: colour fundus photography (CFP) to assess microaneurysm turnover (MAT) using the RetmarkerDR and optical coherence tomography (OCT) to measure retinal thickness (RT). The development of CSME was also addressed. Eleven genes were selected from a list of candidate genes and their single nucleotide polymorphisms (SNPs) were filtered through bioinformatics tools.Cluster analysis showed that phenotypes B and C present a much higher risk for CSME development when compared to subjects in phenotype A, said Dr Cunha-Vaz.

“Our observations provide a genetic basis to the understanding of mild NPDR and development of CSME suggesting a different pathophysiology for each different phenotype,” he concluded.