# Investigation of UCHL3 and HNMT Gene Polymorphisms in Greek Patients with Type 2 Diabetes Mellitus and Diabetic Retinopathy

## TL;DR

This study examines how two genetic variations are linked to diabetic retinopathy risk in Greek patients with type 2 diabetes.

## Contribution

The study identifies novel associations between UCHL3 and HNMT gene polymorphisms and diabetic retinopathy in a Greek population.

## Key findings

- The rs4885322 SNP in the UCHL3 gene increases DR risk by 2.04 times.
- The rs11558538 SNP in the HNMT gene increases DR risk by 3.27 times.
- Both SNPs show statistically significant associations with diabetic retinopathy.

## Abstract

Background and Objectives: Recent studies have shed light on the association between genetic factors and diabetic retinopathy (DR) onset and progression. The purpose of our study was to investigate the association between rs4885322 single-nucleotide polymorphism (SNP) of the UCHL3 gene and rs11558538 SNP of the HNMT gene with the risk of DR in Greek patients with type 2 diabetes mellitus (T2DM). Materials and Methods: In our case–control study, we included 85 T2DM patients with DR and 71 T2DM patients without DR (NDR), matched by ethnicity and gender. Demographic and clinical data of all patients were collected, and then patients went through a complete ophthalmological examination and were genotyped for rs4885322 SNP of UCHL3 gene and for the rs11558538 SNP of HNMT gene. Statistical analysis was implemented by STATA v.16.1. Results: No significant differences in demographic and clinical data were observed between the DR and the NDR group (p-value ≥ 0.05), except for the lower mean of age, longer duration of DM, more frequent use of insulin therapy, and higher levels of hemoglobin A1c (HbA1c) in the DR group. The allelic effect of rs488532 increases the risk of DR by 2.04 times, and in the dominant genetic model, the risk of DR is elevated by 123%, while both associations are statistically significant (p-value < 0.05). Moreover, the allelic effect of rs11558538 is associated with a 3.27 times increased DR risk and, in the dominant genetic model, reveals an augmented risk of DR by 231%, while both associations are also statistically significant (p-value < 0.05). Conclusions: The rs4885322 SNP of the UCHL3 gene and the rs11558538 SNP of the HNMT gene are associated with DR risk in Greek patients with T2DM. However, further studies with larger samples and different ethnicities should be implemented to clarify the exact association of these SNPs and DR onset.