# Association of eNOS T786C genetic polymorphism with the risk of aneurysmal subarachnoid haemorrhage

## TL;DR

This study found that a specific genetic variation in the eNOS gene is linked to a higher risk of aneurysmal subarachnoid haemorrhage.

## Contribution

The study identifies the eNOS T786C polymorphism as an independent risk factor for aneurysm rupture.

## Key findings

- The CC genotype of the T786C polymorphism was more common in patients with aSAH than in those with unruptured IAs.
- Patients with the CC genotype had a higher risk of aneurysm rupture.
- Multilobular and posterior circulation aneurysms were more likely to rupture.

## Abstract

Unruptured intracranial aneurysms (IAs) are increasingly detected due to advancements in neuroimaging. Despite improvements in treatment, aneurysmal subarachnoid haemorrhage (aSAH) is associated with high mortality and morbidity. Treatment decisions for IA are complex and individualized, considering aneurysm and patient-related risk factors. Genetic factors, particularly endothelial nitric oxide synthase (eNOS) polymorphisms, have been implicated in IA formation and rupture risk.

This study investigated the association between three eNOS polymorphisms (27-bp-VNTR, T786C, and G894T) and aSAH in a cohort of 275 patients with unruptured IA or aSAH. Patients were followed for at least 8 years with clinical and imaging assessments. Genotyping of selected polymorphisms was performed, and statistical analyses were conducted to identify interactions between genetic polymorphisms and established risk factors.

A significant difference in the frequencies of genotypes and allele carriers of the T786C polymorphism was observed between patients with unruptured IA and those with aSAH, with an increased proportion of CC homozygotes in the aSAH group. The risk of rupture was higher in patients with the CC genotype. Multilobular aneurysms and those located in the posterior circulation had a higher incidence of rupture. Associations between arterial hypertension and certain genotypes were also found. However, no significant interaction was observed between the polymorphisms and established risk factors in relation to aneurysm rupture.

Our data showed a significant and independent correlation between eNOS genetic polymorphism T786C and aSAH.