Endothelial nitric oxide synthase gene polymorphisms in Fabry's disease

The gene encoding endothelial nitric oxide synthase (eNOS) is involved in abnormalities in nitric oxide (NO) synthesis that mediates functional damage of vascular cells, especially of endothelial cells (ECs), a common characteristic in cardiovascular diseases. In Fabry's disease, the characteristic mutation in the alpha-galactosidase A (alpha-gal A) gene induces large deposits of glycosphingolipids, particularly concentrated in ECs, a process associated with endothelial dysfunction. To determine whether in addition to alpha-gal A gene mutations, eNOS genetic variations are implicated in this process, we examined the genotypes of the missense Glu298Asp (G894T) variant in exon 7 and 27-bp tandem repeats in intron 4 (4b/a) in 19 patients with Fabry's disease, and 39 normal volunteers. The results showed that both varials have a significant association with Fabry's disease. The frequencies of mutant Glu/Asp + Asp/Asp genotypes and Asp allele are significantly higher in Fabry's disease (68.4%, p = 0.044, and 47.4%, p = 0.022, respectively) than in controls (46.7% and 25%, respectively). The frequencies of eNOS 4b/a polymorphisms are also significantly different in Fabry's disease when compared to controls. The mutant 4b/a + 4a/a genotype frequencies are 55.5% (p = 0.032) and 4a allele 27.8% (p = 0.05) compared with controls (23.1% and 12.8%, respectively). These results indicate that more than half of the patients with Fabry's disease carry the Glu298Asp variant (∼ 68%) and/or the 4b/a polymorphism (∼ 55%). To the best of our knowledge, this is the first report showing an influence of eNOS gene polymorphisms in patients with Fabry's disease.