Vascular endothelial growth factor gene polymorphisms as prognostic markers for ocular manifestations in pseudoxanthoma elasticum

Abstract

Pseudoxanthoma elasticum (PXE) is a heritable disorder affecting the skin, eyes and cardiovascular system. It is caused by mutations in the ABCC6 gene and its clinical picture is highly variable. PXE often leads to severe visual impairment due to the development of choroidal neovascularisation (CNV). CNV in PXE-associated retinopathy is believed to be mediated by the action of vascular endothelial growth factor (VEGF). The objective of the present study was to evaluate a possible impact of variations in the VEGFA gene on ocular manifestations of PXE. For this purpose, we evaluated the distribution of 10 single nucleotide polymorphisms (SNPs) in the promoter and coding region of the VEGFA gene in DNA samples from 163 German patients affected by PXE and in 163 healthy control subjects. Haplotype analysis of SNPs c.-1540A>C, c.-460C>T, c.-152G>A, c.405C>G, c.674C>T, c.1032C>T, c.4618C>T and c.5092C>A revealed that the haplotype CTGGCCCC was associated with PXE (OR 2.05, 95% CI 1.33-3.15, P(corrected) = 0.01). Furthermore, five SNPs showed significant association with severe retinopathy. The most significant single SNP association was c.-460C>T (OR 3.83, 95% CI 2.01-7.31, P(corrected) = 0.0003). Logistic regression analysis identified the c.-460T and the c.674C alleles as independent risk factors for development of severe retinopathy. Our findings suggest an involvement of VEGF in the pathogenesis of ocular PXE manifestations. VEGF gene polymorphisms might prove useful as prognostic markers for the development of PXE-associated retinopathy and permit earlier therapeutic intervention in order to prevent loss of central vision, one of the most devastating consequences of this disease.