Association of age-related macular degeneration with polymorphisms in vascular endothelial growth factor and its receptor

Objective: To analyze the association between age-related macular degeneration (AMD) and polymorphisms in vascular endothelial growth factor (VEGF) and VEGF receptor KDR gene polymorphisms. A complex, multifactorial disease in which genetic and environmental factors interact, AMD is the leading cause of blindness in the elderly. Vascular endothelial growth factor (VEGF), a key regulator of angiogenesis, is considered an important factor for the pathogenetic processes of AMD. Previous studies investigated the possible association between VEGF-A gene polymorphisms and AMD, with contrasting data. No study examined the possible role of VEGF receptor KDR gene polymorphisms.

Design: Case-control study.

Participants and controls: We enrolled 226 AMD cases and 248 controls from an ophthalmology hospital center.

Methods: Genotypying for 16 polymorphic markers (single nucleotide polymorphisms [SNPs]) in VEGF-A and KDR genes.

Main outcome measures: Distribution of genotypes in AMD cases and controls.

Results: Two polymorphisms (rs833069 in intron 2 of the VEGF-A gene, rs2071559 in the promoter of the KDR gene) were significantly associated with risk of AMD. In particular, for VEGF-A rs833069 the AMD risk was increased >5-fold for G homozygotes compared with homozygous carriage of the A allele. For KDR rs2071559 the AMD risk was increased >3-fold for T homozygotes compared with homozygous carriage of the C allele. Carriers of risk alleles for both markers have a >6-fold increased risk of AMD with respect to carriers of non-risk alleles.

Conclusions: We expand previous data on the association of AMD with VEGF-A gene variations and identify for the first time an association with variations in the KDR gene. Because the SNP-604T-bearing KDR promoter has higher transcription activity, our findings further support the role of the VEGF pathway in the pathophysiology of AMD. It is possible that applications of haplotype/genotype analysis in these genes will play a role in risk assessment and pharmacogenomic approaches to AMD diagnosis and management.