Relationship between VEGFA polymorphisms and serum VEGF protein levels and recurrent spontaneous miscarriage

Is recurrent spontaneous miscarriage (RSM) associated with changes in vascular endothelial growth factor (VEGF) serum levels, and with polymorphisms in the VEGFA gene? Reduced serum VEGF levels, and VEGFA 460T/C (rs833061), 398G/A (rs833068), 583T/C (rs3025020) variants, were associated with RSM. Reduced expression of VEGF has been linked with spontaneous miscarriage, likely due to defective fetal and placental angiogenesis. Since VEGF production is in part inherited, VEGFA polymorphisms associated with altered VEGF secretion have been investigated for their association with RSM, often with variable conclusions. A retrospective casecontrol study, which was conducted between January 2011 and April 15, 2012. Subjects comprised 296 women with RSM (mean age: 31.6 5.4 year), and 305 age-matched (mean age: 31.6 4.9 year) control Arab women, who had attended outpatient obstetrics and gynecology clinics in two teaching hospitals in Bahrain. VEGFA 2578C/A (rs699947), 460T/C (rs833061), 1154G/A (rs15703060), 634G/C (rs2010963), 398G/A (rs833068), 497G/A (rs833070), 583T/C (rs3025020) and 936C/T (rs3025039) genotyping was done by real-time PCR, with defined clusters; VEGF serum levels were measured by ELISA. Higher minor allele frequency (MAF) and genotype distribution of 460T/C [corrected P (P-c) 0.003], 398G/A (P-c 0.016) and 583T/C (P-c 0.001) single nucleotide polymorphisms (SNPs) were seen in RSM cases than control women. Increased RSM risk was seen with homozygous 460T/C and 398G/A SNPs and with heterozygous 583T/C, which had a stronger effect when homozygous. Serum VEGF levels were significantly reduced in RSM cases compared with control women (P 0.016), and correlated with 460T/C, 398G/A and 583T/C genotypes. Haploview analysis revealed heterogeneity in linkage disequilibrium between VEGFA variants, and two blocks were identified: Block 1 comprising 2578C/A, 460T/C and 1154G/A, while Block 2 contained 634G/C, 398G/A, 497G/A, 583T/C and 936C/T. Both negatively and positively RSM-associated 3-locus (Block 1) and 5-locus (Block 2) VEGFA haplotypes were identified, after controlling for a number of covariates. The study was retrospective and can only demonstrate association and not a causeeffect relationship. Furthermore, it was limited to Bahraini Arabs,thereby necessitating parallel studies on other ethnic groups. Reduced VEGF secretion, and specific VEGFA variants may contribute to the pathogenesis of RSM. However, the association of VEGFA SNPs with RSM appears to be independent of their association with altered VEGF serum levels. The differential association of VEGFA variants with RSM is in line with previous findings on the contribution of ethnicity/racial background to genetic association studies.