Association of NOS3 tag polymorphisms with hypoxic-ischemic encephalopathy

AIM To test the association of NOS3 gene with hypoxic-ischemic encephalopathy (HIE). METHODS The study included 110 unrelated term or preterm born children (69 boys and 41 girls) with HIE and 128 term and preterm born children (60 boys and 68 girls) without any neurological problems after the second year of life. Children with perinatal HIE fulfilled the diagnostic criteria for perinatal asphyxia. All children were admitted to the Clinical Hospital Split between 1992 and 2008. We analyzed 6 tagging single nucleotide polymorphisms (SNP) within NOS3 gene (rs3918186, rs3918188, rs1800783, rs1808593, rs3918227, rs1799983), in addition to previously confirmed NOS3-associated SNP rs1800779. Genotyping was conducted using real-time polymerase chain reaction (PCR). Association analyses were performed according to allelic and genotypic distribution. RESULTS Allelic test did not show any SNP association with HIE. SNP rs1808593 showed genotype association (P=0.008) and rs1800783-rs1800779 TG haplotype showed an association with HIE (P<0.001). The study had 80% statistical power to detect (α=0.05) an effect with odds ratio (OR)=2.07 for rs3918186, OR=1.69 for rs3918188, OR=1.70 for rs1800783, OR=1.80 for rs1808593, OR=2.10 for rs3918227, OR=1.68 for rs1800779, and OR=1.76 for rs1799983, assuming an additive model. CONCLUSION Despite the limited number of HIE patients, we observed genotypic and haplotype associations of NOS3 polymorphisms with HIE.