Endothelial NOS gene Glu298Asp polymorphism in preterm neonates with respiratory distress syndrome

Rationale: Respiratory Distress Syndrome (RDS) due to prematurity is one of the most important causes of morbidity and mortality in Neonatal Intensive Care Units. According to few studies in recent years, endothelial nitric oxide synthase (eNOS) gene polymorphisms are found to be partially responsible for liability to RDS. The purpose of this study was to determine the association between eNOS gene polymorphism and RDS in preterm neonates.

Patients and methods: The patient group consisted of 152 premature neonates born before 37 weeks of gestation and diagnosed as RDS. The control group consisted of 125 premature neonates born before 37 weeks of gestation, but was not diagnosed as RDS. Genomic DNA from patients and controls was analyzed by polymerase chain reaction.

Results: It was found that Glu/Glu, Glu/Asp, and Asp/Asp genotype frequencies of the eNOS gene polymorphism were 35.2%, 59.2%, and 5.6% of the control group, and 32.9%, 65.1%, and 2.0% of the patient group, respectively (P > 0.05). However, significant increases in Glu/Glu genotype and Glu allele frequencies were noted in the RDS groups when the preterm neonates were divided into two groups (24-30 weeks and 31-36 weeks) by gestational age. Additionally, Glu/Asp genotype and Asp allele were markedly less frequent among the RDS groups (P < 0.05). Asp allele frequency in boys and Glu allele frequency in girls were significantly high in RDS group (P < 0.05).

Conclusions: These data suggest that there were significant gestational age-related differences between RDS and control groups in terms of Glu298Asp polymorphism. Therefore, RDS seems to develop with alterations in eNOS Glu298Asp genotype frequencies in the Turkish population.