ABSTRACT
Objective To explore the association between genetic variants in intron 4 of the surfactant protein B(SP-B) gene and neonatal respiratory distress syndrome(NRDS) in preterm infants.Methods Using 1 ∶ 1 casc-control study method,a cohort of 52 preterm infants with NRDS and 52 preterm infants without NRDS(non-NRDS) were recruited.Within 1 week after the patients hospitalized,2 mL venous blood was collected.Genomic DNA was extracted and polymerase chain reaction(PCR) was performed to amplify the special region with conserved sequence motifs and intermotif dinucleotide repeats(CA) n in intron 4 of SP-B gene.PCR products was demonstrated by agarose gel electrophoresis and variants were identified by product size.Results A 550 bp target band could be seen in all PCR products (including NRDS group and non-NRDS group).Besides,an additional band(about 650 bp) could be seen in 3 cases of NRDS and 1 case of non-NRDS,which represented insertion variation.The variation incidence of intron 4 of SP-B gene in NRDS group and non-NRDS group were 5.77％ and 1.92％,respectively,there was significant differences (x2 =44.18,P ＜ 0.05).Conclusion Genetic variants in intron 4 of SP-B gene may contribute to risk of preterm infants with NRDS.