Comparison of surfactant protein B polymorphisms of healthy term newborns with preterm newborns having respiratory distress syndrome

Abstract

Polymorphisms and mutations in the surfactant protein B (SP-B) gene have been associated with the pathogenesis of respiratory distress syndrome (RDS). The objective of the present study was to compare the frequencies of SP-B gene polymorphisms between preterm babies with RDS and healthy term newborns. We studied 50 preterm babies with RDS (inclusion criteria -newborns with RDS and gestational age between 28 and 33 weeks and 6 days), and 100 healthy term newborns. Four SP-B gene polymorphisms were analyzed: A/C at nucleotide -18, C/T at nucleotide 1580, A/G at nucleotide 9306, and G/C at nucleotide 8714, by PCR amplification of genomic DNA and genotyping by cRFLP. The healthy newborns comprised 42 female and 58 male neonates; 39 were white and 61 non-white. The RDS group comprised 21 female and 29 male preterm neonates; 28 were white and 22 non-white. Weight ranged from 640 to 2080 g (mean: 1273 g); mean gestational age was 31 weeks and 2 days (range: 28-33 weeks and 6 days). When white children were analyzed separately, a statistically significant difference in the G/C polymorphism at 8714 was observed between groups (P = 0.028). All other genotype frequencies were similar for both groups when sex and race were analyzed together. Analysis of the SP-B polymorphism G/C at nucleotide 8714 showed that among white neonates the GG genotype was found only in the RDS group at a frequency of 17% and the GC genotype was more frequently found in healthy term newborns. These data demonstrate an association of GG genotype with RDS.

Surfactant protein B gene polymorphism in preterm babies with respiratory distress syndrome

“…This result differs from a study by another laboratory where the AG genotype was considered to be a risk factor for RDS (7). In our 2007 study on a population of healthy term and preterm newborns from the city of São Paulo, we did not find a protective effect of the AG genotype (30).…”

“…In 2007, we studied the same four polymorphisms in a group of 100 healthy term babies and a group of 50 preterm babies with RDS (30). When race was analyzed separately, among the white individuals, the GG genotype was only found in the RDS group.…”

Clinical, radiological and genetic analysis of a male infant with neonatal respiratory distress syndrome

“…There have been a number of preliminary investigations into the genetic susceptibility of neonatal RDS (1,15). The effect of hereditary factors on neonatal RDS was previously studied.…”

“…Previous results indicate that intron 4 length variants affect SP-B mRNA splicing and that this may contribute to lung disease (6). Polymorphisms and mutations in the SP-B gene are associated with the pathogenesis of respiratory distress (15). Several studies have demonstrated that deletion variants of intron 4 affect SP-B gene expression (3,4,6); however, SP-B intron 4 variant frequencies have no detectable association with RDS in Brazilian and Finnish populations (1,16).…”

Correlation between surfactant protein B mRNA expression and neonatal respiratory distress syndrome

“…Results of another study have shown the incidence of SP-B deficiency in African Americans to be higher than in Caucasian Americans (12). The SP-B gene mutation has been shown to be associated with some respiratory diseases, including neonatal RDS, acute respiratory distress syndrome, congenital pulmonary alveolar proteinosis, adult chronic obstructive pulmonary emphysema and chronic lung diseases in children (13–15). …”