[Genetic polymorphism of surfactant protein A in neonatal respiratory distress syndrome].

OBJECTIVE

To investigate the characteristics of gene expression of surfactant protein A in Chinese premature infants and the association between surfactant protein A and the risk of neonatal respiratory distress syndrome (RDS).

METHODS

Vein-blood samples (2 mL) from 18 Chinese premature infants with RDS and 28 controls were assayed for SP-A genotypes 6A2, 6A3, 1A0 and 1A1 by SSCP.

RESULTS

The frequency of allele distribution of SP-A1 allele 6A2 and 6A3 was 0.50 and 0.056 respectively in the RDS group and was 0.214 and 0.107 in the control group. Compared with the controls, SP-A1 allele 6A2 was over-represented in the RDS group (P<0.05). In contrast, SP-A1 allele 6A3 tended to be under-represented in the RDS group but there was no statistical difference when compared with the controls. The frequency of allele distribution of SP-A2 allele 1A0 and 1A1 was 0.722 and 0.667 respectively in the RDS group and was 0.679 and 0.821 respectively in the control group. There were no significant differences in the distribution frequency of SP-A2 allele 1A0 and 1A1 between the two groups. In the infants born at gestation >32 weeks, SP-A1 allele 6A2 was over-represented in the RDS group compared with the control group (frequency: 0.56 vs 0.15; P<0.05).

CONCLUSIONS

The frequency of SP-A1 allele 6A2 and 6A3 was low, in contrast, the frequency of SP-A2 allele 1A0 and 1A1 was high in normal Chinese premature infants. SP-A1 allele 6A2 may be a susceptible gene for RDS.