Objective: To detect and analyze the genetic variation in exon 7 of lung surfactant protein B (SP-B), and to investigate the relationship between the genetic variation and the incidence of neonatal respiratory distress syndrome (NRDS) in Han populations in western Inner Mongolia.
Methods: In the case-control study, 47 Han infants with NRDS were assigned to case group. All the 47 patients had the last three generations of their ancestors reside in western Inner Mongolia. Forty-seven Han newborns without NRDS were assigned to control group. PCR-based gene analysis was used to determine the mutation in exon 7 of SP-B gene and genotype and allele frequencies of the R236C site in exon 7 of SP-B gene.
Results: In Han newborns in western Inner Mongolia, there was no mutation in exon 7 of SP-B gene; two genotypes, CC and CT, were identified in the R236C site in exon 7 of SP-B gene. No TT genotype was found in the two groups. There were no significant differences in the genotype frequency of CC or CT as well as the allele frequency of C or T between the case and control groups (CC: 72% vs 85%, P>0.05; CT: 28% vs 15%, P>0.05; C: 85% vs 93%, P>0.05; T: 15% vs 7%, P>0.05).
Conclusions: There is no mutation in exon 7 of SP-B gene in Han infants with NRDS in western Inner Mongolia. There is no significant association between the gene polymorphism of the R236C site in exon 7 of SP-B gene and the incidence of NRDS in Han populations in that region.
目的: 通过检测和分析肺表面活性物质蛋白B基因外显子7（exon7）区域上是否存在基因变异，探讨其与内蒙古西部地区汉族新生儿呼吸窘迫综合征（NRDS）发病的关系。
方法: 采用病例对照研究方法，选择祖上三代都居住在内蒙古西部地区的汉族NRDS患儿47例作为病例组，选择同民族和同群体中未发生NRDS的新生儿47例为对照组。通过PCR基因分析技术检测SP-B基因外显子7区域上有无突变，以及SP-B外显子7（R236C）位点的基因型、等位基因分布。
结果: 在内蒙古西部地区汉族新生儿中，SP-B基因外显子7区域无突变发生；SP-B外显子7（R236C）位点基因型均可检出两种基因型（CC、CT），两组中均未检出TT基因型。病例组CC和CT基因型频率分别为72%和28%，C等位基因频率为85%，T等位基因频率为15%。对照组此两种基因型分别为85%和15%，C等位基因频率为93%，T等位基因频率为7%。病例组与对照组此位点基因多态性相比等位基因及基因型频率在两组之间差异无统计学意义（P > 0.05）。
结论: 内蒙古西部地区汉族NRDS患儿的SP-B基因第7外显子未发现基因突变。未发现SP-B基因外显子7（R236C）位点基因多态性与该地区汉族NRDS的发生有明显相关性。