Csx/Nkx2.5基因在胚胎心脏的表达及在先天性心脏病中的突变检测

目的 了解Csx／Nkx 2．5基因在胚胎心脏发育过程中的表达情况及在先天性心脏病（先心病）患者中的突变情况。方法 采用免疫组化方法检测Csx／Nkx 2．5基因表达，采用PCR-SSCP-银染和DNA测序技术检测Csx／Nkx 2．5基因突变。结果Csx／Nkx 2．5基因在心房、小梁网中高表达。16周后心房表达趋于稳定，小梁网的表达稍有下降。在心室的表达早期较弱，逐渐升高，13至16周增加幅度最大，16周后表达趋于稳定。心外膜不表达。在126例先心病患儿、16例先心病胎儿和30例正常人中发现编码21位氨基酸密码子的第3位碱基的三种多态性：A、G、A／G。结论 Csx／Nkx 2．5基因在胚胎心脏发育过程中的表达有严格的时空规律，说明该基因在心脏发育过程中发挥重要作用。本研究中，无论是散发性或家族性先心病病例，均未检测到与先心病有关的突变。

Csx/Nkx 2. 5 gene expression in embryonic hearts and its mutation in congenital heart disease

Objective To explore the Csx/Nkx 2.5 gene expression in the heart during the embryonic period and its mutation in subjects with congenital heart disease(CHD). Methods Immunohistochemistry was used to reveal the Csx/Nkx 2.5 gene expression, and PCR-SSCP-silver staining and DNA sequencing for mutation. Sixty-three embryos or fetus, 126 children with congenital heart diseases and 30 normal controls were included in the study. Results Elevated expression of Csx/Nkx 2.5 gene was found in atrium and trabecular of ventricle. After 16 weeks of gestation, the expression in atrium was stable, while slightly reduced in the trabecular. The expression in the ventricle was lower than that in the atrium in early embryonic stage followed by continuous increase which was most remarkable in 13~16 weeks and kept stable after 16 weeks. No expression of Csx/Nkx 2.5 was detected in epicardium. Three different kinds of gene polymorphisms in the third base of the 21st amino acid codon were found in all subjects:A,G,A/G. Conclusions Gene Csx/Nkx 2.5 plays an important role during the fetal heart development and its expression varies in different parts of the heart during different period in fetal development. Neither the sporadic nor the CHD cases showed any mutations in this study.