【作者】 刘明颖；

【导师】 李辉；

【作者基本信息】 中国医科大学 ， 妇产科学， 2009， 硕士

【摘要】 目的先天性心脏病(congenital heart disease,CHD)是胎儿期心脏及大血管发育异常而致的先天畸形,是一种最常见的出生缺陷,严重危害婴幼儿健康,发病率接近1%,在流产儿和死胎中则高达10%,在新生儿非感染性死亡疾病中占首位。80%的先天性心脏病表现为单纯性先天性心脏病(即不伴有其他系统的先天异常),其中圆锥动脉干畸形占1/4-1/3。多年来已经证实CHD是一种多基因遗传病,主要由于胚胎期遗传因素和环境因素共同作用导致心脏血管异常发育所引起的,遗传度为55%-65%。JAG1基因编码Notch家族受体配体蛋白jagged1蛋白,该基因在人类胚胎发育中起着重要作用,主要在心血管系统表达,突变率较高,目前已发现有200余种突变存在。国外研究认为JAG1基因是Alagille综合征(Alagillesyndrome,AGS,先天性肝胆管发育不良综合征,主要包括5个特征性表现:小叶间胆管缺乏、周围肺动脉狭窄、蝶样椎骨、角膜后胚胎环以及特殊面容)的致病基因,而在CHD中的研究尚局限于AGS中,有关JAG1基因与单纯性CHD的相关性尚未见明确报道。因此,本研究通过筛查该基因在单纯性CHD心肌组织中的突变及表达情况,探讨JAG1基因与单纯性CHD发病机制的关系。方法采用PCR-SSCP(polymerase chain reaction and single strand conformationpolymorphism,PCR-SSCP,聚合酶链反应-单链构象多态性)方法对30例单纯性CHD引产胎儿心肌组织进行JAG1基因外显子2、4、5、6的突变筛查;以β-actin为内对照,采用RT-PCR方法检测JAG1基因在单纯性CHD心肌组织中的表达情况。结果所有单纯性CHD引产胎儿心肌组织标本中所选的4个外显子PCR扩增产物经SSCP检测后,未发现体细胞突变;与正常心肌组织相比,单纯性CHD引产胎儿心肌组织中JAG1基因mRNA表达呈下降趋势(P<0.05)。结论1、JAG1基因外显子2、4、5、6编码区的突变可能不是单纯性CHD的致病原因。2、JAG1基因转录水平的异常可能是其参与CHD发生的一种潜在机制。更多还原

【Abstract】 ObjectiveCongenital heart disease(CHD) is a kind of congenital malformation caused by heart and major vessels ’ abnormal development in fetal period.It is a kind of most common newborn defects,affects approximately 1%of infants,its incidence is estimated at close to ten times that level among abortus and stillbirths.CHD is the most common cause of noninfectious death in newborns.80%of CHD appears isolated CHD (other systems are normal).About 1/4-1/3 of CHD are conotruncal heart malformation. Studies have proved that CHD is a cardiac and vascular malfomation of multifactorial inheritance,which caused by genetic factors in embryonic phase and environmental factors,and the heritability is from 55%to 65%.JAG1 gene encodes a ligand of Notch receptor in the evolutionarily conserved Notch signaling pathway.It is very important in the embryonic development of homo-spapiens,it expresses in cardiovascular system mainly,the mutation rate is higher than other genes,now,there are more than 200 kinds of mutations have been found.The rearches of aboard presume that JAG1 gene is the virulence gene of Alagille syndrome(AGS,the major symptoms are:cholestasis, vertebral deformity,heart malformations,ocular defects and peculiar facial appearance), and the researches about JAG1 gene on CHD are limited in AGS,there are little identified reports are seen about JAG1 gene in isolated CHD.Through screening the mutations of JAG1 gene in isolated CHD and analyzing the expression levels of JAG1 gene in the cardiac muscular tissues,we want to approach the relationships between JAG1 gene and the pathogenesies in isolated CHD.MethodScreen the mutations of the coding sequences of JAG1 gene in 30 myocardium samples from the fetuses with isolated CHD by PCR-SSCP method;Using P-actin as internal control,we detected the differential expression between 30 myocardium samples from isolated CHD fetuses and 30 normal controls by reverse transcription polymerase chain reaction(RT-PCR).ResultsNo mutations were detected in exon2,4,5,6 of JAG1 gene in all samples by PCR-SSCP;The mRNA expression levels of JAG1 gene show descendent tendency in the samples of isolated CHD compared with normal controls.Conclusion1.Mutations in coding regions of exon2,4,5,6 of JAG1 gene may not cause human isolated congenital heart disease.2.The abnormality in transcription level of JAG1 gene may be a kind of mechanism causing human isolated congenital heart disease.更多还原