Study On The Mutation And Expression Of Nkx2-5 Gene In Human Simple Congenital Heart Disease

ObjectiveCongenital heart disease(CHD) is a common newborn defect,affecting approximately 1% of infants.As a disease of multifactorial inheritance,CHD is caused by genetic factors in embryonic phase and environmental factors.However,the pathogenisis is still not clear.The clinical data and epidemiological study indicate that the genetic factors play an important role in the pathogenesis of CHD.So identifying genes involved in the cardiac development from the molecular lever is very important to find out the mechanism of CHD and make a better therapeutic program.Nkx2-5 gene is found out recently that it is the transcription factor expresses earliest during heart development in all vertebrate.Its abnormality will cause various CHD.Nkx2-5 mutation was proved exist in CHD in 1998.Now,most scholars think that the mutation of Nkx2-5 will decrease the transcript activity of transcription product and prevent other associated factors to produce effect.This will affect heart development,then CHD happens.Previous study thought that CHD patients without blood relationship rarely have the same gene mutation.Recently,foreign scholars think that Nkx2-5 mutation in CHD has somatic character,also called mosaicism of mutation.We investigated the mutation and expression of Nkx2-5 gene in human simple CHD so as to clear relationship of the mutation and simple CHD.MethodWe designed primers of 2 exons of Nkx2-5,the examined the mutations of coding sequence of Nkx2-5 gene in 30 myocardium samples from fetuses with simple CHD by PCR single strand conformation polymorphism(PCR-SSCP);Using P-actin as internal control,we detected the differential expression between 30 myocardium samples from simple congenital heart disease fetuses and 30 normal controls by reverse transcription polymerase chain reaction (RT-PCR).ResultsNo mutation was detected in 2 exons of Nkx2-5 gene in all samples by PCR-SSCP;The mRNA expression levels of Nkx2-5 show descent tendency in samples of simple CHD compared with normal controls.ConclusionMutations in coding region of Nkx2-5 gene may not have the somatic cell character;The abnormality in transcription level of Nkx2-5 gene may be a kind of mechanism causing human simple CHD.