Clinical Study Of Dilated Cardiomyopathy And Study On Pathogenesis Of SRCAP Gene Mutation

PurposeTo study the correlation between clinical indicators(serological indicators,imaging indicators,echocardiographic indicators,electrocardiographic indicators,etc.)of children with idiopathic dilated cardiomyopathy(DCM)and clinical prognosis;explore a child with dilated cardiomyopathy Pathogenesis of Snf2-relate CBP activator protein(SRCAP)gene mutation.Method The clinical data of children with inpatient and outpatient idiopathic DCM who came to our hospital from January 2014 to December 2018 were collected and grouped according to patient outcome: death group and survival group.Collect clinical data and blood samples of a DCM family,use whole exons sequencing(WES)technology to find the pathogenic genes,Sanger sequencing to verify the pathogenic genes,and use I-TASSER software to predict whether the pathogenic genes affect protein stability;Real-time quantitative polymerase chain reaction(RT-q PCR)and Western Blot(WB)techniques were used to investigate whether mutations in pathogenic genes affect peripheral blood m RNA levels and protein levels.Result1.In the past five years,a total of 71 children with DCM met the selection criteria,41males(57.75%),30 females,age range 1 month to 144 months,median age 12 months,and 28 patients in the death group(39.43 %).There were 43 cases in the survival group.There was no significant difference in age and gender between the two groups(P> 0.05).2.The ROSS score was statistically significant at first diagnosis between the two groups(P <0.05).3.The number of patients with cardiogenic shock at initial diagnosis was significantly higher in the death group(32.14%)than in the survival group(9.30%),which was statistically significant(P = 0.015).4.At the initial diagnosis,52 of 71 children were tested for plasma brain natriuretic peptide(n-terminal pro-brain natriuretic peptide,NT-pro BNP).According to whether the group was greater than 3500,the difference between the two groups was statistically significant(χ~2 = 9.871,P = 0.002);60 cases detected creatine kinase-muscle brain(CK-MB),54 cases detected cardiac troponin-I,c Tn I),no statistical significance in both groups(P = 0.446,P = 0.178)5.glutamic-oxaloacetic transaminase(GOT)and glutamate pyruvate transaminase(GPT)in liver function indicators at first diagnosis were statistically significant between the two groups(P = 0.006,P = 0.001),renal function indicators blood urea nitrogen(BUN)and creatinine(Cr),There were no statistical significance between the two groups(P = 0.107,P = 0.407).6.The serum sodium concentration was statistically significant between the two groups at the time of initial diagnosis(P = 0.002).The death group(134.5 ± 4.3)was significantly lower than the survival group(137.6 ± 3.9).There was no statistical significance in blood potassium and blood chlorine(P = 0.818,P = 0.915).7.Total protein and albumin were statistically significant at first diagnosis(P = 0.004,P = 0.009);globulin was not statistically significant(P = 0.135).8.The coefficient of variation of red blood cell distribution width was statistically significant between the two groups at initial diagnosis(P = 0.033);hemoglobin(HB)and hematocrit were not statistically significant between the two groups(P = 0.120,P= 0.356),but HB(108.1 ± 16.8)in the death group was significantly lower than that in the survival group(114.4 ± 16.2).9.At the initial diagnosis,body surface area normalized left ventricular end diastolic diameter(LVDd)and body surface area normalized left ventricular systolic diameter(LVDs)were statistically significant(P = 0.000,P = 0.000).At the first diagnosis,the left ventricular ejection fraction(LVEF)and fractional shortening(FS)were statistically significant(P = 0.001,P = 0.002);pulmonary artery pressure was statistically significant between the two groups(P = 0.003).10.The number of moderate to severe reflux in the mitral and tricuspid valves was significantly higher in the death group than in the survival group,and there was a statistically significant difference between the two groups(P = 0.002,P = 0.002).There was more pericardial effusion in the death group than in the survival group,and there was statistical significance between the two groups(P = 0.000).11.Two-dimensional speckle tracking imaging(2D-STI)analysis found that myocardial local strain and overall strain in children with DCM were significantly lower than those in normal people.Left ventricular basal segment anterior and lateral myocardial longitudinal strain(BAL LS),apical cap longitudinal strain,apical two-chamber heart GLS were statistically significant between the two groups(P<0.05).12.Pearson correlation analysis found that the apical three-chamber heart GLS and short-circle central myocardial global circumferential strain(GCS)were correlated with LVEF and FS(correlation coefficients were r =-0.524,r =-0.552,r =-0.563,r =-0.582;P <0.05).13.Among the 71 children,68 children had ECG results.The highest incidence of ECG was ST-T changes(82.35%),the incidence of abnormal Q waves,prolonged QT interval,prolonged PR interval,ventricular arrhythmia,atrial arrhythmia,left bundle branch block(LBBB)was 27.94%,25%,30.88%,22.06%,16.18%,10.29%,and there were no statistical significance between the two groups(P> 0.05).14.The cardiothoracic ratio(0.705 ± 0.046)in the death group was significantly higher than that in the survival group(0.643 ± 0.077),and there was statistical significance between the two groups(P = 0.002).15.Logistic regression analysis found that ROSS score at initial diagnosis,BNP greater than 3500pg/ml,moderate to severe mitral regurgitation,and moderate to severe regurgitation of tricuspid valve were independent risk factors related to death.16.A clinically diagnosed child with DCM found a gene mutation in the SRCAPc.452-453 del,p Phe151 Cysfs * 71 through the WES technology.The family confirmed that the mutation was denovo mutation through Sanger sequencing technology,and the inheritance was autosomal dominant.I-TASSER software predicts3,230 residues of wild-type protein,220 residues of mutant protein,and analysis of hydrophilic-hydrophilic were wild-type Sum(5: 3226)=-1449.44,mutant Sum(5:216)=-126.55.17.RT-q PCR detection of peripheral blood m RNA in child has no halving or fold relationship compared with parents.18.WB detection of SRCAP protein in peripheral blood,found that children with higher SRCAP protein content than their parents.Conclusion1.The mortality of 71 children with idiopathic dilated cardiomyopathy was 39.43%,and the incidence was higher in men than in women.The death was not related to the age of the first diagnosis and gender.2.Univariate analysis found that ROSS score,cardiogenic shock,NT-pro BNP>3500pg/ml,GOT,GPT,coefficient of variation of red blood cell distribution width,blood sodium,total protein,albumin,body surface area normalized LVDd,body surface area normalized LVDs,LVEF,LVFS,pulmonary pressure,moderate and severe mitral regurgitation,moderate and severe mitral regurgitation,pericardial effusion,the left ventricular basal segment anterior and lateral myocardial LS,apical cap LS,and GLS in the apical two-chamber view and cardiothoracic ratio are high risk factors for idiopathic DCM death in children.3.2D-STI found that the local myocardial strain and overall strain in children with DCM were significantly lower than those in normal people,which was consistent with the diffuse reduction of left ventricular motion seen in conventional UCG.4.2D-STI found that the apical three-chamber heart GLS and the central GCS had correlation with LVEF and FS.5.2D-STI compared with conventional UCG,the analysis of myocardial segment movement in children with DCM is more detailed,and it is more valuable in judging the prognosis of a specific DCM individual.6.The most common manifestations of ECG in children with DCM are ST-T changes(82.35%),followed by prolonged PR interval(30.88%).There is no statistical correlation between ECG changes and prognosis.However,the probability of LBBB in the death group(12%)was higher than that in the survival group(9.30%).7.Logistic regression analysis found that high ROSS scores,BNP greater than 3500pg/ml,moderate to severe mitral regurgitation,and moderate to severe tricuspid regurgitation were independent high-risk factors for death in children with DCM.When the ROSS score was ≥8,the sensitivity of death was 96.4% and the specificity was 62.8%.8.SRCAPc.452-453 del,p Phe151Cysfs*71 gene mutation is a new site mutation,there is no related report of this gene and DCM in the international.bioinformatics analysis of this mutation leads to the premature termination of peptide synthesis and truncation of protein structure,Hydrophobicity changed significantly,and the mutant was more hydrophobic than the wild type(degree: 1322.89);the software predicted that the mutation was a pathogenic mutation in children with DCM.9.SRCAPc.452-453 del,p Phe151Cysfs*71 gene mutation in children with peripheral blood SRCAP protein was significantly overexpressed.It is speculated that this gene mutation leads to changes in peripheral blood protein levels,which may be the pathogenic mechanism of DCM.10.SRCAPc.452-453 del,p Phe151Cysfs*71 gene mutation does not affect the expression of m RNA level.It is speculated that this gene mutation may affect protein expression through post-transcriptional modification.