A Clinical Study Of The Value Of Serum Enzymology Combined With Genetic Testing In The Early Diagnosis Of Children With Pseudohypertrophic Macromuscular Dystrophy

Objective: To investigate the clinical characteristics and early diagnostic value of serum enzymatic indexes in different gene mutation types,different gene mutation sites,and different age stages in children with Pseudohypertrophy macromuscular dystrophy which is divided into Duchenne muscular dystrophy(DMD)and Becker muscular dystrophy(BMD),in order to provide a basis for the accurate diagnosis of DMD/BMD.Methods: According to the criteria for inclusion and exclusion,138 cases of clinically relevant data of children with pseudo-hypertrophic macromuscular dystrophy were retrospectively collected from September 2013 to October 2020,and their serum enzymatic indicators,gene mutation types,mutation sites,different ages and EMG results were statistically analyzed,and the receiver operating characteristic curve(ROC curve)was used to analyze the early diagnostic value of serum enzymology for DMD/BMD.Results : There were 138 children with DMD/BMD diagnosed by comprehensive examinations such as anti-amyotrophin gene(Dystrophin gene)testing,and the age of medical treatment was mainly preschool age,the average age was(3.75±2.75 years),and the median age was 3 years old.Among them,83 children with DMD and 55 children with BMD were diagnosed.Among the 138 children with DMD/BMD,108 cases were Dystrophin gene deletion mutations,of which 71 cases had exon 44-54 deletions,accounting for 65.7%;exon 8-9,exon 44,exon 49-50 mutations appeared 5 times each;25cases were repetitive mutations,and 5 cases were point mutations.Among the 90 children with EMG,40 cases showed no abnormalities and 50 cases suggested myogenic damage,of which 42 cases of deletion mutations,7 cases of duplication mutations,1 case of point mutations,and the difference in EMG results of children with three types of mutations was not statistically significant(p>0.05).The results of the U test of serum enzymatic indicators in children with myogenic impairment and normal emography showed that the serum enzymatic indicators of children with myogenic impairment on electromyography were higher(p<0.05).There were no significant differences in serum enzymology levels between groups of children with different functional divisional gene mutations of antimuscular atrophy protein(p>0.05).There were no significant differences in serum enzymatic levels at different ages(p>0.05),but it can be seen that all serum enzymatic changes showed a tendency to increase first and then decline with the progression of age,peaking between 6 and 9 years.Among the 138 children,82 were dystrophin with extrabox mutations,among them,66 children with DMD(80.5%)and 16 children with BMD(19.5%);49 were children with intra-frame mutations,among them,13 children with DMD(26.5%)and 36 children with BMD(73.5%).Two new deletion mutations were not clear about the type of out-of-frame or in-frame mutation and five cases of point mutations did not cause reading frame changes,so they are excluded.The H test results of serum enzymatic indexes in children with in-frame mutation and extra-frame mutation showed that the serum enzymatic index levels of children with extra-frame mutation were significantly higher than the serum enzymatic index levels(p<0.05)in children with intraframe mutations,and further ROC curve analysis found that when serum creatine kinase kinase(CK)was greater than 8251U/L,creatine kinase isoenzyme MB,CKMB)was greater than 184.35U/184.35U/ L,lactate dehydrogenase(LDH)greater than 820.5U/L,aspartate aminotransferase(AST)greater than 143.5U/L,alanine aminotransferase(ALT)greater than 193U/L,myoglobin(Myo)greater than 237.6 ug/L,suggesting that the gene mutation is an out-of-frame mutation,which is more common in clinical practice with DMD.Conclusion: 1.Serum CK,CKMB and Myo are reliable biological indicators of Pseudohypertrophy macromuscular dystrophy,and have the value of DMD/BMD preliminary screening and auxiliary diagnosis.2.Dystropin gene examination of children with DMD/BMD can show deletion mutations,duplication mutations and point mutations,and deletion mutations are more common,and genetic testing is the gold standard for confirming DMD/BMD.3.When testing CK>8251U/L,Myo>237.6ug/L,the DMD/BMD gene mutation is indicated as an extra-frame mutation,and DMD is more common in clinical phenotype.