A Study On The Genetic Mutation And The Protein Expression Of Dystrophin Gene

Objectives Improve the multiple ligation probe amplification technology.And combined with histological staining techniques and immunohistochemical techniques,to raise the detection rate of genetic mutation and female carries based on the platform of detect pseudohypertrophic muscular dystrophy with MLPA.To investigate the clinical value of differential diagnosis DMD/BMD,and the correlation of genetic mutation with protein expression of dystrophin gene in the patients with DMD/BMD.Methods To detect the copy number of 79 exons in dystrophin gene for 198 patients,who examined at Genetic Diagnosis Center of First People's Hospital of Yunnan Province from January 2013 to December 2015.Observed the morphological characteristics of gastrocnemius muscle with muscle biopsyin,and distinguished the muscular dystrophy with other muscle diseases.Detected the dystrophin expression in gastrocnemius muscle by immunohistochemistry,and differential diagnosis DMD/BMD.Results Detected the genetic mutation of dystrophin gene for 198 patients using MLPA.Checked out different mutations in 128 cases,and the detection rate is 64.65%.Of 160 male patients,95 deletion mutation and 6 repeat mutation were detected out,the deletion mutation detection rate is 59.38%and the repeat mutation detection rate is 3.75%.Of 38 female patients,25 deletion mutation and 2 repeat mutation were detected out,the deletion mutation detection rate is 65.79%and the repeat mutation detection rate is 5.26%.Analysis the results,find that the regions of the highest mutation frequency focused on the exon 45-54,account for 46.59%.And 109 cases in which mutations occur in the central region of the rod(including 104 cases of deletion mutants,5 cases of duplication mutations),account for 85.16%(109/128 cases),this is consistent with previous literature.Of 128 cases,who detected out mutations,95 cases belong to out-of frame,28 cases belong to in frame,and the mutations of the other 5 cases relate to exonl or exon 79,so the impaction on the structure of the reading frame is not clear.Of 38 female cases,9 cases have DMD/BMD family history(7 cases detected out mutation carrying,and 2 cases are duplication mutation in this 7cases)9 and 29 cases have the birth history of DNMD/BMD children(20 cases detected out mutation carrying,and 9 cases were not.And of these 9 cases,the children of 4 cases were not detected out mutation).Of 25 patients,who inspected with muscle biopsyin,the morphological characteristics of gastrocnemius muscle of 14 patients coformed to the psthological changes of muscular dystrophy.The others,morphological characteristics are in keeping with the psthological changes of hematoma or polymyositis.The 14 patients who are diagnosed as muscular dystrophy,taked the immunohistochemistry further.The results showed that:dystrophin were not detected in 11 DMD cases(3 cases with dystrophin gene deletion,and 8 cases who not detected out genetic mutation)and decreased in 3 BMD cases(who not detected out genetic mutation).Conclution MLPA can be quickly and accurately in detecting the mutations in dystrophin gene,no matter the deletion or repeat mutation for the single or multiple exons,or in detecting the female carries.But about 30%mutation still cannot be detected out.While,the dystrophin protein expression in gastrocnemius muscle can be detected with immunohistochemistry.Therefore,it is very important for differential diagnosis the DMD/BMD,to combine the MLPA,the muscle biopsy and the immunohistochemistry.And it also can provide the basis for the treatment and prognosis for patients.