The Study Of Clinic And Muscle Pathology In Patients With Becker Muscular Dystrophy

Background：The clinical manifestations of Becker Muscular Dystrophy (BMD) were similar toDMD, But it was a benign sex chain genetic muscular dystrophy, because it was late onset,Slowly Progressing, and the prognosis was good. It was male predominant, female is mostgene carriers, and its morbidity was1/12000. Becker proposed it firstly in1957, and itsDisease-causing gene was located at Xp21.1-21.3, also the allelic genes of DMD. Recently,there were no effective treatments to treat this disease, Treatment was still hope that earlydiagnosis and early treatment. Along with the immunohistochemical stains technology andgene diagnosis technology, the rate of the early stages of the disease diagnosis was greatlyimproved, and for its treatment opened up a new path. At present, there were relatively fewthe domestic research reports about BMD, and its clinical manifestation, serum creatinekinase change rule and muscle pathology research still lacked of systematicallyunderstanding.Objectives:To find the BMD clinical manifestations, serum creatine kinase change rule andpathological features, in order to provide reference for clinical diagnosis of opinion,25casesof BMD patients with clinical and pathological features and serum creatine kinase wereresearched.Materials and Methods:Using a retrospective study method, data from July2006to January2012, Departmentof Neurology, First Hospital of Jilin University, in and out-patients, a total of35cases, BMDgroup of25cases, Control group of8cases whose the result of muscle biopsy was normal.All the35cases including BMD patients and the normal collected the clinical data: gender,age, medical history, course of the disease, symptoms, signs, serum enzyme level, musclepathology, and summarized and analysed the relevant clinical, serologic muscle enzyme andthe muscle pathology change, and then evaluated the myofiber of BMD and normal controlgroup by morphometry and statistical analysis to draw the corresponding conclusion.Results:All cases included19male, accounting for76%;6female cases, for24%, and male had larger share, the onset ages was5to15years old, totaled16, accounting for64%of the totalcases. The cases starting with double lower extremities atony was most, accounting for60%,3cases were only found myocardial enzyme increased, but not with clinical symptoms.There were20cases appearing muscle atrophy, including eighteen patients appearing lowerlimb proximal muscle atrophy, accounting for72%; special signs were mostly gastrocnemiushypertrophy and Gower sign, accounting for92%and84%respectively. serum muscleenzyme level of25cases fluctuated range for450~13954U/L, and the range was very large,with7~15years old when serum CK level reaching to peak(8848.0U/L), later with the agegrowth was on the decline; there was no correlation between muscle enzyme level andprogression. The pathology results of25cases included muscle fiber necrosis (92%), musclefiber regeneration (48%), muscle membrane nuclear increase (52%), the centronucleus(64%), opaque fiber (68%) were high frequency. Dystrophin monoclonal antibody stainingof25BMD cases mostly performanced for part of the muscle fiber membranehyperchromatic, part of muscle fiber not shading, showing Mosaic shape distribution; A fewmuscle fiber membrane dystrophin loss, most muscle fiber shading good; Uneven coloringof muscle, showing patchy distribution. The results of dystrophin monoclonal antibodiesincluding Dystrophin-N、-R、-C，showed all the three immunostaining methods expressedabnormal for15cases, accounting for60%of the total cases; any two kinds of the threedyeing methods abnormal for7cases, for28%; just one abnormal was3cases, only for12%. Three cases with α-sarcoglycan monoclonal antibody staining also presented thepositive and negative fiber distributing like checkerboard sample, accounting for12%of thetotal cases. pathological slices of25BMD cases after NADH-TR dyeing were divided intotypeⅠ andⅡ muscle fiber,and measured their area, perimeter, equivalent circle diameter,maximum diameter, minimum diameter respectively. After statistical analysis, there weresignificant difference between the parameters of type Ⅰm uscle fibers and the normal controlor type Ⅱ muscle fiber (P <0.05); however, the parameters between type Ⅱmuscle fiberand the control group was not statistically significant (P>0.05).Conclusion:1. BMD patients general onset ages were5to15years old, male predominant, and mostof BMD was sporadic cases.2. The early symptoms of BMD patients were most double lower extremities atony,performed mostly by lower limbs proximal atrophy, accompanying mostly gastrocnemiusmuscle hypertrophy and Gower sign. 3. The serum creatine kinase（CK）significantly increased in BMD patients, reacheddozens of times of the normal, with7~15years old when peak, gradually declined with ageafter then, but didn’t change as the progression to a certain degree extent.4. There were some significant pathological changes in BMD patients, for examplemuscle fiber necrosis and regeneration, muscle membrane nuclear increase, thecentronucleus, opaque fiber etc. others were less such as the lobulated fiber, moth-eaten fiber,hypertrophy of muscle fiber, fiber splitting, muscle mesenchyme connective tissuereplacement.5. The dystrophin monoclonal antibody staining of BMD cases mostly performancedfor the dystrophin of the muscle fiber membrane understain, and the discontinuity or positiveand negative fiber showing mosaic shape distribution; At the same time,3cases with lack ofα-sarcoglycan may be abnormal dystrophin influencing α-sarcoglycan expression.6. After morphometry and statistical analysis, Type Ⅰmuscle fiber atrophy was obviousin BMD cases.