| Objective:Myotonic dystrophy(DM)which is an autosomal dominant genetic disease involving the whole body system is the most common muscular dystrophy in adult,the main clinical manifestations in addition to muscle weakness,muscle atrophy and myotonia,often accompanied by multi-organ involvement including cataracts,cardiac arrhythmia,diabetes,alopecia,sweating,sexual dysfunction and mental deterioration.It can be divided into type DM1 and DM2 type according to different gene mutation.As to the clinical and pathological manifestations vary,DM is difficult to indentify with other myotonic myopathy and other muscular dystrophy in the early stage of the disease.However,with the development of molecular biology,we have a deeper understanding of DM,the study in molecular level which lays the foundation for definite diagnosis making the diagnosis enter a new era.In this study,we expect to improve the cognition and diagnosis level of DM,to reduce misdiagnosis rate and to guide treatment,prognosis and genetic counseling through a summary of clinical data and muscle pathology of DM affected and genes detection to dystrophia myotonica protein kinase(DMPK)gene in chromosome 19q13.3 and zinc finger protein 9(ZNF9)gene in chromosome 3q21.3 for definitive diagnosis of DM.Methods:In this study,data was from June 2007 to January 2016,Department of Neurology,the second hospital of Hebei medical university,in and out-patients,a total of 25 cases,which are in line with the clinical and pathological diagnostic criteria.We collected the clinical of each patient,including gender,age of onset,age of invistion,duration,family history,initial sysptom,sign,location and degree of muscle weakness,whether accompanied with muscle atrophy and muscle atrophy parts,“hathet face”,whether accompanied with multi-organ involvement,serum creatine kinase,EMG,ECG for in summary of clinical features.Muscle biopsies all were done for a complication of pathological features.And collected the same period of clinical,and routine staining,immunohistochemical of muscle pathology diagnosis for dysferlinopathy patients(DYSF group)and the patients pathological diagnosed of normal(CO group)were selected to serve as control samples,including 3,3 cases respectively.The group of 8 cases of patients(including 6 families)after informed consent were extracted from the peripheral blood for DMPK and ZNF9 gene detection to understand the molecular genetic characteristics.Comparing the proportion of internal nuclei fibers and miniFeret diameter between DM1 group that was definitely diagnosed with gene detection and CO group.The correlation between the repeat number of gene and age of onset,the degree of muscle pathological internal nuclei fibers involvement was analyzed.Results: 1 Clinical characteristics of patients with DM.In this study,data was from June 2007 to January 2016,Department of Neurology,the second hospital of Hebei medical university,in and out-patients,a total of 25 cases,which are in line with the clinical and pathological diagnostic criteria.In the 25 DM cases,which includes 14 males and 11 females,male and female incidence ratio is 1.27: 1,more common in men.The age of onset in DM varies from 9 to 52 years old,mean 26.96±11.95 years old,concentrating in the presence of 10-40 years.The 25 cases all are chronic processes,duration of 1-21 years,with a median duration of 8(11.5)years.In the 25 DM cases,the initial sysptom differs,manifesting as limb weakness accounted for 40%,lower extremity weakness in 20%,Making a fist with both hands can not immediately stretch by 20%,upper limbs weakness accounted for 12%;the initial symptoms hold back inflation and lower limbs trismus are rare.The order of the common signs with diagnostic value is decline of limb muscle strength,Making a fist with both hands can not immediately stretch,percussion myotonia,muscle atrophy;Only 7 cases with classical “hathet face”.The distal end of the limb muscle strength declination is more common than the proximal end.The order of muscle atrophy is followed by the distal upper extremity atrophy,masticatory muscle atrophy,lower limb atrophy,atrophy of the proximal upper limbs,shoulder muscle atrophy;sternocleidomastoid muscle atrophy and intercostal muscles atrophy are rare.There can still be seen the non-specific weakening or disappearance of tendon reflexes and tendon hyperreflexia in DM patients.DM patients in this group with other multi-system damage,including early alopecia,sexual dysfunction,heart damage,cataract and mental decline,etc.Laboratory examination showed the majority of patients with mild to moderate elevations of serum creatine kinase,median 304(315.25)IU /L.EMG showed myotonia potential in all DM patients,of which 60% with muscular damage,8% with neurogenic damage;2 Muscle pathology analysis of patients with DM.Under light microscope,HE staining revealed that connective tissue proliferation,muscle fibers arranged loosely in 22 DM patients.25 cases of DM patients with muscle fiber size is different,the visible atrophy of muscle fibers that were round or angular appearance,individual muscle fiber hypertrophy.It showed significant increase in the muscle membrane nucleus in 24 patients.Nuclear transfer in different degrees of muscle fibers were seen in 23 patients.There had nuclear bag formation in 23 cases.There had a different degree of muscle fiber necrosis or phagocytosis in 15 cases;13 patients with visible Circular fiber in muscle pathology;9 cases of patients with the presence of sarcoplasmic block in muscle fibers;5 cases seen with muscle fiber vacuolar degeneration;inflammatory cell infiltration rare.MGT staining could see ragged red fiber(RRF)in 4 cases.In 25 cases,NADH-TR and SDH staining showed that the oxidase distribution of the muscle fibers were uneven,which was like moth-eaten,and the edge of the fiber or partly atrophy muscle fibers was deeply stained.The muscle specimens of 19 cases showed some atrophic muscle fibers stained with NSE staining.9 cases showed increasing fat content in ORO staining.PAS staining showed slightly elevated glycogen ingredients in 7 cases.Mild to moderate increase of acid phosphatase activity was seen in 20 cases in ACP,which was stained in 23 patients.ATP staining showed muscle fiber have different degrees of atrophy in 25 cases of patients,including 17 cases with muscle fiber atrophy mainly involved in type I,7 cases with atrophy involving the two type,1 cases with atrophy involving type II;a total of 13 cases for myogenic grouping,which type I fibers dominant in 6 cases,type II fiber dominant in 7 cases.Immunohistochemical staining showed that Dystrophin-N/C/R,Dysferlin,Sacroglycan-?/?/?/? were normal in all of 5 cases;3 Pedigree analysis of gene detection.The group of 8 cases of patients(including 6 families)after informed consent were extracted from the peripheral blood for DMPK and ZNF9 gene detection.The results showed that 8 patients(including 6 families)were DMPK gene mutation,in which CTG repeat number was greater than 50,diagnosed as type DM1.There is two generation and generation above onset in four DM1 type families,with obvious genetic anticipation phenomena.Comparing with the first generation of patients,the second generation(all inherited from the mother)had in advance of 30.0±8.1 years;the number of repeated CTG was more than that of the first generation,with an average of 389.5±200.9.Among one case of the four family,the third generation patient(inherited from the father)whose repeat number of CTG was more than his father(the second generation patient)has no clinical symptoms now;4 Morphometric analysis of muscle pathology.Patients with type DM1 were significantly increased in the nuclear transfer of the patients with Dysferlinopathy.The type ? muscle fibers diameter significantly was smaller than the type ? muscle fibers in muscle pathology of DM1 patients;there are difference between the DM1 and control group,but not statistically significant.5 Genetic association analysis.The number of CTG repeat amplification in DM1 patients was negatively correlated with age of onset,and positively correlated with the proportion of internal nuclei fibers.Conclusions:1 DM is an autosomal dominant genetic myopathy,whose clinical manifestations are complex and diverse,in addition to myotonia,muscle weakness and atrophy in the most common,which often associates with other multi-system damage;The common signs of this disease are the decline of muscle strength,Making a fist with both hands can not immediately stretch,percussion myotonia and muscle atrophy.Therefore,we should increase the understanding of the disease,inquiry medical history detailed and physical examination to improve the clinical diagnosis rate of the disease and to reduce misdiagnosis.2 EMG is of great value in the diagnosis of DM,and the value of creatine kinase in the diagnosis of DM is not significant.3 The main muscle pathology features of DM are different muscle fibers size,nuclear transfer,nuclear bag formation,increase in the muscle membrane nucleus,myogenic grouping phenomenon and major involvement of type I muscle fiber atrophy.4 Genetic testing can confirm the diagnosis and classification in patients with DM;we found that the most common subtype was DM1 in the region.This type has obvious genetic anticipation phenomena,and the more repeated number of CTG,the earlier in the age of onset,the more severe in the degree of nuclear transferring in muscle pathology.Genetic testing is of great significance for DM1 clarifying diagnosis,guiding treatment,judging prognosis,providing genetic counseling,reducing the incidence of offspring and improving the quality of the population. |
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