| BackgroundMitochondrial disease is a group of clinically and geneticaly heterogeneous disorders driven by oxidative phosphorylation dysfunction of the mitochondrial respiratory chain due to pathogenic mutations of mitochondrial DNA or nuclear DNA.The clinical manifestations of mitochondrial disease are complex and changeable,which can easily lead to misdiagnosis and missed diagnosis,besides,the prognosis of the disease is poor.Therefore,early diagnosis and early treatment are particularly important.ObjectiveThe purpose of our study was to retrospectively analyze the general data,clinical symptoms,and the results of laboratory tests,electrophysiologic examination,neuroimaging,muscle biopsy and gene test in those who were diagnosed with mitochondrial disease in our hospital,and thus,provide a reference for early diagnosis and early treatment.MethodsWe retrospectively analyzed the clinical data of 51 patients who were diagnosed with mitochondrial diseases from June 2016 to January 2021 in the Department of Neurology,Nanfang Hospital,Southern Medical University.All the patients were confirmed by muscle biopsy and/or gene test.The general information of the patients as well as the frequency of the initial symptoms,major neurological symptoms and non-neurological symptoms were counted.The results of serum and cerebrospinal fluid test,electrophysiology,neuroimaging,muscle biopsy,and gene test were collected.51 patients who were eligible as per the inclusion and exclusion criteria were enrolled.(1)Inclusion criteria:Patients with typical clinical manifestations of mitochondrial diseases and supported by muscle pathology and/or genetic test;(2)Exclusion criteria:①Patients were excluded by muscle pathology and genetic test;②Diagnose as other diseases,i.e.,inflammation,infection,tumor,ischemia,hypoxia,poisoning,and other genetic metabolic diseases.Results1.Clinical feature:Patients with mitochondrial diseases in our center have a wide range of onset ages from 0 to 65 years old,commonly affecting young and middle-aged patients,with a male-female ratio of 1.55:1.Mitochondrial disease is a clinically heterogeneous disorder.The sequence according to the frequency of main symptoms is as follows:stroke-like episodes,epileptic seizure,limb weakness,headache,vision loss,exercise intolerance,fever and hearing loss.2.Neuroimaging:The MRI of the patients showed low signal on T1WI,high signal on T2WI and FLAIR,high signal or slightly high signal on DWI and ADC.The lesions were mainly distributed in the cortex,and most of them involved two or more cerebral lobes which are mainly in the occipital,temporal and parietal lobes.MRS showed increased choline peak,decreased NAA peak and high lactic acid peak in the region-of-interest.3.Muscle pathology:Among the 51 patients,38 had completed muscle biopsy,among which,ragged-red fibers,strongly SDH reactive blood vessels and COX-negative muscle fibers are the most typical muscle pathological features of mitochondrial diseases.In a single biopsy specimen,the manifestations mentioned above could appear simultaneously or exist in different combinations.4.Genetic test:Genetic analysis was performed in 46 of the 51 patients.m.3243 A>G is the most common mutation of mitochondrial diseases in our center,accounting for 45.65%(21/46).In addition,m.7811A>G,m.5825C>T,c.41A>G,c.286C>T,and c.394C>T are five novel mutations in our study,however its pathogenicity should be further verified.Conclusions1.Mitochondrial disease is a clinically heterogeneous disorder with a wide range of the onset ages,most commonly in young and middle ages.The male to female ratio is 1.55:1.2.The clinical manifestation and routine laboratory examination are regarded merely as reference for the diagnosis of mitochondrial disease.The final diagnosis of mitochondrial disease requires the support of muscle pathology and gene test.3.The most common mutation site of mitochondrial disease in our center is m.3243A>G.In addition,m.7811A>G,m.5825C>T,c.41A>G,c.286C>T,c.394C>T are the novel mutations but need further investigate. |
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