Objective:To determine the clinical, pathological and imaging phenotypes of pediatric patients with anti-3-hydroxy-3-methylglutaryl-coenzyme A reductase (HMGCR) myopathy to explore its diagnostic strategies.Methods:The clinical features of 10 pediatric patients with anti-HMGCR myopathy in the Department of Neurology, Peking University First Hospital from July 2014 to July 2021 were collected. Muscle biopsies were performed in all patients, with histological, enzymatic histochemical and immunohistochemical staining.Results:The male to female ratio was 6∶4, the age of onset was 3-16 (8.3±3.7) years, 2 cases had subacute onset, and 8 cases experienced chronic progressive onset. All patients presented with neck and proximal muscular weakness of all limbs. Skin rash was observed in 2 cases. Serum creatine kinase was 998-27 981 U/L. The electromyography results were available from 6 cases, who experienced myogenic changes. The muscle magnetic resonance imaging was performed in 5 cases and revealed muscle edema predominantly in posterior compartment of thigh, with mild fatty infiltrate in 2 cases. An initial diagnosis was limb-girdle muscular dystrophy in 7 cases, but with subsequently negative genetic testing. Muscle biopsies revealed scattered necrotic fibers and regenerating fibers, complement deposition in sarcolemma basement-membrane areas of non-necrotic fibers and a few of lymphocyte infiltrate in all specimens. Moreover, a high frequency of major histocompatibility complex Ⅰ expression in muscle fibers was observed in 9 cases, proliferation of connective tissue of endomysium in 8 cases, muscle fiber hypertrophy in 4 cases and vacuoles in 2 cases.Conclusions:Pediatric anti-HMGCR myopathy is frequently misdiagnosed as muscular dystrophy. Systematic consideration of anti-HMGCR myopathy and testing for myositis specific antibody in children with genetically unconfirmed muscular dystrophy may help the differential diagnosis.

Objective:To summarize the clinical, pathological and muscle magnetic resonance imaging (MRI) features of human immunodeficiency virus (HIV)-associated nemaline myopathy (NM; HIV-NM).Methods:The present patient was a 23-year-old man with HIV infection who developed progressive proximal weakness and atrophy for more than 10 months. He was admitted to the Department of Neurology of Beijing Ditan Hospital in early June 2021. Electromyography showed myogenic findings. The serum creatine kinase was 202.4 U/L. CD 4+ count was 585×10 6/L. Serum monoclonal immunoglobulin (M protein) was negative. The patient underwent MRI examination of bilateral thigh muscles, biopsy of left biceps brachii and gene detection. The clinical, pathological and muscle MRI changes of HIV-NM were summarized based on the literature review. Results:MRI examination of bilateral thigh muscles showed edema changes. Muscle biopsy showed nemaline structures in some muscle fibers, accompanied by fiber atrophy and regeneration. No gene mutation related to clinical phenotype was found by second-generation sequencing. After intravenous immunoglobulin combined with prednisone, the patient′s weakness symptoms were significantly improved. A total of 17 cases of HIV-NM (including the present case) were identified in the literature, who were aged (33.7±9.1) years. Fifteen were males and two were females. All patients developed proximal limb weakness. Creatine kinase was normal or slightly elevated. Serum monoclonal protein was positive in 3 cases (3/7). Immunosuppressive therapy was effective.Conclusions:The main clinical characteristics of HIV-NM are progressive proximal limb weakness and muscle atrophy. The muscle pathology shows a large number of nemaline structures in atrophic muscle fibers. Muscle edema can be seen on muscle MRI. This is the first report of HIV-NM in China, which may be a special subtype of immune myopathy.

Objective:To summarize the characteristics of neuralgia in Fabry disease and explore the effects of genders and alpha-galactosidase A (GLA) gene mutation types on neuralgia.Methods:Questionnaires and Brief Pain Inventory evaluations were conducted on the recruited patients diagnosed as Fabry disease in Department of Neurology, Peking University First Hospital from January 2001 to April 2020. The characteristics of the neuralgia were summarized, and the portrait of neuralgia between male and female patients, and the patient groups carrying truncated mutations and non-truncated mutations of GLA gene was compared.Results:A total of 93 patients with Fabry disease were enrolled. The incidence of neuralgia was 91.4% (85/93),and the average onset age of pain was 9 years. The average remission age was 20 years with the remission incidence of 22.8% (18/79). Pain attack on extremities [96.5%(82/85)] was the most common form. The neuralgia relieving rate of male patients [17.5%(11/63)] was lower than that of females (7/16, χ2=5.01, P=0.025).Brief Pain Inventory scores showed that the degree of most severe pain attack within 24 hours of male patients (4.16±3.20) was higher than that of females (2.07±2.02, t=3.03, P=0.004),and the impact of pain on daily life [male 4 (7) vs female 0 (4), Z=-2.33, P=0.020], walking ability [male 5 (8) vs female 0 (2), Z=-2.87, P=0.004], daily work [male 5 (8) vs female 0 (2), Z=-3.10, P=0.002], relationship [male 2 (6) vs female 0 (3), Z=-2.67, P=0.008] and interests [male 4 (8) vs female 0 (3), Z=-2.81, P=0.005] of male patients was also higher than female patients. The truncated mutation group [1 (2)] only showed higher score on the current pain level than the non-truncated mutation group [0(0), Z=-2.89, P=0.003]. Conclusions:The neuralgia in Chinese patients with Fabry disease showed high incidence and early onset. Male patients presented more severe pain than female which led to a greater impact on life, while the type of GLA gene mutation had less impact on neuralgia.

The vacuole in muscle fibers is a non-specific myopathological change. As a myopathological term, it occurs in several rare disorders. The vacuoles are mostly related to the autophagy of glycogen, lipids, abnormal proteins, and organelles, and a few are caused by glycogen or lipids deposition or sarcoplasmic reticulum luminal vacuolization. The vacuoles impair the structure of muscle fibers, being one of the myopathological features in various diseases. In this review, clinical features and myopathological changes of various diseases with vacuolar muscle fibers were introduced and the diagnostic value of intrafibral vacuoles was focused on. Knowing the underlying pathogenesis is required to understand these myopathological changes.

Objective:To summarize and analyze the clinical data of Chinese patients with colony-stimulating factor 1 receptor (CSF1R)-related leukoencephalopathy, and clarify the phenotypic and genetic characteristics of Chinese patients.Methods:Medical history of patients with CSF1R-related leukoencephalopathy diagnosed from April 1, 2018 to January 31, 2021 in the department of neurology of 22 hospitals in China was collected, and scores of Mini-Mental State Examination (MMSE), Montreal Cognitive Assessment Scale (MoCA), magnetic resonance severity scale were evaluated. Group comparison was performed between male and female patients.Results:A total of 62 patients were included, and the male-female ratio was 1∶1.95. The age of onset was (40.35±8.42) years. Cognitive impairment (82.3%, 51/62) and motor symptoms (77.4%,48/62) were the most common symptoms. The MMSE and MoCA scores were 18.79±7.16 and 13.96±7.23, respectively, and the scores of two scales in male patients (22.06±5.31 and 18.08±5.60) were significantly higher than those in females (15.53±7.41 , t=2.954, P=0.006; 10.15±6.26, t=3.328 , P=0.003). The most common radiographic feature was bilateral asymmetric white matter changes (100.0%), and the magnetic resonance imaging severity scale score was 27.42±11.40, while the white matter lesion score of females (22.94±8.39) was significantly higher than that of males (17.62±8.74 , t=-2.221, P<0.05). A total of 36 CSF1R gene mutations were found in this study, among which c.2381T>C/p.I794T was the hotspot mutation that carried by 17.9% (10/56) of the probands. Conclusions:The core phenotypic characteristics of CSF1R-related leukoencephalopathy in China are progressive motor and cognitive impairment, with bilateral asymmetrical white matter changes. In addition, there exist gender differences clinically, with severer cognitive impairment and imaging changes in female patients. Thirty-six CSF1R gene mutations were found in this study, and c.2381T>C/p. I794T was the hotspot mutation.

目的 探讨老年慢性阻塞性肺疾病急性加重期(acute exacerbation of chronic obstructive pulmo-nary disease,AECOPD)患者血清超敏C反应蛋白(hs-CRP)、补体C1q/肿瘤坏死因子相关蛋白-9(CTRP-9)和甲壳质酶蛋白-40(YKL-40)水平变化及临床意义.方法 选取157例老年慢性阻塞性肺疾病(chronic ob-structive pulmonary disease,COPD),其中AECOPD 63例作为AECOPD组,稳定期COPD 94例作为稳定期COPD组;另选取同期健康体检者50例作为对照组.比较3组血清hs-CRP、CTRP-9、YKL-40水平和肺功能指标,采用Pearson相关性分析探讨血清hs-CRP、CTRP-9和YKL-40水平与COPD患者肺功能指标相关性,应用受试者工作特征(ROC)曲线分析血清hs-CRP、CTRP-9和YKL-40对AECOPD患者诊断价值.结果 3组血清hs-CRP、CTRP-9、YKL-40水平和肺功能指标总体比较差异有统计学意义(P<0.01).与对照组比较,AECOPD组和稳定期COPD组血清hs-CRP、CTRP-9和YKL-40水平均升高,第1秒用力呼气容积占预计值百分比(FEV1％)和第1秒用力呼气容积与用力肺活量比值(FEV1/FVC)均降低,差异有统计学意义(P<0.01);与稳定期COPD组比较,AECOPD组血清hs-CRP、CTRP-9和YKL-40水平升高,FEV1％和FEV1/FVC降低,差异有统计学意义(P<0.01).Pearson相关性分析结果 显示,COPD患者血清hs-CRP、CTRP-9和YKL-40水平与FEV1％及FEV1/FVC呈负相关(P<0.01).ROC曲线分析结果 显示,血清hs-CRP、CTRP-9和YKL-40诊断AECOPD的最佳截断值分别为10.54 mg/L、148.58 ng/ml和46.23 ng/ml,此时诊断AECOPD具有较高的敏感度与特异度,且血清CTRP-9和YKL-40诊断AECOPD的曲线下面积高于血清hs-CRP.结论 老年COPD患者血清hs-CRP、CTRP-9和YKL-40水平升高,且与肺功能指标密切相关;血清hs-CRP、CTRP-9和YKL-40可作为诊断AECOPD的标志物,且血清CTRP-9和YKL-40诊断AECOPD的价值高于血清hs-CRP.

Objective To report the clinical features,myopathological changes,and gene mutations in five Chinese patients with mitochondrial diseases caused by POLG gene mutations. Methods Clinical materials of five unrelated patients who were treated in Department of Neurology,Peking University First Hospital from April 2012 to January 2018,carrying POLG gene mutations,were retrospectively analyzed. Muscle/nerve biopsies and targeted

A 58-year-old man who presented with progressive proximal weakness and elevated serum creatine kinase levels was found to have typeⅢa glycogen storage disease. Except for a history of later motor milestone in childhood, he was healthy and lived a normal life. There was no hypoglycemia, hepatomegaly or growth retardation. Muscle weakness was not apparent until the fourth decade. Scoliosis and mild hypertrophy of cardiac ventricular septum were detected. Muscle biopsy was performed which revealed amount of glycogen depositing. A novel homogenous splicing mutation was found in AGL gene.

Objective To report the clinical and peripheral neuropathological findings in two patients with autosomal recessive Charcot-Marie-Tooth disease 2K(AR-CMT2K).Methods Case one was a nine year-old girl.She had distal weakness of lower limbs for six years, with calf atrophy and contracture of Achilles tendon for three years.Case two was an eight year-old boy.He had distal weakness of lower limbs with contracture of Achilles tendon and calf muscle atrophy for three years, and proximal weakness of low limbs for two years.The motor nerve conduction velocities in median nerves were 48.1 m/s in case one and 47.6 m/s in case two.The compound motor action potential amplitude of median nerves decreased by 46% in case one and 69% in case two.Sural nerve biopsies and gene targeted next-generation sequencing were performed in both patients.Results Density of myelinated fibers was 8 407/mm2 in case one and 7 714/mm2 in case two.The ratio of myelinated fibers with diameter over 8 μm was 2.6% in case one and 0 in case two.Both patients had small regenerating cluster of myelinated fibers.Thin myelinated fibers appeared in case one.In case two, atypical onion bulb formations with focal folded myelin appeared, and electromicroscopy revealed mitochondrial aggregate in axons.Compound heterozygous mutations of ganglioside-induced differentiation associated protein 1 gene were detected in both patients, including c.767A>G(p.H256R) and c.466G>A (p.A156T) in case one and c.767A>G and 845G>A(p.R282H) in case two.Conclusions Contracture of Achilles tendon may appear in early childhood of AR-CMT2K patients.The main pathological changes in sural nerve are loss of large myelinated fibers, mitochondrial aggregate in axons and myelin abnormalities.

Objective To summary the pathological and genetic features in nine Chinese limb girdle muscular dystrophy 2I (LGMD2I) patients.Methods Nine LGMD2I patients were recruited from Peking University First Hospital between 2011 and 2016, who came from nine unrelated and non-consanguineous families.The mean age of onset was (8.2±5.2) years (2 to 19 years), and the mean disease duration was (10.4±6.1) years (1 to 24 years).There were six males and three females, present with weakness in limb girdle muscles, four of whom accompanied with calf hypertrophy and three with scapular winging.Serum creatine kinase was 964-23 131 U/L (normal 25-190 U/L).Five of them who conducted electromyogram showed myogenic pattern.Muscle biopsy and next generation sequencing were performed in these patients, then sanger sequencing was performed to determine whether the variants co-segregated with the phenotype in these families.Results Muscle biopsy revealed myopathy features in six patients, dystrophic change in one, and only mild changes in two.Major histocompatibility complex-Ⅰ was positive in six cases, and rimmed vacuoles were found in two.There were seven mutations in fukutin-related protein (FKRP) gene.A reported mutation of c.545A>G (p.Y182C) appeared in eight cases, including three homozygotes and five compound heterozygotes.The mutation of c.1067T>C (p.Ile356Thr) was reported too.And c.1263C>A (p.Tyr421X), c.534G>T(p.Thr178Cys), c.1027G>C (p.Glu343Gln), c.1027G>T(p.Glu343X), c.1448A>G (p.Tyr483Cys) were found to be novel mutations.Conclusions LGMD2I showed large variation in myopathology.The missense mutation A545G(Y182C) is a hot spot of FKRP gene in our series.

病历摘要 患者女性,52岁,汉族,因"进行性四肢无力4年,活动后胸闷2年"于2015年4月22日就诊于我院.患者4年前无明显诱因出现走路姿势异常,呈"外八字"状,自觉右下肢无力,但仍可独立上下楼.3年前出现双下肢无力,走平路20~30 min即需要休息,休息后略好转,蹲起和上下楼均困难.2年3个月前出现双上肢上举困难,梳头费力,但夹菜和抓物动作正常.2年前四肢无力进一步加重,同时间断出现活动后胸闷、心慌和心前区不适感,持续数分钟至数十分钟不等,可自行缓解,不伴随心前区疼痛,遂就诊于心血管科.行心电图检查正常,肌酸激酶及肌酸激酶同工酶均升高,经神经科检查发现右下肢肌肉萎缩.

Objective To investigate the pathological features of chronic idiopathic axonal polyneuropathy ,and the expression of endothelial-nitricoxide synthase and thrombomodulin in the endothelium of the vascular in sural nerve in pa -tients with CIAP.Methods We collected 10 patients with CIAP confirmed by clinical and electrophysiological examination and nerve pathologydiagnosis .Sural nerve biopsies were performed in all of them .We did the routine histological staining and Envision immunohistochemical staining with first antibodies against inflammatory cell markers of CD3 ,CD 20 ,CD68 and endothelial cell markers of eNOS ,TM and vWF.Results Sural nerve biopsies showed mild to moderate loss of myelinated fibers with axonal degeneration and regeneration .A few of them showed slight demyelination of myelinated fibers and thick basal membrane of capillary .4 patients had CD68-positive mononuclear cells within the fascicular .No CD3 and CD20-pos-itive lymphocytes were found .All of the patients had positive expression with eNOS ,TM,vWF in the endothelial cells of the blood vessels .Conclusion The main pathological features were axonal damage .The pathogenesis of CIAP might relate to humoral immunological abnormalities .Thick basal membrane of capillary in some patients indicated the vascular endothelial cell functions injured ,but the expression of vascular endothelial cell functional proteins was normal .

Objective To explore the clinical,electrophysiological and pathological features in 4 cases of chronic inflammatory demyelinating polyneuropathy with GM1-IgM antibodies.

Objective To summarize clinical phenotypes and pathological characteristics in myopathies with tubular aggregates (TAs).Methods We reviewed 5 697 patients who performed muscle biopsies in our department between January 2001 and July 2015.We collected the cases with TAs and made classification based on their clinical diagnoses and pathological changes.Results Fifty-seven patients (1.00％) showed TAs in muscle specimens,including 50 (87.72％) males and 7 (12.28％) females.According to clinical,neurophysiological,pathological and genetic analysis,the diagnoses included 23 (40.35％) cases of periodic paralysis,7 (12.28％) cases of chronic alcohol intoxication,6 (10.53％) cases of congenital myasthenic syndrome,5 (8.77％) cases of exercise-induced cramps,3 (5.26％) cases of necrotizing myopathy,1 (1.75％) case of stromal interaction molecule 1-associated myopathy,limbgirdle muscular dystrophy 2E,myotonic dystrophy,myotonia congenita,paramyotonia congenitia,hypothyroid myopathy respectively.Other cases of unknown cause included unclassified distal myopathy,external ophthalmoplegia,white matter lesions,mental retardation,stroke,early onset weakness,pulmonary arterial hypertension.Besides TAs,pathological changes also included necrosis of muscle fibers (3 cases,5.26％),neurogenic changes (3 cases,5.26％) and muscular dystrophic changes (1 case,1.75％).Conclusions Our results indicated that TAs are usually found in males and could present in many types of hereditary or acquired neuromuscular disease as independent or accompanying changes.Periodic paralysis,chronic alcohol intoxication and congenital myasthenic syndrome are 3 major diseases causing myopathies with TAs.

OBJECTIVE To report the clinical and myopathological features of 16 patients with Jo-1 syndrome. METHODS Sixteen patients were recruited in this study, who were diagnosed as Jo-1 syndrome in Department of Neurology of Peking University First Hospital from January, 2011 to July, 2015. The clinical data and myopathological data were analyzed. RESULTS The mean onset age was 41±14 (21-68) years old. 87.5% was female. The median duration was 9.5 months (1-192 months). The main clinical manifestations were weakness in 13 cases (81.2%), arthritis in 10 cases (62.5%), interstitial lung diseases in 8 cases (50%), dermatomyositis-like skin lesions in 5 cases (31.2%), fever in 3 cases (18.8%), Raynaud's phenomenon in 2 cases (12.5%) and mechanic's hands in 2 cases (12.5%). There were 3 cases with other connective tissue diseases and 1 case with non-Hodgkin's lymphoma. Mean serum CK was 3 054±2 058(470-5 222) U/L. All patients had anti-Jo-1antibody, combined with anti- Mi-2 antibody in 1 case, anti-Ro-52 antibody in 5 cases, and anti-nuclear antibody in 5 cases. 4/5 cases showed myopathic changes for electromyography (EMG) tests. Myopathological changes included edema, fragmentation and inflammatory infiltration in perimysium in 14 cases (87.5%), muscle atrophy in 13 cases including 7 cases(43.8%) predominantly in perifascicular field. Muscle fiber necrosis appeared in 8 cases with predominantly in perifascicular area in 4 cases (25%). Muscle fiber regeneration occurred in 11 cases with predominantly in perifascicular field in 5 cases (31.2%). CD8 positive T-lymphocytes, CD20 positive B-lymphocytes and CD68 positive macrophages infiltrated in various degrees, most of which were located in perimysium. MHC-Ⅰ were expressed on muscle fiber membranes in different degrees, including 7 cases (43.8%) predominantly in the cytoplasm of perifascicular muscle fibers. C5b-9 deposited in perifascicular muscle fiber membranes in 7 cases (43.8%) and perifascicular capillaries in 2 cases (12.5%). CONCLUSIONS The main manifestations of this group of Jo-1 syndrome are weakness, arthritis and interstitial lung diseases, and dermatomyositis-like skin lesions, fever, Raynaud's phenomenon, and mechanic's hands can also be seen. Edema, fragmentation and inflammatory infiltration in perimysium are common. Pathological changes in perifascicular fields appear in some cases.

Neuromuscular diseases refer to a group of diseases mainly involving peripheral nerve, neuromuscular junction (NMJ) and muscle. Except for the traditional clinical diagnosis, such as serological tests, neuroelectrophysiological study and pathological diagnosis, multilevel detection technologies, including clinical, neuroimaging study, cell and molecular biology, are widely used in the diagnosis of neuromuscular diseases. It is necessary to realize the standardization and systematization of the management of clinical and biological resources in the study of neuromuscular diseases. This paper reviews the establishment, management and application of clinical biobanks, so as to promote the research of neuromuscular diseases. DOI: 10.3969/j.issn.1672-6731.2016.10.003

Objective To report the reversible postictal cranial MRI changes in two epileptic patients and to discuss the pathogenesis of the lesions. Methods The first 28 years old male patient suffered from a generalized seizure secondary to the partialized attack after fever and headache 8. 5 year ago. The second female patient, 20 years old, complained about episodes of generalized seizure for 9 years, psychomotor seizure for 7. 5 years. The seizures stopped after antiepileptic drug treat-ment in both patients and the diagnosis of secondary epilepsy was ruled out based on the thorough physical examinations and laboratory tests. We evaluated the first patient’s MRI on the third day, 1st and 3rd month after seizure. We also reviewed the second patient’s MRI which was performed 1 week, 1. 5 years, 2 and 3 years respectively after the first attack. Results The first patient was re-vealed multiple, long T1, long T2 signals in the cortical and subcortical areas of bilateral frontal lobes and right occipital lobe on 3rd day after the attack. The MRI lesions were found to elapse both in size and number in the following three months. In the second patient, cranial MRI showed long T2 signal in the right temporal lobe 1. 5 years after the first attack. The further MRI inspections were un-revealing. Conclusion The reversible intracranial lesions could appear in epileptic patients after once or more attacks. These lesions, whether single or multiple, tend to locate in the area of frontal, occipital and temporal lobe. The dynamic MRI inspection can help to diagnose and avoid unnecessa-ry examinations.

目的 探讨以神经束衣炎为首发表现的肺非朗格汉斯细胞组织细胞增生症的临床特点.方法 回顾性分析1例以神经束衣炎为首发表现的肺非朗格汉斯细胞组织细胞增生症患者的临床资料.结果 患者为36岁男性,出现多发性单神经炎以及多发性周围神经病,同时出现严重的肺部病变.抗神经节苷酯2(GM2) IgM抗体增高.神经传导速度证实存在广泛感觉、运动神经病.血清GM2 IgM抗体显著升高.对此患者进行神经活检以及肺组织活检.腓肠神经活检证实显著的神经束衣炎伴随大量神经纤维丢失.肺组织活检为非郎格汉斯组织细胞增生症.结论 本病例首次证实神经束衣炎可以出现在肺非郎格汉斯组织细胞增生症,运动、感觉神经均可受累.GM2 IgM抗体可能参与疾病的发生.

目的 总结几种常见类型先天性肌病大腿肌肉MRI的改变规律,评价其诊断价值.方法 选取通过肌肉病理检查确诊的先天性肌肉病患者12例,包括杆状体肌病5例、轴空病4例、中央核肌病3例,其中男性9例,女性3例,平均年龄(19.6±10.1)岁,平均病程(14.1±11.7)年,3例患者家系内有类似发病者.所有患者行大腿骨骼肌MRI检查,行T1WI序列观察骨骼肌脂肪化,行STIR序列观察骨骼肌水肿情况,对大腿12块肌肉脂肪化和水肿程度进行6级评分.结果 先天性肌病患者大腿不同肌肉脂肪化评分平均在(1.75±1.09)分到(3.67±0.85)分之间,大腿肌肉平均脂肪化总分分别为中央核肌病(41.00±11.34)分,多发微小轴空病(31.25±4.32)分,杆状体肌病(22.8±3.71)分,且不同类型先天性肌病肌肉脂肪化分布形式存在差异.9例出现大腿肌肉萎缩,其中5例为弥漫性萎缩,4例为后群及内侧群肌肉萎缩.所有患者均不存在肌肉肥大.3例皮下筋膜水肿,1例股四头肌水肿.结论 不同类型先天性肌病脂肪化及萎缩程度存在明显差异.大腿肌肉无肥大是其共同特点.

Objective To investigate the clinical and genetic characteristics of a cohort of Chinese patients with large-scale single deletion in mitochondrial DNA (mtDNA).Methods Long-range PCR was performed to search large scale deletions in 70 patients' muscle mtDNA who were diagnosed with mitochondrial disease by clinical and muscle pathological examination.Then multiple restriction enzyme digestion of long-range PCR product followed by short-cycle PCR were used to define the exact size and location of large-scale deletions.We summarized the clinical phenotypes of patients,and analyzed the correlations between clinical phenotypes and size of mtDNA deletions in those patients with single large-scale deletion.Results Sixty-one patients were identified to have single large-scale deletion in their muscle mtDNA,including 54 patients with chronic progressive external ophthalmoplegia (CPEO),6 with KearnsSayre syndrome (KSS) and 1 with mitochondrial myopathy,encephalopathy,lactic acidosis and stroke-like episodes.Totally 37 patterns of mtDNA deletions were detected in this cohort of patients.The "common deletion",4 977 bp deletion appeared in 39.3％ (24/61) patients.The mean size of single deletion in CPEO patients was (5 052.17 ± 1 390.96) bp,while in KSS patients it was (5 912.43 ± 1 262.15) bp.There was no significant difference between CPEO patients group and KSS patients group.The size of deletions was correlated with onset age (r =-0.415,P =0.001).Conclusions Large-scale single deletion of mtDNA mainly causes CPEO and KSS.Patients with larger deletions present with earlier onset of disease.The mtDNA "common deletion" is also common in Chinese patients.