基于多回波M-Dixon quant技术和T 2-mapping技术鉴别抗肌萎缩蛋白病分型的研究

目的:本研究探讨MRI多回波M-Dixon quant技术和T 2-mapping技术鉴别抗肌萎缩蛋白病分型的应用价值。方法:纳入抗肌萎缩蛋白病患儿共75例,其中杜氏肌营养不良(DMD)50例,贝氏肌营养不良症(BMD)25例。所有受试对象均进行大腿肌肉T 1WI-Dixon、多回波M-Dixon quant和T 2-mapping成像,并测量右侧大腿14块肌肉(臀大肌、阔筋膜张肌、股外侧肌、股中间肌、股内侧肌、股直肌、缝匠肌、长收肌、大收肌、股薄肌、半膜肌、半腱肌、股二头肌长头、股二头肌短头)的FF值、T2值。采用两独立样本比较的Mann-Whitney U检验比较DMD组和BMD组各肌肉FF值、T2值及14块肌肉平均FF值、T2值的差异,并绘制14块肌肉平均FF值、T2值的受试者工作特征(ROC)曲线,计算曲线下面积(AUC),分别评估曲线对DMD和BMD的鉴别诊断效能。结果:①DMD组以臀大肌FF值最高,其次是大收肌、股四头肌,以股薄肌、缝匠肌及长收肌最低;BMD组以臀大肌FF值最高,其次是股内侧肌,以股薄肌、长收肌最低。②DMD组以臀大肌T2值最高,其次是大收肌、股四头肌,以股薄肌、半腱肌最低;BMD组以臀大肌T2值最高,其次是股内侧肌,以股薄肌、半腱肌最低。③除缝匠肌及长收肌以外(P>0.05),DMD组其余12块肌肉FF值、14块肌肉平均FF值均高于BMD组,差异具有统计学意义(P<0.05)。DMD组各肌肉T2值及14块肌肉平均T2值均高于BMD组,差异具有统计学意义(P<0.05)。14块肌肉平均FF值、T2值鉴别DMD组与BMD组的AUC分别为0.709(0.591~0.828)、0.924(0.857~0.992),以14块肌肉平均T2值的鉴别二者效能最高,最佳临界值为41.55 ms,灵敏度86%,特异度88%。结论:多回波M-Dixon quant技术和T 2-mapping技术均可高效的鉴别抗肌萎缩蛋白病患儿,基于T 2-mapping技术的肌肉T2值测量具有更高的诊断效能,具有一定的临床意义。

M-Dixon quant和T2-mapping对杜氏肌营养不良症患儿进展前期及进展期运动功能的评估

目的探讨M-Dixon quant和T2-mapping技术评估杜氏肌营养不良症(DMD)患儿进展前期及进展期运动功能的价值,为精确评估DMD病情和监测随访提供合适的影像学工具。方法前瞻性收集40例经基因检测或组织病理活检确诊的DMD男性患儿,进展前期(<7岁)患儿20例,进展期(≥7岁)患儿20例。所有患儿均进行下肢M-Dixon quant和T2-mapping检查,观察进展前期及进展期患儿大腿肌肉的MRI表现,选取右侧大腿14块肌肉并测量其脂肪分数(FF)值和T2值。根据运动功能量表(MFM)评分对患儿进行运动功能评估并计算MFM总评分。采用Pearson相关分析2组患儿各肌肉FF值、T2值与MFM总评分的相关性(rFF,rT2)。结果进展前期DMD患儿大腿肌肉MRI表现为轻微脂肪浸润,随疾病进展表现为脂肪浸润程度加重。进展前期DMD患儿臀大肌、半膜肌、半腱肌FF值与MFM总评分均呈负相关(均P<0.05);除大收肌外,其余13块肌肉T2值与MFM总评分均呈负相关(均P<0.05),以股中间肌与MFM总评分的相关性最强。进展期DMD患儿14块肌肉FF值、T2值与MFM总评分均呈负相关(rFF为-0.877~-0.697,rT2为-0.968~-0.774,均P<0.05),以股外侧肌相关性最强。进展期DMD患儿每块肌肉的rT2均高于rFF。结论DMD患儿大腿肌肉受累有一定的进展规律。无论是进展前期还是进展期,相对于M-Dixon quant技术,T2-mapping技术能够更准确地反映疾病严重程度,疾病进展前期患儿的股中间肌和进展期患儿的股外侧肌T2值可作为评估DMD病情的良好指标。

Cardiac involvement in Duchenne and Becker muscular dystrophy

Duchenne and Becker muscular dystrophy(DMD/BMD) are X-linked muscular diseases responsible for over 80% of all muscular dystrophies. Cardiac disease is a common manifestation,not necessarily related to the degree of skeletal myopathy; it may be the predominant manifestation with or without any other evidence of muscular disease. Death is usually due to ventricular dysfunction,heart block or malignant arrhythmias. Not only DMD/BMD patients,but also female carriers may present cardiac involvement. Clinically overt heart failure in dystrophinopathies may be delayed or absent,due to relative physical inactivity. The commonest electrocardiographic findings include conduction defects,arrhythmias(supraventricular or ventricular),hypertrophy and evidence of myocardial necrosis. Echocardiography can assess a marked variability of left ventricular dysfunction,independently of age of onset or mutation groups. Cardiovascular magnetic resonance(CMR) has documented a pattern of epicardial fibrosis in both dystrophinopathies' patients and carriers that can be observed even if overt muscular disease is absent. Recently,new CMR techniques,such as postcontrast myocardial T1 mapping,have been used in Duchenne muscular dystrophy to detect diffuse myocardial fibrosis. A combined approach using clinical assessment and CMR evaluation may motivate early cardioprotective treatment in both patients and asymptomatic carriers and delay the development of serious cardiac complications.

Adipose-derived stem cells enhance myogenic differentiation in the mdx mouse model of muscular dystrophy via paracrine signaling

Adipose-derived stem cells have been shown to promote peripheral nerve regeneration through the paracrine secretion of neurotrophic factors. However, it is unclear whether these cells can promote myogenic differentiation in muscular dystrophy. Adipose-derived stem cells （6 × 106） were injected into the gastrocnemius muscle of mdx mice at various sites. Dystrophin expression was found in the muscle fibers. Phosphorylation levels of Akt, mammalian target of rapamycin （mTOR）, eIF-4E binding protein 1 and $6 kinase 1 were increased, and the Akt/mTOR pathway was activated. Simultaneously, myogenin levels were increased, whereas cleaved caspase 3 and vimentin levels were decreased. Necrosis and fibrosis were reduced in the muscle fibers. These findings suggest that adipose-derived stem cells promote the re- generation and survival of muscle cells by inhibiting apoptosis and fibrosis, thereby alleviating muscle damage in muscular dystrophy.

Cardiomyopathy in becker muscular dystrophy:Overview

Becker muscular dystrophy(BMD) is an X-linked recessive disorder involving mutations of the dystrophin gene. Cardiac involvement in BMD has been described and cardiomyopathy represents the number one cause of death in these patients. In this paper, the pathophysiology, clinical evaluations and management of cardiomyopathy in patients with BMD will be discussed.

Recurrent hypotension induced by sacubitril/valsartan in cardiomyopathy secondary to Duchenne muscular dystrophy: A case report

BACKGROUND Duchenne muscular dystrophy(DMD),which is caused by a mutation/deletion in the dystrophin gene on the X-chromosome,is the most common type of neuromuscular disorder in pediatrics.Skeletal muscle weakness progressively develops in DMD patients and usually leads to respiratory failure in the early adolescent years.Cardiac muscle is frequently affected in DMD patients,which leads to a high burden of cardiomyopathy and heart failure.In the era of improved respiratory care,cardiac deaths are becoming the major cause of mortality in DMD patients.CASE SUMMARY We report the case of a 15-year-old boy who presented to the hospital due to recurrent orthopnea for 6 mo and palpitations for 4 mo.He was diagnosed with progressive muscular dystrophy at the age of 3 years and was confined to a wheelchair at 12 years.He was prescribed diuretics and digoxin at the outpatient clinic;however,his symptoms did not resolve.Sacubitril/valsartan was added 1 mo prior to presentation,but he experienced recurrent episodes of palpitations.The electrocardiogram showed atrial tachycardia with a heart rate of 201 bpm,and he was then hospitalized.Hypotension was found following the administration of sacubitril/valsartan tablets;he could not tolerate even a small dose,always developing tachyarrhythmia.His symptoms were relieved after discontinuing sacubitril/valsartan,and his heart rate was controlled by a small dose of metoprolol tartrate and digoxin.Atrial tachycardia spontaneously converted in this patient,and his symptoms attenuated in the following 6 mo,without palpitation episodes.CONCLUSION Blood pressure should be closely monitored in DMD patients with advanced heart failure when taking sacubitril/valsartan.

A NEW APPROACH TO GENE DIAGNOSIS OF DUCHENNE/BECKER MUSCULAR DYSTROPHY──AMPLIFIED FRAGMENT LENGTH POLYMORPHISM

Four (CA)n repeats, located in introns 44, 45, 49 and 50 of the dystrophin gene., were evaluated in Chinese. These loci are highly polymorphic, with polymorphism information contents of 0. 872, 0. 772, 0. 870 and 0. 718, respectively. All four loci can be easily amplified and labelled using two duplex PCR reactions with α-32P-dCTP and can be detected by denaturing polyacrylamide gel electrophoresis. Using these four loci and the two polymorphic (CA)n repeats located at the 5' and 3' ends of the dystrophin gene, we have developed a new PCR-based procedure -Amp-FLP (amplified fragment length polymorphism) linkage analysis for the gene diagnosis of DMD/BMD. This method can detect intragenic recombination rapidly and efficiently and greatly. improves the success rate of carrier detection and prenatal diagnosis in non-deletion DMD/BMD families. All of the loci used in this procedure are intragenic. In addition, the loci in introns 44. 45, 49 and 50 are located in the deletion-prone region of the dystrophin gene, making them valuable and useful in the identification of deletion mutations. Here we report one case of deletion detection using these four loci.

Obesity and pericallosal lipoma in X-linked emery-dreifuss muscular dystrophy:A case report-Does Emerin play a role in adipocyte differentiation?

Emery dreifuss muscular dystrophy(EDMD) is a rare genetic syndrome consisting of tendon retractions,progressive muscle atrophy and cardiac involvement.We report a case of an obese patient affected by the familial X-linked form in which a pericallosal lipoma was found during investigation for a suspected acute vasculopathy.To date,EDMD has never been associated with cerebral lipomas and the X-linked form was never considered to be involved in lipodystrophic syndromes or non-muscular conditions.Our case confirms the variable expressivity of the disease and suggests a possible role of Emerin in the intranuclear regulation of signals for adipocyte cell differentiation.

Surgical and long-term functional outcomes of patients with Duchenne muscular dystrophy following spinal deformity correction

BACKGROUND Life expectancy in patients with Duchenne muscular dystrophy(DMD)has improved due to advances in medical care.DMD patients develop progressive spinal deformity after loss of ambulatory function and onset of wheelchair dependence for mobility.There is limited published data on the effect of spinal deformity correction on long-term functional outcomes,quality of life(QoL),and satisfaction in DMD patients.AIM To investigate the long-term functional outcomes following spinal deformity correction in DMD patients.METHODS This was a retrospective cohort study from 2000-2022.Data was collected from hospital records and radiographs.At follow-up,patients completed the muscular dystrophy spine questionnaire(MDSQ).Statistical analysis was performed by linear regression analysis and ANOVA to analyse clinical and radiographic factors significantly associated with MDSQ scores.RESULTS Forty-three patients were included with mean age 14.4 years at surgery.Spinopelvic fusion was performed in 41.9%of patients.Mean surgical time was 352.1 min and mean blood loss was 36%of estimated total blood volume.Mean hospital stay was 14.1 d.Postoperative complications occurred in 25.6%of patients.Mean preoperative scoliosis was 58°,pelvic obliquity 16.4°,thoracic kyphosis 55.8°,lumbar lordosis 11.1°,coronal balance 3.8 cm,and sagittal balance+6.1 cm.Mean surgical correction of scoliosis was 79.2%and of pelvic obliquity was 80.8%.Mean follow-up was 10.9 years(range:2-22.5).Twenty-four patients had died at follow-up.Sixteen patients completed the MDSQ at mean age 25.4 years(range 15.2-37.3).Two patients were bed-ridden and 7 were on ventilatory support.Mean MDSQ total score was 38.1.All 16 patients were satisfied with the results of spinal surgery and would choose surgery again if offered.Most patients(87.5%)reported no severe back pain at follow-up.Factors significantly associated with functional outcomes(MDSQ total score)included greater duration of post-operative follow-up,age,scoliosis postoperatively,correction of scoliosis,increased lumbar lordosis postoperatively,and greater age at loss of independent ambulation.CONCLUSION Spinal deformity correction in DMD patients leads to positive long-term effects on QoL and high patient satisfaction.These results support spinal deformity correction to improve long-term QoL in DMD patients.

Prion-like domain disease-causing mutations and misregulation of alternative splicing relevance in limb-girdle muscular dystrophy (LGMD) 1G

Human prion-like proteins often correspond to nucleic acid binding proteins,displaying both globular domains and long intrinsically disordered regions(IDRs)(Harrison and Shorter,2017).Their IDRs are of low complexity and resemble in amino acid composition to the disordered yeast prion domains,being usually enriched in Gln and Asn residues and depleted in hydrophobic and charged residues.Accordingly,these sequence stretches are named prion-like domains(PrLDs).Prion-like proteins can aggregate into amyloid fibrils,which can accommodate incoming protein monomers,propagating thus the polymeric fold,both processes being。

Anesthesia management in a pediatric patient with Becker muscular dystrophy undergoing laparoscopic surgery:A case report

BACKGROUND Patients with Becker muscular dystrophy(BMD)have a high risk of developing hyperkalemia,rhabdomyolysis,and malignant hyperthermia when exposed to volatile anesthetics and depolarizing muscle relaxants.Patients with BMD are also prone to respiratory depression after general anesthesia.Thus,it is extremely challenging for anesthesiologists to manage anesthesia in BMD patients,particularly in pediatric BMD patients.Here,we present successful anesthesia management using transversus abdominis plane block(TAPB)combined with total intravenous anesthesia(TIVA)in a pediatric BMD patient undergoing laparoscopic inguinal hernia repair.CASE SUMMARY A 2-year-old boy,weighing 15 kg,with BMD,was scheduled for laparoscopic inguinal hernia repair.TIVA was used for induction,and continuous infusions of short-acting intravenous anesthetics combined with TAPB were performed for anesthesia maintenance.Moreover,TAPB provided good postoperative analgesia.The patient underwent uneventful surgery and anesthesia,and over the 17 mo follow-up period showed no anesthesia-induced complications.CONCLUSION TAPB combined with TIVA,using short-acting intravenous anesthetic agents,can provide safe and effective anesthesia management in pediatric BMD patients undergoing short-term abdominal surgery.

Myocardial Protection with Beta Blocker Treatment in Infants with Heart Failure Due to Congenital Heart Defects and Duchenne Muscular Dystrophy

Our first intention to treat infants’ heart failure with beta blockers was to improve the clinical condition as shown in our prospective randomized trial. We only use non-selective beta blockers in these infants, carvedilol in those with left ventricular dysfunction and propranolol in those with congenital heart disease without ventricular dysfunction. Despite a significant improvement of Ross’s heart failure score, we could not convince most colleagues within the last 25 years if the concept of neurohumoral activation in heart failure is not well-established pediatric cardiology. Recently, Honghai Liu et al. published that cardiomyocyte cytokinesis failure was increased in congenital heart disease. Inactivation of the beta adreno receptors genes and administration of the beta-blocker propranolol increased cardiomyocyte division in neonatal mice, which increased the number of cardiomyocytes (endowment) and conferred benefit after myocardial infarction in adults. We currently realize that propranolol in infants with congenital heart disease not only decrease highly elevated NT-Pro-BNP values but also decrease cardiac troponin T values that may indicate myocardial injury due to neurohumoral activation. We reproduce this observation, primarily seen in infants with congenital heart disease, in an infant with Duchenne muscular dystrophy. These observations were in good accordance with current data from H. Liu et al., who showed that treatment with non-selective beta blockers early after birth might rescue cytokinesis defects and prevent heart dysfunction in adulthood in a mouse model.

The resistive range of motion exercise training in Duchenne muscular dystrophy:a case study

Background:To determine the effectiveness of resistive range of motion exercises in improving muscle strength and functional abilities in Duchenne muscular dystrophy.The study was also aimed to determine if resistive range of motion exercises can slow down the progression of the disease.Methods:A seven-year-old male child was diagnosed with Duchenne muscle dystrophy presented to outpatient physiotherapy clinic.The patient was presented with difficulty in stair climbing,sitting up from the floor,fatigue,and muscle weakness specifically weakness in the proximal limb muscles.The progressive resistive range of motion training was implemented for four years to improve muscle strength and functional abilities.The medical research council grading scale,north ambulatory assessment scale,and creatine kinase were used to evaluate muscle strength,functional abilities,and creatine kinase levels.Results:The muscular strength and functional abilities did not improve after four years of exercise training.The creatine kinase levels were decreased over the period of four years.Conclusion:Resistive range of motion exercises are helpful in maintaining the muscular strength and functional abilities in Duchenne muscular dystrophy.

Two－step multiplex polymerase chain reaction for gene diagnosis of progressive pseudohypertrophic muscular dystrophy

in the present study,9 exon-containing DNA segments of dystrophin gene with 9 sets of oligonucleotide primers by two-step multiplex polymerase chain reaction (mPCR) were amplified. Subsequently,gene analysis was performed in 36 cases of Duchenne mascular dystroply (DMD) and 4 cases of Becker muscular dystrophy(BMD). The findings showed that 17 cases of deletion were detected by using the first 5 sets of primers with a relatively high incidence of deletion detection and 2 more cases of deletion were detected by using the remaining 4 sets of primers. The total deletion rate detected by mPCR with 9 cases of primers was 47. 5% of the patients examined,suggesting that about 79. 1% of the patients with gene deletion could be detected. Thus,as a preliminary screening, the two-step mPCR can be used in the gene diagnosis of DMD/BMD. The method is not only simple, convenient and rapid,but also free from radiosotope trouble.

Tetramethylpyrazine Nitrone Improved Motor Deficits and Alleviated Dystrophic Muscle Pathology in the <i>mdx</i>Mouse Model of Duchenne Muscular Dystrophy

Duchenne muscular dystrophy (DMD) is a lethal X-linked recessive neuromuscular disorder caused by mutations in the dystrophin encoding gene, with the characteristics of a severe and progressive destruction of muscle structure and function. Skeletal muscle fibrosis is one of the pathological features of DMD. Tetramethylpyrazine (2,3,5,6-tetramethylpyrazine, TMP) has been demonstrated to reduce heart and liver fibrosis. Meanwhile, previous studies showed that Tetramethylpyrazine nitrone (TBN), a nitrone derivative of TMP, has promising therapeutic effects in several neurodegenerative models and is more potent than TMP. In this study, we investigated the potential effect of TBN on the mdx mouse model of DMD. Eight-week-old mdx mice were administered with TBN (30 mg/kg) intragastrically twice daily, with deflazacort (1 mg/kg) once a day as a positive control, for a total of 24 weeks. Behavioral tests including pole-climbing open-field test were monitored every 4 weeks. Histopathological assessment was conducted in the gastrocnemius and diaphragm muscles. The effects of TBN on protein levels of dysferlin were measured by immunohistochemistry. TBN significantly reduced the climbing time in pole test and increased the total distance moved in an open-field test of mdx mice. TBN attenuated fibrosis in the gastrocnemius and diaphragmatic muscles. In addition, TBN protected gastrocnemius muscle fibers via increasing expression of the dysferlin in mdx mice. In conclusion, this study demonstrated that TBN could improve the motor deficits and muscle pathology of mdx mouse, and it is worth further exploring the mechanism of action of TBN for DMD treatment.

Clinical manifestations and prenatal diagnosis of Ullrich congenital muscular dystrophy: A case report

BACKGROUND Ullrich congenital muscular dystrophy(UCMD)is one of the collagen-VI-related myopathies caused by mutations of COL6A1,COL6A2,and COL6A3 genes.Affected individuals are characterized by muscle weakness,proximal joint contracture,distal joint hyperlaxity,and progressive respiratory failure.There is currently no cure for UCMD.Here,we report the clinical manifestations and prenatal diagnosis of compound heterozygous mutations of the COL6A2 gene in a Chinese family with UCMD.CASE SUMMARY A 3-year-old boy,his 4-year-old brother,their parents,and a 20-wk-old fetus in the mother’s womb were included in the study.The brothers had the typical manifestations of the early-severe subtype:A delayed motor milestone(never walking independently),torticollis,scoliosis,proximal joint contracture,distal joint hyperextension,right hip joint dislocation,and calcaneal protuberance.Both brothers were found by whole-exome sequencing and Sanger sequencing to carry two mutations of the COL6A2 gene(c.1353_c.1354insC,p.Arg453Profs-Ter42/c.2105G>A,p.Trp702Ter).The absence of collagen VI staining in the younger brother’s muscle was identified accurately.Genetic counseling and prenatal diagnosis were crucial for the family,as the autosomal recessive genetic disease affected a quarter of the patient’s siblings.The fetus of the mother’s third child underwent prenatal diagnosis and carried the same two mutations of COL6A2,confirmed in the amniotic fluid by multiplex ligation-dependent probe amplification and short tandem repeats.After a painful psychological struggle,the parents finally decided to terminate the pregnancy.CONCLUSION We report a Chinese family suffering from UCMD.By clarifying the COL6A2 mutations in the probands,the parents had the opportunity to opt for voluntary interruption of the third UCMD pregnancy.

Cancer risk among patients with hereditary muscular dystrophies:a population-based study in Taiwan,1997-2009

Muscular dystrophies(MD) comprise a heterogeneous group of hereditary myopathic diseases.In this group,myotonic MD is associated with an increased cancer risk.However,the cancer risk in other types of MD is unclear.To address this gap in knowledge,we assessed data obtained from the Taiwan Health Insurance Program database.A total of 1,272 patients with MD diagnosed between 1997 and 2009 were enrolled.They were followed up for cancer during the same period by record linkage with the cancer certification in Taiwan.Age-and sex-standardized incidence ratios(SIRs) of overall and site-specific cancers were calculated.For congenital and progressive hereditary MD,there were 685 and 505 cases(males:69.5% and 80.6%),the median ages at diagnosis were 16 and 13 years,and the mean follow-up durations were 7.12 and 5.06 years,respectively.In addition,cancers were developed in 10 patients with congenital MD and 3 patients with progressive hereditary MD.Female MD patients exhibited an increased cancer risk,yielding an SIR of 3.37 [95% confidence interval(CI) = 1.38-8.25] in congenital MD and 2.95(95% CI = 0.95-9.19) in hereditary progressive MD.Site-specific cancer SIRs were not powered to be significantly different.In conclusion,genetic defects in hereditary MD may increase cancer risks in females and a sex difference should be further investigated.

磁共振Dixon技术在肌营养不良症中的应用

肌营养不良症(muscular dystrophy,MD)是一组原发于肌肉组织的遗传性变性疾病,其临床特征为缓慢进行性加重的肌无力、肌肉萎缩以及不同程度的运动障碍,肌肉萎缩是由脂肪浸润导致的。Dixon水-脂分离技术能精确定量肌肉脂肪含量,监测疾病进展和评估预后,且具有无创性及可重复性。本文就Dixon技术在肌营养不良症中的应用作出综述。

优化多重PCR检测Duchenne muscular dystrophy基因外显

目的:介绍一种快速简便地优化多重PCR检测DMD基因外显子缺失的方法及详细步骤.方法:采2ml外周血,用0.2%氯化钠处理收集白细胞,再用基因组DNA提取试剂盒抽提基因组DNA,用优化的多重PCR法直接检测DMD基因外显子的缺失.结果:用该方法检测DMD基因外显子缺失结果准确清晰.结论:用优化的多重PCR技术可以直接检测DMD基因外显子缺失,跟通常使用的9对引物一步法相比,具有经济、快速、简便等特点.

Prenatal Diagnosis of Fukuyama Congenital Muscular Dystrophy by Optical Genomic Mapping in a Chinese Family

Fukuyama congenital muscular dystrophy(FCMD)is an autosomal recessive disorder first described by Fukuyama in 1960.1 It typically manifests with generalized muscle weakness and hypotonia from infancy,often requiring assistive devices for mobility.Patients frequently exhibit cognitive deficits,varying degrees of seizures,and specific neuroimaging,such as micropolygyria,hydrocephalus,and cerebellar malformations.