Cardiac ankyrin repeat protein is preferentially induced in atrophic myofibers of congenital myopathy and spinal muscular atrophy

Cardiac ankyrin repeat protein (CARP), which is structurally characterized by the presence of four ankyrin repeat motifs in its central region, is believed to be localized in the nucleus and to participate in the regulation of cardiac-specific gene expression in cardiomyocytes. However, we recently found that CARP was induced in skeletal muscle by denervation, leading us to speculate that CARP may be induced under some pathological conditions. In the present study, we immunohistochemically analyzed the expression of CARP in 11 cases of spinal muscular atrophy (SMA) and 14 cases of congenital myopathy. In SMA, CARP was expressed selectively in severely atrophic myofibers, suggesting that CARP expression may reflect the status of muscle atrophy. Furthermore, in the congenital myopathies, the expression patterns of CARP were distinct among the subtypes, which included nemaline myopathy, myotubular myopathy, central core disease, and congenital fiber type disproportion. Although CARP was preferentially expressed in severely damaged myofibers in nemaline myopathy, it was not detected in central core disease. These findings suggest that immunohistochemical evaluation of CARP may be helpful in the diagnosis of SMA and the congenital myopathies.     

杆状体肌病12例患者临床与病理特点

目的 探讨杆状体肌病患者临床与病理特点.方法 采用肌肉酶组织化学染色方法和电镜技术观察12例杆状体肌病患者病理特点,收集临床资料进行归纳分析.结果 在本组12例杆状体肌病患者中,7例为先天轻症型,表现为下肢或四肢无力起病,病程进展缓慢,呈良性过程;3例为儿童起病型,均表现为下肢无力,病程持续加重,有肌萎缩现象;2例为成人起病型,双下肢无力起病,累及上肢肌和延髓部肌肉,进展较快,肌萎缩明显,1例出现呼吸困难.部分病例出现狭长面容、双侧弓形足等发育畸形,血清肌酸激酶值正常或稍高,肌电图提示为肌源性损害.在所有患者的肌肉病理切片中,有半数以上肌纤维均出现成堆的杆状体结构;Ⅰ型纤维占优势并呈萎缩现象,且杆状体均出现在Ⅰ型纤维中;改良Gomori染色时杆状体结构最清楚;电镜观察到部分肌原纤维发育不良,如肌丝断裂,排列不整和肌原纤维粗细不一,肌原纤维Z线细小、不规则或消肖失;大量电子密度高的杆状体结构主要出现在肌膜下的肌核周围,少数在肌纤维中央;高倍电镜观察到杆状体结构实际上是肌原纤维中的一段,只是密度很高,但也可是一块无结构的高电子密度体.结论 本组具有3个类型,成人型病情较重,半数以上肌纤维出现杆状体成堆是诊断的关键,电镜有助于确诊.     

M蛋白相关性杆状体肌病3例及文献回顾

目的 对3例怀疑M蛋白相关性杆状体肌病患者进行肌肉病理检查、M蛋白筛查明确诊断,提高对这一罕见疾病的认识并探讨对此疾病的诊疗方案。 方法 报道3例M蛋白相关性杆状体肌病,结合文献复习对病例特点进行总结。 结果 3例患者均表现为进行性加重的肌肉无力症状,完善肌肉活检诊断为杆状体肌病,合并M蛋白,给予行自体造血干细胞移植治疗有效。 结论 散发的晚发型成人杆状体肌病是一种罕见的、亚急性进展的肌病,常合并M蛋白,针对清除M蛋白的治疗是有效的。     

Severe Neonatal Nemaline Myopathy—Histological and Histochemical Studies of Respiratory Muscles—

The histological and histochemical findings in the respiratory muscles of a patient with severe neonatal nemaline myopathy are described. The patient suffered from frequent pneumonia associated with vomiting due to gastroesophageal reflux and died at 3 months from respiratory failure. The diaphragm was moderately involved and the intercostal muscles mildly involved. Core/targetoid structures were observed in the diaphragm and intercostal muscles.     

Sporadic late onset nemaline myopathy responsive to IVIg and immunotherapy

Sporadic late onset nemaline myopathy (SLONM) is a progressive myopathy of indeterminate etiology and poor outcome. If associated with a monoclonal gammopathy, SLONM carries a more unfavorable prognosis. Immunotherapy was unsuccessful. We report two HIV‐negative SLONM/monoclonal gammopathy patients who improved following intravenous immunoglobulin (IVIg) treatment alone or in combination with immunosuppressant agents. This favorable response to treatment suggests that a dysimmune mechanism is operative in some SLONM individuals. We suggest that IVIg deserves initial consideration for SLONM therapy. Muscle Nerve, 2010     

Nemaline body myopathy caused by a novel mutation in troponin T1 (TNNT1)

Introduction: Nemaline myopathy is a rare disorder characterized by skeletal muscle weakness of varying severity and onset, with the presence of nemaline rods on muscle biopsy. Congenital nemaline body myopathy due to mutations in TNNT1 has hitherto only been described as a result of a single founder mutation in patients of Amish origin and in 2 other individuals with different recessive mutations. Methods: Autozygosity mapping and whole exome sequencing were applied after we identified 9 Palestinian patients from 7 unrelated families who have nemaline myopathy. Results: All patients were homozygous for a novel complex rearrangement of the TNNT1 gene (c.574_577delinsTAGTGCTGT | NM_003283) leading to C‐terminal truncation of the protein (p.L203* | NP_003274.3). Their clinical course was remarkable for early respiratory failure and striking stiffness of the cervical spine. Conclusions: This report exemplifies the utility of combining autozygosity mapping and whole exome sequencing and expands the phenotype associated with TNNT1 mutations. Muscle Nerve 53 : 564–569, 2016     

NEB‐related core‐rod myopathy with distinct clinical and pathological features

Introduction: Mutations in the gene encoding nebulin (NEB) are known to cause several types of congenital myopathy including recessive nemaline myopathy and distal nebulin myopathy. Core‐rod myopathy has recently been reported to be another type of NEB‐related myopathy, and is pathologically characterized by the coexistence of cores and nemaline rods within muscle fibers. Methods: We describe 2 patients with core‐rod myopathy who were analyzed genetically by whole exome sequencing and evaluated clinically and pathologically. Findings were compared with those of patients with the disease of other genetic causes. Results: Three NEB mutations were identified, 2 of which were novel. Mild clinical features, unusual patterns of muscle involvement, and atypical pathological findings were observed. Conclusions: We propose that the clinical and pathological spectrum of core‐rod myopathy should be widened. A significant amount of residual nebulin expression is believed to contribute to the much milder phenotype exhibited by the patients we describe here. Muscle Nerve 53: 479–484, 2016     

Adult nemaline myopathy with trabecular muscle fibers

The term “trabecular myopathy” has been used to designate a syndrome resembling limb‐girdle muscular dystrophy in which the predominant pathological feature is an abundance of lobulated or trabecular muscle fibers. However, the validity of this nosological entity has not been verified. Herein we describe a 63‐year‐old man with a severe, progressive myopathy who exhibited the typical pathological features of both trabecular myopathy and nemaline myopathy in association with a biclonal gammopathy. In this case, adult‐onset nemaline myopathy was probably the primary disease process. The diagnostic significance of trabecular muscle fibers remains uncertain. Muscle Nerve, 2008     

Follow-up studies in a case of unusual congenital myopathy,suggestive of nemaline type

Summary A 20-month-old boy — offspring of consanguinous parents, whose mother presumably had subclinical myopathy — presented with clinical signs of congenital non-progressive myopathy, neurogenic-myogenic electromyographic findings and normal motor conduction velocity. Biopsy of quadriceps muscle showed fiber-type disproportion with hypotrophic type 1, hypertrophic 2A and absent 2B fibers. Subsarcolemmal segmental foci of abnormally, in part regularly arranged bundles of mostly thin myofilaments were found in 13% of hypotrophic type 1 fibers. Rods were seen in only 1 fiber out of 20 tissue blocks. Reexamination 6 years later revealed slightly increased muscle force, myopathic EMG pattern and borderline motor and sensory nerve conduction velocities. Biopsy specimen from deltoid muscle consisted of untypable fibers of varying diameters with jagged Z-lines and increased variability of myofibrillar diameters. Multiple rods were present in 1% of the fibers, the formerly seen segmental foci in 0.1% only. Several intramuscular nerves were normal. The case contributes some new features to the spectrum of congenital myopathies of the nemaline type and suggests different stages of arrested maturation of type 1 fibers at least in this particular case.