Magnetic resonance imaging of muscle in nemaline myopathy

We report muscle MRI findings of 10 patients from 8 families with nemaline myopathy. Patients with involvement of the nebulin (NEB) gene showed a consistent pattern of selective muscle involvement corresponding to clinical severity. In mild cases, there was complete sparing of thigh muscles and selective involvement of tibialis anterior and soleus. In moderate cases, there was predominant involvement of rectus femoris, vastus lateralis and hamstring muscles and diffuse involvement of anterior compartment and soleus. Patients with nemaline myopathy secondary to mutations in the skeletal muscle -actin (ACTA1) gene showed diffuse involvement of thigh and leg muscles with relative sparing of the gastrocnemii. Selective muscle involvement in both genetic categories was distinct from what has been reported in other congenital myopathies. We conclude that muscle MRI may be applied to distinguish nemaline myopathy from other conditions with similar clinical and histopathological features, to supplement clinical assessment in individual patients and to help direct genetic testing.     

Distinct neuromuscular phenotypes in myotonic dystrophy types 1 and 2

Myotonic Dystrophy Type 1 (DM1) and 2 (DM2) present with distinct though overlapping clinical phenotypes. Comparative imaging data on skeletal muscle involvement are not at present available. We used the novel technique of whole body 3.0 Tesla (T) Magnetic Resonance Imaging (MRI) to further characterize musculoskeletal features in DM2 and compared the results with DM1. MRI findings of 15 DM1 and 14 DM2 patients were evaluated with respect to patterns of skeletal muscle affection and clinical data using the Muscular Impairment Rating Scale (MIRS) and Medical Research Council scale (MRC). All DM1 patients had pathological MRI compared with only 5 DM2 patients. In contrast to DM2, DM1 patients showed a characteristic distribution of muscle involvement with frequent and early degeneration of the medial heads of gastrocnemius muscles, and a perifemoral semilunar pattern of quadriceps muscle affection sparing the rectus femoris. The most frequently affected muscles in DM1 were the medial heads of gastrocnemius, soleus, and vastus medialis muscles. In DM2, however, the erector spinae and gluteus maximus muscles were most vulnerable to degeneration. MRI data were in line with the clinical grading in 12 DM1 and 3 DM2 patients. In 3 DM1 and 5 DM2 patients, MRI detected subclinical muscle involvement. 9 DM2 patients with mild to moderate proximal muscle weakness and/or myalgias had normal MRI. Pathological MRI changes in DM2 emerged with increasing age and were restricted to women. Whole body 3.0T MRI is a sensitive imaging technique that demonstrated a characteristic skeletal muscle affection in DM1. In contrast, MRI was no reliable indicator for skeletal muscle involvement in mildly affected DM2 patients since myalgia and mild paresis were usually not reflected by MRI signal alterations.     

Muscle magnetic resonance imaging and histopathology in ACTA1‐related congenital nemaline myopathy

Introduction: Muscle biopsy is usually diagnostic in nemaline myopathy (NM), but some patients may show nonspecific findings, leading to pitfalls in diagnosis. Muscle MRI is a helpful complementary tool. Methods: We assessed the clinical, histopathological, MRI, and molecular findings in a 19‐year‐old patient with NM in whom 2 muscle biopsies with ultrastructural examination showed no nemaline bodies. We analyzed the degree and pattern of muscle MRI involvement of the entire body, including the tongue and pectoral muscles. Results: Muscle MRI abnormalities in sartorius, adductor magnus, and anterior compartment muscles of the leg suggested NM. A previously unreported fatty infiltration of the tongue was found. A third biopsy after the muscle MRI showed scant nemaline bodies. A novel heterozygous de novo ACTA1 c.611C>T/p.Thr204Ile mutation was detected. Conclusions: We highlight the contribution of muscle imaging in addressing the genetic diagnosis of ACTA1‐related NM. Muscle Nerve 50: 1011–1016, 2014     

Axial myopathy – an unrecognised entity

Axial myopathy (AM) is a rare neuromuscular disorder characterised by selective involvement of the spinal muscles with a bent spine and/or drooping head as leading clinical features. We here report the results of clinical, histopathological, MRI, molecular genetics and electrophysiological investigations carried out on six patients affected by pure axial myopathy. Symptoms appeared within an age range of 35 to 56 years. The first symptoms were difficulty in keeping the trunk and head in an upright position. Both bent spine and dropped head were reduced in a supine position. The disease was slowly progressive. Muscle strength examination and muscle imaging revealed involvement of the spinal and neck extensor muscles only. Serum CK was normal to slightly increased. EMG and muscle biopsy specimens obtained from spinal muscles showed an advanced chronic myopathic pattern. We conclude that axial myopathy may be much more common than previously thought, because gradual progression of cervical kyphosis may often be explained as a feature of normal ageing or as an associated sign of several neurological disorders and vertebral degeneration diseases. Received: 24 June 2001, Received in revised form: 2 November 2001, Accepted: 6 November 2001     

Selective muscle involvement on magnetic resonance imaging in autosomal dominant Emery-Dreifuss muscular dystrophy

OBJECTIVE: The aim of this study was to evaluate the spectrum of muscle involvement on MRI in patients with autosomal dominant Emery-Dreifuss muscular dystrophy (EDMD2) due to mutations in the lamin A/C gene and to compare it to the pattern found in other conditions with similar phenotype. PATIENTS AND METHODS: Nine patients with a diagnosis of EDMD2 had MRI scanning of their leg muscles. Seven other patients, four with the X-linked form of Emery-Dreifuss muscular dystrophy (EDMD) and three with an Emery-Dreifuss-like phenotype but no detectable mutations in either the emerin or the lamin A/C gene were also scanned as disease controls. RESULTS: All patients with EDMD2 showed a characteristic involvement of the posterior calf muscles. The medial head of the gastrocnemius was always predominantly involved while the lateral head was relatively spared. This pattern was more obvious in mildly affected patients in whom the other calf muscles were spared or only mildly involved but was also recognisable in the patients with more advanced disease. In contrast, none of the patients with the X-linked EDMD or with Emery-Dreifuss-like phenotype but no mutation in either genes showed this pattern of muscle involvement. CONCLUSIONS: Our results suggest that patients with EDMD2 have a specific pattern of muscle involvement and that muscle MRI can be used, in combination with other techniques, to distinguish various genetic forms of Emery-Dreifuss muscular dystrophy.     

Imaging methods reveal unexpected patchy lesions in late onset distal myopathy.

Computed tomography (CT), ultrasonography (US) and low field magnetic resonance imaging (MRI) of muscles were performed in 13 patients of a large family with two clinically separate phenotypes of muscular dystrophy. Five patients had severe proximal muscle weakness and wasting like in limb-girdle muscular dystrophy. Imaging methods showed loss of muscle structure and replacement with adipose tissue especially in proximal muscles. Eight patients had distal myopathy of late onset with weakness and wasting of anterior tibial muscles. Imaging methods confirmed fatty degeneration of tibial muscles and, moreover, revealed unexpected large patchy lesions in several other clinically unaffected muscles. Our results indicate that some myopathies which are clinically localized, may actually have a more widespread patchy involvement as revealed by non-invasive imaging methods. In this family CT and MRI were more informative concerning lesions and distribution than US.     

A novel mutation in the PDZ‐like motif of ZASP causes distal ZASP‐related myofibrillar myopathy

Mutations in the LDB3 gene have been identified in patients with Z‐disc‐associated, alternatively spliced, PDZ motif‐containing protein (ZASP)‐related myofibrillar myopathy (ZASP‐MFM) characterized by late‐onset distal myopathy with signs of cardiomyopathy and neuropathy. We describe an autosomal dominant inherited pedigree with ZASP‐MFM that is in line with the typical phenotype of distal myopathy without cardiomyopathy and neuropathy, while mild asymmetrical muscle atrophy can be observed in some affected members. Muscle MRI revealed considerable fatty degeneration involved in the posterior compartment of thigh and lower leg, but relatively preserved in rectus femoris, sartorius, gracilis, adductor longus and biceps femoris breve muscles in the later stage. In addition, fatty infiltration of medial gastrocnemius muscle can be initiated as early as in the third decade in asymptomatic individuals. Myopathological features showed sarcoplasmic accumulation of multiple protein deposits and electron dense filamentous bundle aggregates. A novel heterozygous missense mutation (p.N155H) in a highly conserved PDZ‐like motif of ZASP was identified. The results indicate that typical ZASP‐MFM presenting with late‐onset distal myopathy is commonly associated with mutations in PDZ‐like motif of ZASP. The development of fatty degeneration is consistent with the typical pattern of ZASP‐MFM, and the initial fatty infiltration might be started from medial gastrocnemius muscle. Our study expands the clinical and mutational spectrum of ZASP‐MFM.     

Comparing clinical data and muscle imaging of DYSF and ANO5 related muscular dystrophies

In this retrospective cross-sectional study clinical and muscle imaging data of patients with Miyoshi distal myopathy phenotype (MMD1 and MMD3) and limb girdle muscular dystrophy 2L (LGMD2L) were described. MMD1 and MMD3 are genetically heterogenous diseases based on DYSF and ANO5 gene defects. MMD3 and LGMD2L are clinically different diseases caused by an ANO5 gene defect. All groups showed predominant fatty degeneration of the gluteus minimus muscle and of the posterior segments of the thigh and calf muscles with sparing of the gracilis muscle. Muscle atrophy, hypertrophy and asymmetric muscle involvement on muscle imaging did not differ between groups. The pattern of fatty degeneration of muscles and of muscle weakness shows only minor differences between MMD1 (n = 6) and MMD3 (n = 8) patients with more frequently fatty degeneration of the rectus femoris, anterior tibial, and extensor digitorum muscles and more frequently muscle weakness in the anterior tibial, peroneal and calf muscle in MMD1. In the ANO5 related phenotypes the lateral head of the gastrocnemius muscle was less frequently involved in LGMD2L (n = 13) and no differences in the incidence of muscle weakness was found. Therefore, MMD3 and LGMD2L should be considered as part of one spectrum of ANO5 related muscle disease.     

远端型肌病71例的临床及肌肉病理分析

目的　探讨远端型肌病的临床表现及肌肉病理特点。方法　对71例远端型肌病患者进行回顾性分析。结果　71例患者中,Nonaka型26例,呈散发或常染色体隐性遗传,多以胫前肌无力为首发症状,肌肉坏死较轻,镶边空泡(rimmedvacuole,RV)多见,可见管状细丝包涵体;Miyoshi型38例,呈散发或常染色体隐性遗传,多以腓肠肌力弱为首发症状,肌肉变性坏死严重,RV少见;TMD型2例,均为散发病例,病变主要局限于胫前肌,病情进展较慢,有肌肉变性坏死,可见RV;Welander型4例,呈散发或常染色体显性遗传,以手指、腕部无力为首发症状,可波及下肢远端,轻度肌肉变性坏死,偶可见RV;OPDM型1例,呈常染色体显性遗传,表现为下肢远端肌无力伴眼外肌、面部肌肉、咽肌无力,肌肉坏死不显著,可见RV。结论　在中国Miyoshi型、Nonaka型、TMD型、Welander型及OPDM型远端型肌病均可见到,各型临床表现及病理改变与国外报道基本一致。     

全身性癫癎伴高热惊厥附加症致病基因的连锁定位研究

目的　定位全身性癫癎伴高热惊厥附加症的致病基因。方法　采用全基因组扫描的连锁分析方法对全身性癫癎伴高热惊厥附加症4个家系进行研究。结果　在染色体5q34多点连锁分析显示最大LOD值为3. 815。染色体单体型分析将连锁范围缩小至D5S820至D5S1476之间4. 0厘摩(cM)的区域。结论　全身性癫癎伴高热惊厥附加症致病基因定位在染色体5q34。     

Nonaka肌病临床病理及肌肉磁共振特点分析

目的探讨Nonaka肌病的临床、肌肉病理及肌肉磁共振特点。方法入选2例患者,女性1例,男性1例,临床表现均以双下肢远端肌肉无力、萎缩为主,双上肢仅轻度受累。血清肌酸激酶轻度升高,肌电图提示肌源性损害,神经传导速度均正常。对患者完善大腿及小腿肌肉磁共振检查,并予以左上肢肱二头肌活检,进行组织学、酶组织化学及免疫组织化学染色,抽取外周静脉血2mL送基因公司进行遗传性肌肉病相关基因测序。结果肌肉病理提示,肌纤维肥大、萎缩、再生,肌纤维内可见镶边空泡,符合肌病样病理改变。肌肉MRI提示,大腿股四头肌脂肪化程度较轻,尤其是股外侧肌未受累及,大腿后组肌群及小腿胫前肌、胫后肌脂肪化程度严重。基因结果均提示GNE基因突变。结论 Nonaka肌病是一种与GNE基因突变相关的常染色体隐性遗传性远端肌病,临床表现特点为胫前肌首先受累,而股四头肌早期不受累。病理改变特点为肌纤维内镶边空泡形成。肌肉MRI可提示肌肉脂肪化的程度及分布规律,为诊断提供依据。     

Whole‐body muscle magnetic resonance imaging in SEPN1‐related myopathy shows a homogeneous and recognizable pattern

Introduction: The aim of this study was to delineate the spectrum of muscle involvement in patients with a myopathy due to mutations in SEPN1 (SEPN1‐RM). Methods: Whole‐body magnetic resonance imaging (WBMRI) was used in 9 patients using T1‐weighted turbo spin–echo (T1‐TSE) sequences and short tau inversion recovery (STIR) in 5 patients. Results: Analysis of signal and volume abnormalities by T1‐TSE sequences in 109 muscles showed a homogeneous pattern characterized by a recognizable combination of atrophy and signal abnormalities in selected muscles of the neck, trunk, pelvic girdle, and lower limbs. Severe wasting of sternocleidomastoid muscle and atrophy of semimembranosus were detected. Selective paraspinal, gluteus maximus, and thigh muscle involvement was also observed. The lower leg was less constantly affected. Conclusions: WBMRI scoring of altered signal and atrophy in muscle can be represented by heatmaps and is associated with a homogeneous, recognizable pattern in SEPN1‐RM, distinct from other genetic muscle diseases. Muscle Nerve 52 : 728–735, 2015     

Muscle magnetic resonance imaging abnormalities in X‐linked myopathy with excessive autophagy

Introduction: X‐linked myopathy with excessive autophagy (XMEA) is an X‐linked recessive myopathy due to recently reported mutations in the VMA21 gene. Methods: Four men from 2 separate families were studied. The clinical presentation, genetic data, muscle biopsy, and muscle MRI were analyzed. Results: A known VMA21 mutation, c.163+4A>G, and a new mutation, c.163+3A>G, respectively, were found in the 2 families. The clinical course was characterized by onset in childhood and progressive muscle weakness with a limb‐girdle pattern. Muscle biopsy revealed a mild myopathy with an increased number of giant autophagic vacuoles. Whole‐body muscle MRI showed that pelvic girdle and proximal thighs were the most and earliest affected territories, with sparing of rectus femoris muscles. Muscle changes essentially consisted of degenerative fatty replacement. Conclusions: This study highlights a distinctive MRI pattern of muscle involvement, which can be helpful for diagnosis of XMEA, even before muscle biopsy or genetic analysis. Muscle Nerve 52: 673–680, 2015     

Muscle MRI findings in patients with limb girdle muscular dystrophy with calpain 3 deficiency (LGMD2A) and early contractures

Limb girdle muscular dystrophy 2A is a common variant secondary to mutations in the calpain 3 gene. A proportion of patients has early and severe contractures, which can cause diagnostic difficulties with other conditions. We report clinical and muscle magnetic resonance imaging findings in seven limb girdle muscular dystrophy 2A patients (four sporadic and three familial) who had prominent and early contractures. All patients showed a striking involvement of the posterior thigh muscles. The involvement of the other thigh muscles was variable and was related to clinical severity. Young patients with minimal functional motor impairment showed a predominant involvement of the adductors and semimembranosus muscles while patients with restricted ambulation had a more diffuse involvement of the posterolateral muscles of the thigh and of the vastus intermedius with relative sparing of the vastus lateralis, sartorius and gracilis. At calf level all patients showed involvement of the soleus muscle and of the medial head of the gastrocnemius with relative sparing of the lateral head. MRI findings were correlated to those found in two patients with the phenotype of limb girdle muscular dystrophy 2A without early contractures and the pattern observed was quite similar. However, the pattern observed in limb girdle muscular dystrophy 2A is different from that reported in other muscle diseases such as Emery-Dreifuss muscular dystrophy and Bethlem myopathy which have a significant clinical overlap with limb girdle muscular dystrophy 2A once early contractures are present. Our results suggest that muscle MRI may help in recognising patients with limb girdle muscular dystrophy 2A even when the clinical presentation overlaps with other conditions, and may therefore, be used as an additional investigation to target the appropriate biochemical and genetic tests.     

Magnetic resonance imaging phenotyping of Becker muscular dystrophy

Introduction: There is little information on magnetic resonance imaging (MRI) phenotypes of Becker muscular dystrophy (BMD). This study presents the MRI phenotyping of the upper and lower extremities of a large cohort of BMD patients. Methods: In this retrospective study, MRI images of 33 BMD subjects were evaluated for severity, distribution, and symmetry of involvement. Results: Teres major, triceps long head, biceps brachii long head, gluteus maximus, gluteus medius, vasti, adductor longus, adductor magnus, semitendinosus, semimembranosus, and biceps femoris muscles showed the highest severity and frequency of involvement. All analyzed muscles had a high frequency of symmetric involvement. There was significant variability of involvement between muscles within some muscle groups, most notably the arm abductors, posterior arm muscles, medial thigh muscles, and lateral hip rotators. Conclusions: This study showed a distinctive pattern of involvement of extremity muscles in BMD subjects. Muscle Nerve 50: 962–967, 2014     

Combining MRI and muscle biopsy improves diagnostic accuracy in subacute‐onset idiopathic inflammatory myopathy

Introduction: In 10–20% of patients with subacute‐onset idiopathic inflammatory myopathy (IIM), muscle biopsy is normal or shows nonspecific findings. MRI can be used as a triage test before muscle biopsy and as an add‐on test if the biopsy is nondiagnostic. Methods: MRI scans of skeletal muscles and muscle biopsies were evaluated prospectively in 48 patients suspected to have IIM. The interpretations of MRI and muscle biopsy were compared with the definite diagnosis (based on European Neuromuscular Centre criteria and response to corticosteroids). Results: The false negative rate (FNR) of all muscle biopsies was 0.23. Biopsies of a muscle showing hyperintensity on MRI (as triage test) had an FNR of 0.19. The result of MRI as an add‐on test in patients with a nondiagnostic muscle biopsy decreased the FNR from 0.23 to 0.06. Conclusions: We recommend both MRI and muscle biopsy in patients suspected of having IIM. Muscle Nerve 51 : 253–258, 2015     

Infantile autosomal dominant distal myopathy.

Introduction – Distal myopathies are currently regarded as a non-homogeneous group of disorders including different autosomal dominant, recessive and sporadic forms. Material and methods - The cases of a mother and her son and daughter are described and compared to previously reported cases from 4 families. Despite minor differences, the clinical picture is remarkably homogeneous, both within the same family and among different families. Conclusion - A distinct clinical form can be identified including: a) autosomal dominant inheritance; b) onset in infancy or childhood with peroneal muscles weakness; c) not disabling evolution in spite of possible late involvement of muscles others than tibio-peroneal; d) usually normal serum CK and other muscle enzymes; e) EMG evidence of primary myogenic damage; f) morphological findings of non-specific myopathy. Because of the benign evolution and the absence of true dystrophic changes in most biopsies we suggest the term infantile autosomal dominant distal myopathy should be preferred to infantile autosomal dominant distal muscular dystrophy.     

Upper body involvement in GNE myopathy assessed by muscle imaging

Upper body muscle involvement has never been systematically investigated in GNE myopathy (GNEM). Aims of our study were to explore upper body involvement in GNEM patients by means of muscle MRI, to compare the degree of pathology with that of lower body and to validate the MRI pattern of the lower limbs in novel patients. MRI scans of 9 GNEM patients were retrospectively evaluated. T1-weighted and short-tau inversion recovery images were scored. As a result, serratus anterior was involved in all patients, followed by subscapularis and trapezius muscles. The majority of scans consistently showed hypotrophy of pectoralis minor. Conversely, cranial muscles including the tongue were always spared while pectoralis major and latissimus dorsi were relatively spared. We confirmed the known pattern of involvement in the pelvic girdle and limbs, that were more significantly affected than the upper girdle in all disease stages. Paraspinal muscles were also frequently affected displaying both a cranio-caudal and latero-medial gradient of severity along the body axis. Upper girdle MRI highlights a selective muscle involvement in GNEM, offering an added value in patients’ diagnostic workup and deep stratification.     

Pure quadriceps myopathy in two sisters

The authors carried out a clinical, laboratory and muscle computed tomographgy CT follow-up study of 18-21 years on two sisters affected by quadriceps myopathy (QM). The onset in the fourth decade was a weakness in the thighs. During the follow-up study, the patients showed only vasti muscles involvement, normal creatine kinase (CK) levels, myopathic muscle biopsy and electromyography (EMG) and normal membrane protein expression on immunocytochemical analysis. Therefore, all muscle pathologies known to have quadriceps involvement as a leading feature have been ruled out. We conclude that our patients have pure QM with probable autosomal recessive inheritance.     

Decomposition-based quantitative electromyography in the evaluation of muscular dystrophy severity

Introduction: Electromyography is useful in the diagnosis of myopathies, but its utility in determining disease severity requires further investigation. In this study we aimed to determine whether decomposition‐based quantitative electromyography (DQEMG) could indicate the severity of involvement in a cohort of patients with muscular dystrophies (MDs). Methods: Fifteen patients with facioscapulohumeral (FSHD), limb‐girdle (LGMD), and Becker (BMD) muscular dystrophy, and 7 healthy controls, participated in this investigation. Knee extensor isometric strength differentiated the “more severe” and “less severe” MD groups. The vastus lateralis (VL), biceps brachii (BB), and tibialis anterior (TA) muscle groups were investigated using DQEMG. Results: All muscles from the MD group showed changes in mean MUP (motor unit potential) AAR (area‐to‐amplitude ratio), and turns, compared with controls (P < 0.05). More severely affected muscles (VL and BB) also had shortened mean MUP durations compared with controls (P < 0.01). Conclusions: DQEMG was capable of indicating the severity of MD involvement, as changes in MUP morphology reflected the progressive nature of the disease. Muscle Nerve, 2012