Expansion of GGC Repeat in GIPC1 Is Associated with Oculopharyngodistal Myopathy.

Oculopharyngodistal myopathy (OPDM) is an adult-onset inherited neuromuscular disorder characterized by progressive ptosis, external ophthalmoplegia, and weakness of the masseter, facial, pharyngeal, and distal limb muscles. The myopathological features are presence of rimmed vacuoles (RVs) in the muscle fibers and myopathic changes of differing severity. Inheritance is variable, with either putative autosomal-dominant or autosomal-recessive pattern. Here, using a comprehensive strategy combining whole-genome sequencing (WGS), long-read whole-genome sequencing (LRS), linkage analysis, repeat-primed polymerase chain reaction (RP-PCR), and fluorescence amplicon length analysis polymerase chain reaction (AL-PCR), we identified an abnormal GGC repeat expansion in the 5' UTR of GIPC1 in one out of four families and three sporadic case subjects from a Chinese OPDM cohort. Expanded GGC repeats were further confirmed as the cause of OPDM in an additional 2 out of 4 families and 6 out of 13 sporadic Chinese individuals with OPDM, as well as 7 out of 194 unrelated Japanese individuals with OPDM. Methylation, qRT-PCR, and western blot analysis indicated that GIPC1 mRNA levels were increased while protein levels were unaltered in OPDM-affected individuals. RNA sequencing indicated p53 signaling, vascular smooth muscle contraction, ubiquitin-mediated proteolysis, and ribosome pathways were involved in the pathogenic mechanisms of OPDM-affected individuals with GGC repeat expansion in GIPC1. This study provides further evidence that OPDM is associated with GGC repeat expansions in distinct genes and highly suggests that expanded GGC repeat units are essential in the pathogenesis of OPDM, regardless of the genes in which the expanded repeats are located.

Sporadic late-onset nemaline myopathy as a rare cause of slowly progressive muscle weakness with young adult onset.

INTRODUCTION: Sporadic late-onset nemaline myopathy (SLONM) is a rare intractable acquired myopathy characterized by progressive muscle weakness and atrophy, usually with middle to late adult onset. Autologous peripheral blood stem cell transplantation (auto-PBSCT) has been reported to be a promising treatment for SLONM. METHODS: In this study we performed clinical characterization, muscle histopathological analysis, and muscle power monitoring after auto-PBSCT in a 27-year-old HIV-negative man with monoclonal gammopathy. RESULTS: He showed improved muscle strength after treatment with high-dose melphalan and auto-PBSCT. CONCLUSIONS: Considering the recent reports of successful treatment of SLONM, early and correct diagnosis of this condition in association with monoclonal gammopathy is important. SLONM should be added to the list of diseases to consider in the differential diagnosis of progressive muscle weakness with young adult onset.

Memory impairment following right cerebellar infarction: a case study.

We reported a patient with a right cerebellar infarction who showed anterograde amnesia. Cognitive dysfunction caused by cerebellar lesions was called cerebellar cognitive affective syndrome, and deactivation of the contralateral prefrontal cortex function due to disconnections of cerebello-cerebral fiber tracts have been hypothesized as mechanism underlying the syndrome. The episodic memory impairment, however, could not be supported by the same mechanism because the prefrontal lesions cannot cause amnesia syndrome. The feature of the impairment of our patient was similar to that of diencephalic amnesia, and a single photon emission computed tomography study showed a relative hypoperfusion in the right cerebellar hemisphere and left anterior thalamus. We considered that the memory deficit was caused by the dysfunction of the thalamus, which is a relay center of the cerebello-cerebral connectivity network.

Increased gene dosage of myelin protein zero causes Charcot-Marie-Tooth disease.

OBJECTIVE: On the basis of the hypothesis that copy number mutations of the genes encoding myelin compact proteins are responsible for myelin disorders in humans, we have explored the possibility of copy number mutations in patients with Charcot-Marie-Tooth disease (CMT) whose responsible genes remain undefined. METHODS: A family with 6 affected members in 3 consecutive generations, presenting with motor and sensory demyelinating polyneuropathy, was investigated. Characteristic clinical features in this pedigree include Adie pupils and substantial intrafamilial variability in the age at onset, electrophysiological findings, and clinical severity. Nucleotide sequence analyses of PMP22, MPZ, or GJB1 and gene dosage study of PMP22 did not reveal causative mutations. Hence, we applied a custom-designed array for comparative genomic hybridization (CGH) analysis to conduct a comprehensive screening of copy number mutations involving any of the known causative genes for CMT other than PMP22. RESULTS: The array CGH analyses revealed increased gene dosage involving the whole MPZ, and the flanking genes of SDHC and C1orf192. The gene dosage is estimated to be 5 copies. This mutation showed complete cosegregation with the disease phenotype in this pedigree. INTERPRETATION: The increased gene dosage of MPZ and increased expression level of MPZ mRNA emphasize the important role of the dosage of the MPZ protein in the functional integrity of peripheral nerve myelin in humans, and provide a new insight into the pathogenic mechanisms underlying CMT.

Inflammatory myopathies associated with anti-mitochondrial antibodies.

Anti-mitochondrial antibodies, the characteristic markers of primary biliary cirrhosis, have been detected in most patients with this disease. However, the prevalence of these antibodies in inflammatory myopathies and their clinical and histopathological significance has not been determined. Sera from 212 consecutive patients with inflammatory myopathies were screened for anti-mitochondrial antibodies by enzyme-linked immunosorbent assay. The clinical and histopathological features of anti-mitochondrial antibody-positive patients were analysed and statistically compared with those of anti-mitochondrial antibody-negative patients. Twenty-four patients positive for anti-mitochondrial antibodies (seven patients with and 17 patients without primary biliary cirrhosis) were identified (11.3%). Thirteen patients had a clinically chronic disease course of >12 months before their diagnosis at hospitals. Six of these 13 patients (four asymptomatic patients with increased creatine kinase levels and two patients with arrhythmia) had not been aware of muscle weakness, but all 13 patients had muscle atrophy at initial presentation. As complications, eight patients had cardiac involvement including arrhythmias (five patients with supraventricular tachycardia; two with ventricular tachycardia; and one patient with atrioventricular block), six patients had moderately decreased ejection fraction and six patients had decreased vital capacity, two of whom required respiratory support. Regarding muscle histopathological findings, in addition to inflammation, 13 patients had chronic myopathic changes and six had granulomatous lesions. Statistical analysis showed that the clinical features of a chronic disease course, cardiac involvement and muscle atrophy, and the histopathological features of chronic myopathic changes and granulomatous inflammation, were significantly more frequently observed in patients with anti-mitochondrial antibody-positive inflammatory myopathy than in patients who were negative for anti-mitochondrial antibodies. Except for cardiac involvement, which is more frequently observed in patients with primary biliary cirrhosis, no significant differences in clinical or histopathological features were found between patients with or without primary biliary cirrhosis. Our study revealed that inflammatory myopathies associated with anti-mitochondrial antibodies were frequently found in patients with the clinical features of a chronic disease course, muscle atrophy and cardiopulmonary involvement, and the characteristic histopathological feature of granulomatous inflammation. Our study suggests that inflammatory myopathies associated with anti-mitochondrial antibodies form a characteristic subgroup.

Anti-nuclear matrix protein 2 antibody-positive dermatomyositis with gastrointestinal ulcers: A case report.

Gastrointestinal manifestations are a very rare complication of dermatomyositis (DM) and are much less frequent in adult cases than in juvenile cases. Only a few previous papers have reported adult patients who had DM with anti-nuclear matrix protein 2 (anti-NXP2) antibodies and who developed gastrointestinal ulcers. Herein, we report a similar case of a 50-year-old man who had DM with anti-NXP2 antibodies followed by relapsing multiple gastrointestinal ulcers. Even after the administration of prednisolone, his muscle weakness and myalgia deteriorated and gastrointestinal ulcers relapsed. In contrast, intravenous immunoglobulin and azathioprine improved his muscle weakness and gastrointestinal ulcers. Based on the parallel disease activity of the muscular and gastrointestinal symptoms, we considered that his gastrointestinal ulcers were a complication of DM with anti-NXP2 antibodies. We also propose that early intensive immunosuppressive therapy would be required for the muscular and gastrointestinal symptoms in DM with anti-NXP2 antibodies.

The effect of immunosuppressive therapy on cardiac involvements in anti-mitochondrial antibody-positive myositis.

AIMS: Anti-mitochondrial antibody (AMA)-positive myositis is frequently associated with various cardiac involvements, such as arrhythmia and left ventricular (LV) dysfunction. However, the efficacy of immunosuppressive therapy in these complications remains unknown. This study aimed to investigate the cardiac response to immunosuppressive therapy in patients with AMA-positive myositis. METHODS AND RESULTS: The clinical data of 15 AMA-positive myositis patients with cardiac involvement were retrospectively collected at our centre. To evaluate the effects of immunosuppressive therapy, echocardiographic and laboratory data of patients who received glucocorticoid therapy with additional immunosuppressants (n = 6) and those who did not (n = 6) were compared. Also, the characteristics of patients with or without >5% LV ejection fraction (LVEF) decline during the follow-up period (n = 5 vs. n = 7) were compared. Thirteen patients (87%) had arrhythmias, and eight patients (53%) had LV wall motion abnormalities. Although arrhythmias decreased after treatment, reduced LVEF and LV wall motion abnormalities persisted. Further investigation revealed an increased LV end-systolic dimension and reduced LVEF in patients without additional immunosuppressive therapy, while those in patients with additional immunosuppressive therapy were maintained. Six of seven patients (86%) without LVEF decline received additional immunosuppressive therapy, whereas no patients with LVEF decline had additional immunosuppressive therapy. CONCLUSIONS: Cardiac involvement in AMA-positive myositis may worsen even with glucocorticoid monotherapy, and there might be some associations between the change of LV function and additional immunosuppressive therapy.

[Idiopathic Inflammatory Myopathy and Anti-aminoacyl-tRNA Synthetase Antibody].

Anti-aminoacyl-tRNA synthetase (ARS) antibodies (anti-Jo-1, anti-PL-7, anti-PL-12, anti-EJ, anti-KS, anti-OJ, anti-Ha, and anti-Zo antibodies) are found in 25 to 40% of myositis patients. The patients with these antibodies have anti-synthetase syndrome with one or more of the following clinical features: myositis, interstitial lung disease, arthritis, fever, Raynaud's phenomenon, and mechanic's hands. In Japan, health insurance coverage of treatments for patients in whom the "anti-ARS antibodies," anti-Jo-1, anti-PL-7, anti-PL-12, anti-EJ, and anti-KS are detected by enzyme-linked immunosorbent assay was approved by the Ministry of Health, Labour and Welfare in 2014. Recently, clinical features have been discovered to be heterogeneous. Patients with the anti-PL-7, anti-PL-12, anti-KS, and anti-OJ antibodies exhibit interstitial lung disease rather than myositis. Interstitial lung disease is related to the prognosis of this syndrome. Regarding histopathological findings of the muscle, perimysial connective tissue fragmentation with positive staining for alkaline phosphatase is the characteristic feature. Myonuclear actin filament inclusions are also detected. A recent work demonstrated that immunization of mice with histidyl-tRNA synthetase results in muscle inflammation consistent with myositis. These findings promote understanding of the pathological mechanism of the development of myositis associated with anti-ARS antibodies.

Clinicopathologic features of myositis patients with CD8-MHC-1 complex pathology.

OBJECTIVE: To determine the clinical features of myositis patients with the histopathologic finding of CD8-positive T cells invading non-necrotic muscle fibers expressing major histocompatibility complex class 1 (CD8-MHC-1 complex), which is shared by polymyositis (PM) and inclusion body myositis (IBM), in relation to the p62 immunostaining pattern of muscle fibers. METHODS: All 93 myositis patients with CD8-MHC-1 complex who were referred to our hospital from 1993 to 2015 were classified on the basis of the European Neuromuscular Center (ENMC) diagnostic criteria for IBM (Rose, 2013) or PM (Hoogendijk, 2004) and analyzed. RESULTS: The 93 patients included were 17 patients with PM, 70 patients with IBM, and 6 patients who neither met the criteria for PM nor IBM in terms of muscle weakness distribution (unclassifiable group). For these PM, IBM, and unclassifiable patients, their mean ages at diagnosis were 63, 70, and 64 years; autoimmune disease was present in 7 (41%), 13 (19%), and 4 (67%); hepatitis C virus infection was detected in 0%, 13 (20%), and 2 (33%); and p62 was immunopositive in 0%, 66 (94%), and 2 (33%), respectively. Of the treated patients, 11 of 16 PM patients and 4 of 6 p62-immunonegative patients in the unclassifiable group showed responses to immunotherapy, whereas all 44 patients with IBM and 2 p62-immunopositive patients in the unclassifiable group were unresponsive to immunotherapy. CONCLUSIONS: CD8-MHC-1 complex is present in patients with PM, IBM, or unclassifiable group. The data may serve as an argument for a trial of immunosuppressive treatment in p62-immunonegative patients with unclassifiable myositis.

Chronic Myopathy Associated With Anti-Signal Recognition Particle Antibodies Can Be Misdiagnosed As Facioscapulohumeral Muscular Dystrophy.

OBJECTIVES: To report cases of chronic autoimmune necrotizing myopathy with anti-signal recognition particle antibodies (anti-SRP myopathy) initially misdiagnosed as muscular dystrophy, in particular, facioscapulohumeral muscular dystrophy (FSHD). METHODS: Medical records of patients with anti-SRP myopathy in our institution were retrospectively reviewed. RESULTS: All 6 patients were initially diagnosed with muscular dystrophy because of the long-term clinical course and lack of inflammation on biopsy; 5 were diagnosed with FSHD based on a winged scapula. However, the following features suggested an alternative diagnosis, leading to anti-SRP antibody measurement: (1) lack of family history, (2) lack of facial involvement and asymmetry, (3) prominent dysphagia, and (4) profuse spontaneous activities on needle electromyography. All patients showed improvement with immunomodulating therapy. CONCLUSIONS: Anti-SRP antibody measurement should be considered in patients diagnosed with FSHD if they present with diagnostic hallmarks of anti-SRP myopathy listed above, to avoid oversight of this potentially treatable disorder.

Anti-TIF1-γ antibody and cancer-associated myositis: A clinicohistopathologic study.

OBJECTIVE: We aimed to analyze the clinical and histopathologic features of cancer-associated myositis (CAM) in relation to anti-transcriptional intermediary factor 1 γ antibody (anti-TIF1-γ-Ab), a marker of cancer association. METHODS: We retrospectively studied 349 patients with idiopathic inflammatory myopathies (IIMs), including 284 patients with pretreatment biopsy samples available. For the classification of IIMs, the European Neuromuscular Center criteria were applied. Patients with CAM with (anti-TIF1-γ-Ab[+] CAM) and without anti-TIF1-γ-Ab (anti-TIF1-γ-Ab[-] CAM) were compared with patients with IIM without cancers within and beyond 3 years of myositis diagnosis. RESULTS: Cancer was detected in 75 patients, of whom 36 (48%) were positive for anti-TIF1-γ-Ab. In anti-TIF1-γ-Ab(+) patients with CAM, cancers were detected within 1 year of myositis diagnosis in 35 (97%) and before 1 year of myositis diagnosis in 1. All the anti-TIF1-γ-Ab(+) patients with CAM satisfied the dermatomyositis (DM) criteria, including 2 possible DM sine dermatitis cases, and were characterized histologically by the presence of perifascicular atrophy, vacuolated fibers (VFs), and dense C5b-9 deposits on capillaries (dC5b-9). In contrast, 39 anti-TIF1-γ-Ab(-) patients with CAM were classified into various subgroups, and characterized by a higher frequency of necrotizing autoimmune myopathy (NAM). Notably, all 7 patients with CAM classified into the NAM subgroup were anti-TIF1-γ-Ab(-) and exhibited no dC5b-9 or VFs. CONCLUSIONS: CAM includes clinicohistopathologically heterogeneous disease entities. Among CAM entities, anti-TIF1-γ-Ab(+) CAM has characteristically shown a close temporal association with cancer detection and the histopathologic findings of dC5b-9 and VFs, and CAM with NAM is a subset of anti-TIF1-γ-Ab(-) CAM.