Defining the landscape of TIA1 and SQSTM1 digenic myopathy.

TIA1/SQSTM1 myopathy is one of the few digenic myopathies. We describe four new French adult male patients carrying the TIA1 p.Asn357Ser and SQSTM1 p.Pro392Leu variant and review the literature to include 20 additional cases to define the spectrum of the disease. These twenty-four patients (75% males) had late-onset (52,6 ± 10,1 years), mainly asymmetric, distal ankle and hand finger extension weakness (75%), mild CK elevation (82.4%) and myopathic EMG. Two of the four French patients had sensorimotor axonal polyneuropathy and an additional one had neurogenic changes in muscle biopsy. Muscle biopsy showed rimmed vacuoles (44.4%), myofibrillar disorganization (16.7%) or both (38.9%), with P62/TDP43 aggregates. The TIA1 p.Asn357Ser variant was present in all patients and the SQSTM1 p.Pro392Leu was the most frequent (71%) of the four reported SQSTM1 variants. We reviewed the distal myopathy gene panels of Pitié-Salpêtrière's hospital cohort finding a prevalence of 11/414=2.7% of the TIA1 p.Asn357Ser variant, with two patients having an alternative diagnosis (TTN and MYH7) with atypical phenotypes, resembling some of the features seen in TIA1/SQSTM1 myopathy. Overall, TIA1/SQSTM1 myopathy has a homogenous phenotype reinforcing the pathogenicity of its digenic variants. We confirm an increased burden of the TIA1 p.Asn357Ser variant in distal myopathy patients which could act as a genetic modifier.

Granulomatous myositis: characteristics and outcome from a monocentric retrospective cohort study.

Granulomatous myositis is a clinical-pathological entity, which has been rarely reported, mostly described in sarcoidosis. Currently, no clear and simple prognostic factor has been identified to predict granulomatous myositis evolution. The clinical, anatomopathological, imaging, and biological characteristics of 26 patients with granulomatous myositis were retrospectively collected to describe clinical presentation and outcomes of this condition. Twenty-six patients with granulomatous myositis were included (14 males) with a median age of symptom onset of 65 years. 54 % of patients presented a severe form of the disease defined as a Rankin score ≥2 at last follow-up visit or a progressive form of the disease (no improvement under treatment). Etiology were sarcoidosis (n = 14), inclusion body myositis (n = 4), autoimmune disease (n = 1), hematological malignancy (n = 1), and idiopathic (n = 6). Distal deficit and amyotrophy were more frequent among those with a severe disease. Corticosteroids led to improvement in 75 % of cases, but 66 % of responders relapsed. Methotrexate appeared as a promising second line therapy with clinical improvement in 50 % of patients, and no relapse in responders. Granulomatous myositis is often a severe and difficult-to-treat disease in which patients frequently progress towards severe disability. The presence of muscle atrophy and distal weakness appears to be frequently associated with a severe form of the disease.

Anti-Ku + myositis: an acquired inflammatory protein-aggregate myopathy.

Myositis with anti-Ku-autoantibodies is a rare inflammatory myopathy associated with various connective tissue diseases. Histopathological studies have identified inflammatory and necrotizing aspects, but a precise morphological analysis and pathomechanistic disease model are lacking. We therefore aimed to carry out an in-depth morpho-molecular analysis to uncover possible pathomechanisms. Muscle biopsy specimens from 26 patients with anti-Ku-antibodies and unequivocal myositis were analyzed by immunohistochemistry, immunofluorescence, transcriptomics, and proteomics and compared to biopsy specimens of non-disease controls, immune-mediated necrotizing myopathy (IMNM), and inclusion body myositis (IBM). Clinical findings and laboratory parameters were evaluated retrospectively and correlated with morphological and molecular features. Patients were mainly female (92%) with a median age of 56.5 years. Isolated myositis and overlap with systemic sclerosis were reported in 31%, respectively. Isolated myositis presented with higher creatine kinase levels and cardiac involvement (83%), whereas systemic sclerosis-overlap patients often had interstitial lung disease (57%). Histopathology showed a wide spectrum from mild to pronounced myositis with diffuse sarcolemmal MHC-class I (100%) and -II (69%) immunoreactivity, myofiber necrosis (88%), endomysial inflammation (85%), thickened capillaries (84%), and vacuoles (60%). Conspicuous sarcoplasmic protein aggregates were p62, BAG3, myotilin, or immunoproteasomal beta5i-positive. Proteomic and transcriptomic analysis identified prominent up-regulation of autophagy, proteasome, and hnRNP-related cell stress. To conclude, Ku + myositis is morphologically characterized by myofiber necrosis, MHC-class I and II positivity, variable endomysial inflammation, and distinct protein aggregation varying from IBM and IMNM, and it can be placed in the spectrum of scleromyositis and overlap myositis. It features characteristic sarcoplasmic protein aggregation on an acquired basis being functionally associated with altered chaperone, proteasome, and autophagy function indicating that Ku + myositis exhibit aspects of an acquired inflammatory protein-aggregate myopathy.

Predictors of Progression in a Series of 81 Adult Patients Surgically Managed for an Intracranial Hemangioblastoma: Implications for the Postoperative Follow-Up.

The aim was to identify predictors of progression in a series of patients managed for an intracranial hemangioblastoma, in order to guide the postoperative follow-up modalities. The characteristics of 81 patients managed for an intracranial hemangioblastoma between January 2000 and October 2022 were retrospectively analyzed. The mean age at diagnosis was of 48 ± 16 years. Eleven (14%) patients had von Hippel-Lindau disease. The most frequent tumor location was the cerebellar hemispheres (n = 51, 65%) and 11 (14%) patients had multicentric hemangioblastomas. A gross total resection was achieved in 75 (93%) patients. Eighteen (22%) patients had a local progression, with a median progression-free survival of 56 months 95% CI [1;240]. Eleven (14%) patients had a distant progression (new hemangioblastoma and/or growth of an already known hemangioblastoma). Local progression was more frequent in younger patients (39 ± 14 years vs. 51 ± 16 years; p = 0.005), and those with von Hippel-Lindau disease (n = 8, 44% vs. n = 3, 5%, p < 0.0001), multiple cerebral locations (n = 3, 17% vs. n = 2, 3%, p = 0.02), and partial tumoral resection (n = 4, 18% vs. n = 1, 2%, p = 0.0006). Therefore, it is advisable to propose a postoperative follow-up for at least 10 years, and longer if at least one predictor of progression is present.

Mononeuritis multiplex following immune checkpoint inhibitors in malignant pleural mesothelioma.

Introduction: Mononeuritis multiplex is frequently related to vasculitic neuropathy and has been reported only sporadically as an adverse event of immune checkpoint inhibitors. Methods: Case series of three patients with mononeuritis multiplex-all with mesothelioma-identified in the databases of two French clinical networks (French Reference Center for Paraneoplastic Neurological Syndromes, Lyon; OncoNeuroTox, Paris; January 2015-October 2022) set up to collect and investigate n-irAEs on a nationwide level. Results: Three patients (male; median age 86 years; range 72-88 years) had pleural mesothelioma and received 10, 4, and 6 cycles, respectively, of first-line nivolumab plus ipilimumab combined therapy. In patient 1, the neurological symptoms involved the median nerves, and in the other two patients, there was a more diffuse distribution; the symptoms were severe (common terminology criteria for adverse events, CTCAE grade 3) in all patients. Nerve conduction studies indicated mononeuritis multiplex in all patients. Peripheral nerve biopsy demonstrated necrotizing vasculitis in patients 1 and 3 and marked IgA deposition without inflammatory lesions in patient 2. Immune checkpoint inhibitors were permanently withdrawn, and corticosteroids were administered to all patients, leading to complete symptom regression (CTCAE grade 0, patient 2) or partial improvement (CTCAE grade 2, patients 1 and 3). During steroid tapering, patient 1 experienced symptom recurrence and spreading to other nerve territories (CTCAE grade 3); he improved 3 months after rituximab and cyclophosphamide administration. Discussion: We report the occurrence of mononeuritis multiplex, a very rare adverse event of immune checkpoint inhibitors, in the three patients with mesothelioma. Clinicians must be aware of this severe, yet treatable adverse event.

H2A.Z is involved in premature aging and DSB repair initiation in muscle fibers.

Histone variants are key epigenetic players, but their functional and physiological roles remain poorly understood. Here, we show that depletion of the histone variant H2A.Z in mouse skeletal muscle causes oxidative stress, oxidation of proteins, accumulation of DNA damages, and both neuromuscular junction and mitochondria lesions that consequently lead to premature muscle aging and reduced life span. Investigation of the molecular mechanisms involved shows that H2A.Z is required to initiate DNA double strand break repair by recruiting Ku80 at DNA lesions. This is achieved via specific interactions of Ku80 vWA domain with H2A.Z. Taken as a whole, our data reveal that H2A.Z containing nucleosomes act as a molecular platform to bring together the proteins required to initiate and process DNA double strand break repair.

Inaugural dropped head syndrome and camptocormia in inflammatory myopathies: a retrospective study.

OBJECTIVES: Inaugural axial muscle involvement, defined as dropped head syndrome (DHS) and/or camptocormia (CC), is poorly described in inflammatory myopathies (IM). This study aimed to further characterize IM patients with inaugural DHS/CC, their outcome and care management. METHODS: This retrospective study included IM patients diagnosed between 2000 and 2021. The main inclusion criterion was IM revealed by axial muscle deficit (DHS/CC). RESULTS: Twenty-seven patients were included; median (IQR) age at first symptoms was 66.0 years (55.5-75.0); 21 were female (77.8%). There were nine IBM, 33.3%, nine overlap myositis (OM, 33.3%), five DM, 18.5%, two immune checkpoint inhibitor-related myositis (7.4%), one focal myositis (3.7%) and one myositis with anti-Hu antibodies (3.7%). Age at first symptoms was ≤70 years in 16 patients (59.3%), including all DM patients and 8/9 OM patients (88.9%). In this group, partial remission of the disease was obtained in 9/16 (56.3%) and complete remission in 1/16 patients (6.3%); regression of DHS/CC was achieved in 3/16 patients (18.8%). Conversely, in the group of 11 patients aged >70 years at first symptoms, there were eight IBM (72.7%). Partial remission was obtained in 5/11 patients (45.5%), the disease was stable in 6/11 patients (54.5%); no complete remission was obtained nor regression of DHS/CC. CONCLUSION: The analysis of IM patients with inaugural DHS/CC delineates two groups of patients according to the age at first symptoms in terms of clinical and outcome specificities, and proposes an adapted diagnostic and care management approach to prevent long-term complications.

Severe neuromuscular forms of glycogen storage disease type IV: Histological, clinical, biochemical, and molecular findings in a large French case series.

Glycogen storage disease type IV (GSD IV), also called Andersen disease, or amylopectinosis, is a highly heterogeneous autosomal recessive disorder caused by a glycogen branching enzyme (GBE, 1,4-alpha-glucan branching enzyme) deficiency secondary to pathogenic variants on GBE1 gene. The incidence is evaluated to 1:600 000 to 1:800 000 of live births. GBE deficiency leads to an excessive deposition of structurally abnormal, amylopectin-like glycogen in affected tissues (liver, skeletal muscle, heart, nervous system, etc.). Diagnosis is often guided by histological findings and confirmed by GBE activity deficiency and molecular studies. Severe neuromuscular forms of GSD IV are very rare and of disastrous prognosis. Identification and characterization of these forms are important for genetic counseling for further pregnancies. Here we describe clinical, histological, enzymatic, and molecular findings of 10 cases from 8 families, the largest case series reported so far, of severe neuromuscular forms of GSD IV along with a literature review. Main antenatal features are: fetal akinesia deformation sequence or arthrogryposis/joint contractures often associated with muscle atrophy, decreased fetal movement, cystic hygroma, and/or hydrops fetalis. If pregnancy is carried to term, the main clinical features observed at birth are severe hypotonia and/or muscle atrophy, with the need for mechanical ventilation, cardiomyopathy, retrognathism, and arthrogryposis. All our patients were stillborn or died within 1 month of life. In addition, we identified five novel GBE1 variants.

Spatial Transcriptomics Reveals Signatures of Histopathological Changes in Muscular Sarcoidosis.

Sarcoidosis is a multisystemic disease characterized by non-caseating granuloma infiltrating various organs. The form with symptomatic muscular involvement is called muscular sarcoidosis. The impact of immune cells composing the granuloma on the skeletal muscle is misunderstood. Here, we investigated the granuloma-skeletal muscle interactions through spatial transcriptomics on two patients affected by muscular sarcoidosis. Five major transcriptomic clusters corresponding to perigranuloma, granuloma, and three successive muscle tissue areas (proximal, intermediate, and distal) around the granuloma were identified. Analyses revealed upregulated pathways in the granuloma corresponding to the activation of T-lymphocytes and monocytes/macrophages cytokines, the upregulation of extracellular matrix signatures, and the induction of the TGF-ß signaling in the perigranuloma. A comparison between the proximal and distal muscles to the granuloma revealed an inverse correlation between the distance to the granuloma and the upregulation of cellular response to interferon-γ/α, TNF-α, IL-1,4,6, fibroblast proliferation, epithelial to mesenchymal cell transition, and the downregulation of muscle gene expression. These data shed light on the intercommunications between granulomas and the muscle tissue and provide pathophysiological mechanisms by showing that granuloma immune cells have a direct impact on proximal muscle tissue by promoting its progressive replacement by fibrosis via the expression of pro-inflammatory and profibrosing signatures. These data could possibly explain the evolution towards a state of disability for some patients.

The new missense G376V-TDP-43 variant induces late-onset distal myopathy but not amyotrophic lateral sclerosis.

TDP-43-positive inclusions in neurons are a hallmark of several neurodegenerative diseases including familial amyotrophic lateral sclerosis (fALS) caused by pathogenic TARDBP variants as well as more common non-Mendelian sporadic ALS (sALS). Here we report a G376V-TDP-43 missense variant in the C-terminal prion-like domain of the protein in two French families affected by an autosomal dominant myopathy but not fulfilling diagnostic criteria for ALS. Patients from both families presented with progressive weakness and atrophy of distal muscles, starting in their 5th-7th decade. Muscle biopsies revealed a degenerative myopathy characterized by accumulation of rimmed (autophagic) vacuoles, disruption of sarcomere integrity and severe myofibrillar disorganization. The G376 V variant altered a highly conserved amino acid residue and was absent in databases on human genome variation. Variant pathogenicity was supported by in silico analyses and functional studies. The G376 V mutant increased the formation of cytoplasmic TDP-43 condensates in cell culture models, promoted assembly into high molecular weight oligomers and aggregates in vitro, and altered morphology of TDP-43 condensates arising from phase separation. Moreover, the variant led to the formation of cytoplasmic TDP-43 condensates in patient-derived myoblasts and induced abnormal mRNA splicing in patient muscle tissue. The identification of individuals with TDP-43-related myopathy but not ALS implies that TARDBP missense variants may have more pleiotropic effects than previously anticipated and support a primary role for TDP-43 in skeletal muscle pathophysiology. We propose to include TARDBP screening in the genetic work-up of patients with late-onset distal myopathy. Further research is warranted to examine the precise pathogenic mechanisms of TARDBP variants causing either a neurodegenerative or myopathic phenotype.

Anti-SAE autoantibody in dermatomyositis: original comparative study and review of the literature.

OBJECTIVE: Among specific autoantibodies in DM, the anti-small ubiquitin-like modifier activating enzyme (SAE) antibody is rare. We aim to describe the clinical characteristics, cancer prevalence, and muscle pathology of anti-SAE-positive DM. METHODS: Patients with a diagnosis of DM and sera positive for the anti-SAE antibody were recruited from 19 centres in this retrospective observational study. The available muscular biopsies were reviewed. We conducted a comparison with anti-SAE-negative DM and a review of the literature. RESULTS: Of the patients in the study (n = 49), 84% were women. Skin involvement was typical in 96% of patients, with 10% having calcinosis, 18% ulceration and 12% necrosis; 35% presented with a widespread skin rash. Muscular disease affected 84% of patients, with mild weakness [Medical Research Council (MRC) scale 4 (3, 5)], although 39% of patients had dysphagia. Muscular biopsies showed typical DM lesions. Interstitial lung disease was found in 21% of patients, mainly with organizing pneumonia pattern, and 26% of patients showed dyspnoea. Cancer-associated myositis was diagnosed in 16% of patients and was responsible for the majority of deaths, its prevalence being five times that of the general population. IVIG therapy was administered to 51% of the patients during the course of the disease. Comparison with anti-SAE-negative DM (n = 85) showed less and milder muscle weakness (P = 0.02 and P = 0.006, respectively), lower creatinine kinase levels (P < 0.0001) and less dyspnoea (P = 0.003). CONCLUSION: Anti-SAE positive DM is a rare subgroup associated with typical skin features but a potentially diffuse rash, a mild myopathy. Interstitial lung disease defines an organizing pneumonia pattern. Cancer associated DM prevalence is five times that of the general population. TRIAL REGISTRATION: ClinicalTrials.gov, http://clinicaltrials.gov, NCT04637672.

Occurrence of focal myositis during Behçet's disease: The identification of a specific vasculitis-associated focal myopathy.

AIMS: This study aimed to report the association of focal myositis (FM) and Behçet's disease (BD) and to analyse the main characteristics of such an association. METHODS: This is a retrospective multicentre study of patients with BD and FM (BD + FM+ group) and those without FM (BD - FM+ group). Clinical, laboratory, radiological, pathological, treatment and outcome data were analysed. RESULTS: The BD + FM+ group included 10 patients; the median [interquartile range] age at BD diagnosis was 25 [16-35] years, and at FM diagnosis, it was 30 [26-42] years. The diagnosis of BD preceded FM in the majority of cases (n = 8/10). FM occurrence was associated with BD flare-ups in three cases. The creatine kinase levels remained normal or slightly increased. Histological analyses identified relatively preserved muscle tissue, associated with vasculitis (n = 5/6). All patients required treatment; most patients relapsed (n = 9/10). The BD - FM+ group included 35 patients. A comparison of the groups identified a trend towards a younger median age at diagnosis of FM among those with BD (p = 0.063) and more frequent focal muscle swelling in the BD + FM+ group (p = 0.029). The pathological analysis identified significantly less frequent muscle alterations in the BD + FM+ group (muscle fibre size heterogeneity, p = 0.021; necrosis, p = 0.007; and fibrosis, p = 0.027). BD + FM+ patients had a higher frequency of relapse (p = 0.003) and systematic treatment (p = 0.042). CONCLUSIONS: FM occurring during BD appears to be part of the systemic vasculitis process and presents as a vasculitis-associated focal myopathy with a specific clinico-histological pattern. Patients with this association require long-term follow-up and adapted management. This case series also highlights the need for research on BD diagnostic criteria in cases of FM.

Minor Salivary Gland Biopsy for the Diagnosis of Neurosarcoidosis.

INTRODUCTION: The definite diagnosis of neurosarcoidosis is challenging since it requires a compatible histology of the nervous system. When neurosarcoidosis is suspected, other systemic manifestations are investigated to confirm the diagnosis. A minor salivary gland biopsy (MSGB) is often performed since it is minimally invasive. The objective of the present study was to assess its performance for the diagnosis of neurosarcoidosis. METHODS: A retrospective single-center study included patients who underwent a MSGB in a tertiary neurological university hospital (Lyon, France) between 2015 and 2018. Clinical presentations unlikely to be compatible with neurosarcoidosis were excluded. Positive cases of neurosarcoidosis were defined as definite, probable, and possible cases, according to the latest international neurosarcoidosis diagnostic criteria from the Neurosarcoidosis Consortium Consensus Group. RESULTS: A total of 529 patients underwent a MSGB for clinical manifestations compatible with neurosarcoidosis. Among the 13 who fulfilled the criteria for neurosarcoidosis, only one had a positive MSGB. The sensitivity of MSGB was 7.7% (95% CI [0.2-36.0%]) and the specificity was 100.0% (95% CI [99.3-100%]). CONCLUSION: Considering the low sensitivity of MSGB for the diagnosis of NS, MSGB should be performed in selected indications, including a suspicion of spinal cord sarcoidosis, or when there is a strong clinical, laboratory, and radiological suspicion of NS. MSGB should rather not be performed when the chest CT-scan does not show signs of pulmonary or lymph node sarcoidosis.

Immune-Mediated Rippling Muscle Disease Associated With Thymoma and Anti-MURC/Cavin-4 Autoantibodies.

OBJECTIVES: Rippling muscle disease (RMD) is characterized by muscle stiffness, muscle hypertrophy, and rippling muscle induced by stretching or percussion. Hereditary RMD is due to sequence variants in the CAV3 and PTRF/CAVIN1 genes encoding Caveolin-3 or Cavin-1, respectively; a few series of patients with acquired autoimmune forms of RMD (iRMD) associated with AChR antibody-positive myasthenia gravis and/or thymoma have also been described. Recently, MURC/caveolae-associated protein 4 (Cavin-4) autoantibody was identified in 8 of 10 patients without thymoma, highlighting its potential both as a biomarker and as a triggering agent of this pathology. Here, we report the case of a patient with iRMD-AchR antibody negative associated with thymoma. METHODS: We suspected a paraneoplastic origin and investigated the presence of specific autoantibodies targeting muscle antigens through a combination of Western blotting and affinity purification coupled with mass spectrometry-based proteomic approaches. RESULTS: We identified circulating MURC/Cavin-4 autoantibodies and found strong similarities between histologic features of the patient's muscle and those commonly reported in caveolinopathies. Strikingly, MURC/Cavin-4 autoantibody titer strongly decreased after tumor resection and immunotherapy correlating with complete disappearance of the rippling phenotype and full patient remission. DISCUSSION: MURC/Cavin-4 autoantibodies may play a pathogenic role in paraneoplastic iRMD associated with thymoma.

Revisiting idiopathic eosinophilic myositis: towards a clinical-pathological continuum from the muscle to the fascia and skin.

OBJECTIVES: Idiopathic inflammatory myopathies are mainly defined by inflammatory infiltrates within the muscle (lymphocytes and macrophages). Eosinophil muscle infiltration has been described in idiopathic eosinophilic myositis (IEM) and rarely in EF. This study aimed to further delineate the nosological frame of idiopathic eosinophil muscle infiltration through the exhaustive analysis of IEM and EF patients. METHODS: This multicentre retrospective case series included IEM patients diagnosed between 2000 and 2022. IEM inclusion criteria were eosinophilic muscle infiltration with myositis pathological features, after the exclusion of differential diagnoses. An additional group of EF patients diagnosed between 2016 and 2022 was constituted. Inclusion criteria were an EF diagnosis and fascia thickening with inflammatory infiltrate. RESULTS: A total of 20 IEM cases and 10 EF cases were included. The median (interquartile range) age at diagnosis was 65 (49-70) years; there were 18 males. Data analysis delineated four subgroups: focal EM (FEM, n = 3), diffuse EM (DEM, n = 6), eosinophilic myofasciitis (EMF, n = 11) and EF (n = 10). FEM represented a limited and benign form of myositis. DEM cases presented objective muscle impairment with eosinophilic muscle infiltration. EMF patients presented subjective muscle impairment (myalgia, 55%), fasciitis (on histology and/or imaging), eosinophilic muscle infiltration and frequent hypereosinophilia (55%). EF patients presented myalgia (50%), muscle lesions on histology with fascia-restricted inflammatory infiltrates with (60%) or without (40%) eosinophils. CONCLUSIONS: The analysis of IEM and EF patient characteristics delineates four subgroups (FEM, DEM, EMF and EF) in terms of clinical, laboratory, imaging, pathological and outcome specificities, and proposes an adapted diagnostic and care management approach.

Mild limb girdle muscular dystrophy R9 phenotype caused by novel compound heterozygous FKRP gene mutation.

Fukutin-related protein (FKRP) mutations cause a broad spectrum of muscular dystrophies, from a relatively mild limb-girdle muscular dystrophy type 9 (LGMDR9) to severe congenital muscular dystrophy (CMD). This study aims to report two siblings belonging to a non-consanguineous Tunisian family harboring a novel compound heterozygous FKRP variant and presenting a mild LGDMR9 phenotype. For mutation screening, massive parallel sequencing was performed, followed by Sanger sequencing and multiplex ligation-dependent probe amplification (MLPA) to validate the existence of the discovered variants. The absence of alpha-dystroglycan was determined by immunohistochemistry. Brain and thigh magnetic resonance imaging (MRI) were performed to detect thigh and brain abnormalities. The two siblings had a late age at onset and clinical examination showed that the pelvic girdles had a predominantly proximal and symmetrical distribution of weakness without cardiac or respiratory involvement. They both had a modified Gardner-Medwin Walton Scale mGMWS grade of 4 and a modified Rankin Scale (mRS) score of 1. The DNA sequencing revealed a novel deletion of exons 2 and 3 in one allele and a missense mutation c.1364C > A, which has been reported to be responsible for congenital muscular dystrophy and mental retardation on the second allele. The simultaneous presence of the two variations in the two cases suggests that the variants segregate with the pathophysiology.

Novel Intronic Mutation in VMA21 Causing Severe Phenotype of X-Linked Myopathy with Excessive Autophagy-Case Report.

X-linked Myopathy with Excessive Autophagy (XMEA) is a rare autophagic vacuolar myopathy caused by mutations in the Vacuolar ATPase assembly factor VMA21 gene; onset usually occurs during childhood and rarely occurs during adulthood. We described a 22-year-old patient with XMEA, whose onset was declared at 11 through gait disorder. He had severe four-limb proximal weakness and amyotrophy, and his proximal muscle MRC score was between 2 and 3/5 in four limbs; creatine kinase levels were elevated (1385 IU/L), and electroneuromyography and muscle MRI were suggestive of myopathy. Muscle biopsy showed abnormalities typical of autophagic vacuolar myopathy. We detected a hemizygous, unreported, intronic, single-nucleotide substitution c.164-20T>A (NM_001017980.4) in intron 2 of the VMA21 gene. Fibroblasts derived from this patient displayed a reduced level of VMA21 transcripts (at 40% of normal) and protein, suggesting a pathogenicity related to an alteration of the splicing efficiency associated with an intron retention. This patient with XMEA displayed a severe phenotype (rapid weakness of upper and lower limbs) due to a new intronic variant of VMA21, related to an alteration in the splicing efficiency associated with intron retention, suggesting that phenotype severity is closely related to the residual expression of the VMA21 protein.

Skeletal muscle provides the immunological micro-milieu for specific plasma cells in anti-synthetase syndrome-associated myositis.

Anti-synthetase syndrome (ASyS)-associated myositis is a major subgroup of the idiopathic inflammatory myopathies (IIM) and is characterized by disease chronicity with musculoskeletal, dermatological and pulmonary manifestations. One of eight autoantibodies against the aminoacyl-transferase RNA synthetases (ARS) is detectable in the serum of affected patients. However, disease-specific therapeutic approaches have not yet been established.To obtain a deeper understanding of the underlying pathogenesis and to identify putative therapeutic targets, we comparatively investigated the most common forms of ASyS associated with anti-PL-7, anti-PL-12 and anti-Jo-1. Our cohort consisted of 80 ASyS patients as well as healthy controls (n = 40), diseased controls (n = 40) and non-diseased controls (n = 20). We detected a reduced extent of necrosis and regeneration in muscle biopsies from PL-12+ patients compared to Jo-1+ patients, while PL-7+ patients had higher capillary dropout in biopsies of skeletal muscle. Aside from these subtle alterations, no significant differences between ASyS subgroups were observed. Interestingly, a tissue-specific subpopulation of CD138+ plasma cells and CXCL12+/CXCL13+CD20+ B cells common to ASyS myositis were identified. These cells were localized in the endomysium associated with alkaline phosphatase+ activated mesenchymal fibroblasts and CD68+MHC-II+CD169+ macrophages. An MHC-I+ and MHC-II+ MxA negative type II interferon-driven milieu of myofiber activation, topographically restricted to the perifascicular area and the adjacent perimysium, as well as perimysial clusters of T follicular helper cells defined an extra-medullary immunological niche for plasma cells and activated B cells. Consistent with this, proteomic analyses of muscle tissues from ASyS patients demonstrated alterations in antigen processing and presentation. In-depth immunological analyses of peripheral blood supported a B-cell/plasma-cell-driven pathology with a shift towards immature B cells, an increase of B-cell-related cytokines and chemokines, and activation of the complement system. We hypothesize that a B-cell-driven pathology with the presence and persistence of a specific subtype of plasma cells in the skeletal muscle is crucially involved in the self-perpetuating chronicity of ASyS myositis. This work provides the conceptual framework for the application of plasma-cell-targeting therapies in ASyS myositis.

Clinical and pathological impact of an optimal assessment of brain invasion for grade 2 meningioma diagnosis: lessons from a series of 291 cases.

Brain invasion has not been recognized as a standalone criterion for atypical meningioma by the WHO classification until 2016. Since the 2007 edition suggested that meningiomas harboring brain invasion could be classified as grade 2, brain invasion study was progressively strengthened in our center, based on a strong collaboration between neurosurgeons and neuropathologists regarding sample orientation and examination. Practice changes were considered homogeneous enough in 2011. The aim of the present study was to evaluate the impact of gross practice change on the clinical and pathological characteristics of intracranial meningiomas classified as grade 2.The characteristics of consecutive patients with a grade 2 meningioma surgically managed before (1998-2005, n = 125, group A) and after (2011-2014, n = 166, group B) practices changed were retrospectively reviewed.Sociodemographical and clinical parameters were comparable in groups A and B, and the median age was 62 years in both groups (p = 0.18). The 5-year recurrence rates (23.2% vs 29.5%, p = 0.23) were similar. In group A, brain invasion was present in 48/125 (38.4%) cases and was more frequent than in group B (14/166, 8.4%, p < 0.001). In group A, 33 (26.4%) meningiomas were classified as grade 2 solely based on brain invasion (group ASBI), and 92 harbored other grade 2 criteria (group AOCA). Group ASBI meningiomas had a similar median progression-free survival compared to groups AOCA (68 vs 80 months, p = 0.24) and to AOCA and B pooled together (n = 258, 68 vs 90 months, p = 0.42).An accurate assessment of brain invasion is mandatory as brain invasion is a strong predictor of meningioma progression.