MYH7-related myopathies: Clinical, histopathological and imaging findings in a cohort of Italian patients

Abstracts / Neuromuscular Disorders 25 (2015) S184–S316 and turnover. Elucidating the roles of these fragments is important for understanding the structure and function of the M-line and the whole sarcomeric machinery. http://dx.doi.org/10.1016/j.nmd.2015.06.340

G.P.317 Oculopharyngodistal myopathy in a Korean family J. Shin *, D. Kim, K. Lee, J. Sung Seoul National University Hospital, Neurology, Seoul, South Korea Even now, there is no consensus whether Oculopharyngodistal myopathy (OPDM) is an unequivocal muscle disease entity or not. OPDM is a rare muscle disease that is inherited in autosomal dominant or autosomal recessive pattern. Clinical features of OPDM are progressive ophthalmoplegia, facial diplegia, dysphagia, and distal muscle weakness; therefore it is often confused with other muscle disease, such as oculopharyngeal muscular dystrophy (OPMD), myotonic dystrophy and distal myopathies. Here we report the Korean family who had typical OPDM characteristics. A 35-year-old man visited the hospital due to progressive bulbar weakness, ptosis and limbs weakness. At the age of 20, he started to detect voice change, weight loss and swallowing difficulty. And then, progressive limb weakness and atrophy were noted, distal dominantly. His sister who is 2 years younger than him also has a clinical history similar to him. His farther has been in chronic quadriplegic state following traumatic spinal cord injury of cervical lesion from 4 years ago. Neurologic examination showed horizontal gaze paresis, facial diplegia and weakness of bilateral soft palate elevation. Also there were diffuse weakness and atrophies of limbs, more prominent in distal part. There was no percussion myotonia in thenar and tongue muscles. Examination findings were similar in brother and sister, but her symptoms were mild. Serum creatine kinase level was highly increased (1336/ IU). The electrophysiologic studies revealed myopathic pattern. Interestingly, myotonic discharges were seen in his sister’s electromyography. Genetic studies of DMPK and PABPN 1 were normal. The genetic defect underlying OPDM is not known. Also, there is clinical overlap between OPDM and other myopathies, especially OPMD. In patients with OPMD, symptoms developed in the middle 40s to early 50s, and it is confirmed genetically by commercially available test. Therefore, OPDM can be differentiated from OPMD, and is another muscle disease. http://dx.doi.org/10.1016/j.nmd.2015.06.341

G.P.318 Longitudinal study for GNE gene (ClinBio-GNE) T. Gidaro *, D. Duchene, G. Ollivier, V. Decostre, J.Y. Hogrel, P. Carlier, A. Behin, L. Servais Institut-de Myologie, Paris, France The aim of ClinBio-GNE study is to search for new clinical and biological markers usable as Outcome Measures in clinical trials in HIBM. HIBM is a genetic autosomal recessive neuromuscular disorder due to mutations of GNE gene. Today there are still no specific and sensitive Outcome Measures identified for HIBM patients. Presently, treatment trials for HIBM are based on ManNAc therapy. A Phase 2 study has been completed and a phase 3 will start in the coming months. An Ultragenyx-funded natural history study of HIBM patients has started in several centers including Institute of Myology in Paris where the present project (ClinBio GNE) is conducted as ancillary study. ClinBio-GNE is a 3 year prospective, descriptive and longitudinal study in 15 HIBM patients and age-matched controls subjects. The following tests will be performed at inclusion day and at the following visits scheduled every year: Handgrip and key pinch strength as well as hand and finger endurance test assessed by the MoviPlate; muscular upper and lower limbs NMR; Neprilysin enzymatic activity. Nine GNE patients aged between 20 and 65 years have been included so far. Seven patients are ambulatory. A significant correlation

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between muscular strength (MyoGrip, MyoPinch) and functional activity (MoviPlate) of distal upper limbs was found. Moreover, MyoPinch presents a greater resolution so that key pinch strength of the weakest patients can be measured while it is undetectable with B&L gauges. Serum neprilysin enzymatic activity will be studied for sialylation biomarker. Furthermore, NMR muscular imaging pattern could provide additional diagnostic signs useful in the initial clinical assessment of patients with possible GNE myopathy also with atypical presentation. ClinBio-GNE study could improve knowledge of the disease and lead to specific and sensitive outcome measures for upcoming therapeutic trials. http://dx.doi.org/10.1016/j.nmd.2015.06.342

G.P.319 GNE myopathy worldwide epidemiology based on the patient self-reported registry O. Pogoryelova *,1, P. Cammish 1, A. Skrinar 2, S. Rao 2, H. Lochmüller 1, E. Kakis 2 1 Newcastle University, The John Walton Muscular Dystrophy Research Centre, Newcastle upon Tyne, UK; 2 Ultragenyx Pharmaceutical Inc., Novato, California, USA GNE myopathy (also known as HIBM) is an ultra-rare autosomal recessive distal myopathy. GNE myopathy is caused by mutations in the GNE gene resulting in reduced sialic acid synthesis. Clinical presentation varies from asymptomatic carriers to severely debilitating forms. The aim of the analysis is to describe worldwide epidemiology, presentation and course of the disease based upon the data obtained from the registry. The GNE registry is part of a disease monitoring program which also includes a hospital based/physician reported natural history study. The registry component is designed as a global online patient self-reported system. It was launched in March 2014, with 160 patients currently registered, of which 116 (72.5%) have completed questionnaires. European residents represent over 35% of those registered, followed by Middle Eastern and North Americans (19% each). Patients from 21 countries are represented in the registry. Mean age of onset is 29 years, with the earliest onset at 5 years, described as “slow runner”, and oldest at 45 years. Time between the onset and use of wheelchair on average is 13 years. Ambulant patients comprise 61.4% of the study cohort; 18.2% have limited ambulation and 20.4% are non-ambulant. A range of assistive devices are in use, with ankle orthotics being most common (35%). Most mutations (26/29) are missense, the rest (3/29) are deletions. International registry and patient self-reported data provided valuable epidemiological information on an ultra-rare disease, previously only described in a country specific manner. It is a useful tool in helping facilitate translational research and better understanding the disease based on worldwide disease specific data. http://dx.doi.org/10.1016/j.nmd.2015.06.343

G.P.320 MYH7-related myopathies: Clinical, histopathological and imaging findings in a cohort of Italian patients C. Fiorillo *,1, M. Savarese 2, G. Astrea 3, D. Cassandrini 3, L. Ruggiero 4, M. Fanin 5, L. Vercelli 6, A. D’Amico 7, M. Pane 8, G. Tasca 7, M. Morandi 9, E. Pegoraro 5, L. Santoro 4, E. Mercuri 8, M. Mora 9, E. Bertini 7, C. Minetti 1, F. Santorelli 3, V. Nigro 2, C. Bruno 10 1 Istituto G.Gaslini, Pediatric Neurology and Muscular Disorders, Genoa, Italy; 2 Telethon Institute of Genetics and Medicine, Naples, Italy; 3 IRCCS Stella Maris, Neuromuscular and Molecular Medicine Unit, Pisa, Italy; 4 University Federico II, Department of Neuroscience, Naples, Italy; 5 University of Padova, Department of Neuroscience, Padova, Italy; 6 Ospedale Molinette, Malattie Neuromuscolari Dipartimento di Neuroscien, Turin, Italy; 7 Ospedale Pediatrico bambino Gesu, UOC Malattie Neuromuscolare e Neurodegenerative, Rome, Italy; 8 Policlinico Gemelli, Università Cattolica del Sacro Cuore, Neuropsichiatria Infantile, Rome, Italy; 9 Istituto Nazionale

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Neurologico “C.Besta”, Department of Diagnostic and Experimental Research, Milan, Italy; 10 Istituto G.Gaslini, Pediatric Neurology and Muscular Disorders, Genoa – Congenital Myopathy Network, Italy Myosin 7 gene (MYH7) encodes slow/beta-cardiac myosin heavy chain, a class II myosin expressed primarily in the heart, and also in skeletal muscles. MYH7 defect was typically associated with distinct muscle disorders on the basis of site of mutations and the following clinical phenotype have been shown: Familial Hypertrophic Cardiomyopathy (FHCM) associated with mutations in the globular head of the protein, Laing Distal Myopathy (LDM) with mutations in the proximal rod, and Myosin Storage Myopathy (MSM) with defect in the distal rod. Recently the number of cases presenting mutations in MYH7 has increased significantly, adding further phenotypes to the list and making more complex the differential diagnosis on a clinical ground only. In this work we describe 16 cases, 8 familial, carrying reported or new mutations in MYH7. Patients displayed a broad phenotype including atypical picture, such as infantile dropped head and “bent” spine, which cannot be classified in previously described clinical categories. Patients with overlapping manifestations were also identified. Half of patients had congenital or early infantile weakness with predominant distal involvement of upper and lower limbs. Patients with later onset presentation had a prevalent proximal weakness. Scoliosis, calf hypertrophy and nasal speech were common findings. Serum CK levels were normal or mildly elevated (<1000 U/L). Six of 16 patients manifested cardiac involvement including non-compacted myocardium even at early onset. Muscle biopsy was consistent with minicores myopathy in 8 cases and, in one case, a picture of fiber-type-disproportion (FTD) was noted. Muscle MRI was meaningful in delineating a shared pattern of selective damage of glutei and tibialis anterior muscles, with relative sparing of quadriceps. In most severe cases, involvement of gastrocnemii was also present. This work adds to the genotype-phenotype correlation of mutations in MYH7, confirming the complexity of this muscle disorder. http://dx.doi.org/10.1016/j.nmd.2015.06.344

G.P.321 Analysis of the pathogenesis of vocal cord and pharyngeal weakness with distal myopathy S. Yamashita *,1, T. Nishikami 1, N. Tawara 1, T. Doki 1, Y. Nakajo 1, Y. Matsuo 1, Y. Yonemochi 1, M. Nagai 2, Y. Maeda 1, Y. Ando 1 1 Kumamoto University, Graduate School of Medical Sciences, Neurology, Kumamoto, Japan; 2 Kitasato University School of Medicine, Neuroregenerative Medicine, Sagamihara, Japan Vocal cord and pharyngeal weakness with distal myopathy (VCPDM) is an adult-onset, autosomal-dominant distal myopathy, frequently associated with dysphagia and dysarthria. Recently, a missense mutation in the matrin-3 (MATR3) gene was identified as a causative gene for VCPDM. The aim of our study is to examine biopsied samples of the skeletal muscles histopathologically, and then analyze the effect of mutant MATR3 on primary myoblast cells. First, we performed immunohistochemical analysis on the biopsied samples from skeletal muscles of patients with VCPDM and disease control, using anti-MATR3, p62, TDP-43 and ubiquitin antibodies. Next, we transduced wild-type or mutant S85C MATR3, or siRNA for MATR3 into primary myoblast cells, and investigated subcellular localization, cell viability, effect on TDP-43 expression and DNA double strand break in these cells. Finally, we inoculated adeno-associated viral (AAV) vectors expressing wildtype or mutant S85C MATR3 into the skeletal muscles of C57BL/6 mice, and assessed the effect on subcellular localization of MATR3 in the inoculated muscle fibers. In the skeletal muscles of patients with VCPDM, some myonuclei lost immunoreactivity for MATR3 and degenerative myofibers showed sarcoplasmic aggregation of p62, TDP-43, and ubiquitin. In the primary myoblast cells, wild-type MATR3 localized in the nuclei, whereas mutant S85C MATR3 localized ectopically in the cytoplasm and reduced cell viability. MATR3 knockdown also reduced cell viability and resulted in an increase of γH2AX and phosphorylated TDP-43-expressinng cells. Mutant MATR3 might

cause DNA damage due to its intranuclear loss-of-function, and then gain the toxicity as a TDP-43 proteinopathy due to ectopic intrasarcoplasmic localization of MATR3 accompanied by TDP-43 phosphorylation. Animal models such as mutant MATR3-expressing transgenic mice or mice inoculated with AAV vector expressing mutant MATR3 would be helpful for analyzing the pathogenesis of VCPDM. http://dx.doi.org/10.1016/j.nmd.2015.06.345

G.P.322 Unique myopathy presenting in adulthood with proximal muscle weakness and respiratory insufficiency N. Goyal *, M. Waldrop, T. Mozaffar University of California, Neurology, Irvine, USA Adult onset progressive proximal muscle weakness with early respiratory insufficiency suggests a limited differential after ruling out disorders of motor neuron, neuromuscular junction, and nerve. Late-onset Pompe and a number of dystrophies are considered; however, centronuclear myopathies (while known to have a broad phenotype) do not commonly present in adults. We present a case of adult-onset proximal muscle weakness featuring prominent scapular winging and respiratory insufficiency with a mutation in CCDC78, typically associated with a congenital myopathy. A 70-year-old female presents with 10 years of progressive proximal arm weakness, scapular winging and 2 years of shortness of breath requiring BiPAP. Her examination revealed: significant use of accessory muscles while seated, marked bilateral scapular winging with striking paraspinal muscle atrophy. Severe restriction in shoulder abduction was noted with moderate weakness in other proximal limb muscles. Strength of her oculobulbar muscles, reflexes, sensation and gait were intact. Her evaluation included: PFTs that showed FVC 0.75 L, 29% predicted. EMG: non-irritable myopathy. Pompe and FSHD genetic testing: negative. Biceps muscle biopsy: type 2 fiber atrophy, no central nuclei or cores. Myopathy NextGen DNA panel: positive for dominant CCDC78 single base pair mutation (c.1133 + 1G > C) on chromosome 16, thought to be pathogenic. Prior known disease-causing mutations in CCDC78 are in exon 2 and present as early-onset distal myopathy. Reported clinical features are neonatal hypotonia, falls and mild cognitive impairment with preserved oculobulbar, cardiac and respiratory function. Rare adult onset cases have been reported but with predominantly distal symptoms. Our patient has a CCDC78 mutation in exon 11 with a unique phenotype; she presents in adulthood and has a symmetric proximal myopathy (rather than distal) with normal cognition and impaired respiratory function. http://dx.doi.org/10.1016/j.nmd.2015.06.346

G.P.323 Targeted next-generation sequencing reveals novel TTN mutations causing recessive distal titinopathy A. Evilä *,1, S. Penttilä 2, P. Hackman 1, B. Udd 2 1 Folkhälsan Institute of Genetics and Department of Medical Genetics, Haartman Institute, University of Helsinki, Helsinki, Finland; 2 Neuromuscular Research Center, University of Tampere and Tampere University Hospital, Tampere, Finland Tibial muscular dystrophy (TMD) is the first described human titinopathy. It is caused by mutations in the last two exons, Mex5 and Mex6, of titin gene (TTN). The first reported TMD mutations were dominant and the Finnish founder mutation, an 11-bp insertion/deletion in Mex6, caused a severe earlyonset limb-girdle muscular dystrophy 2J (LGMD2J) when homozygous. Later we reported that not all TMD mutations cause LGMD when homozygous, but some rather cause a more severe TMD. We have now performed a targeted next-generation sequencing assay of myopathy related genes on six families with recessive distal titinopathy. Two novel TMD mutations in TTN were identified, which both seem to be recessive. Three of the families, Italian, Bosnian and Iranian, had a novel nonsense TMD mutation in TTN Mex5 in