A novel DNAJB6 mutation causing variable phenotypic expression: From distal myopathy to limb girdle muscular dystrophy

Abstracts 2016 / Neuromuscular Disorders 26 (2016) S88–S212 muscle to determine metabolic changes in a subgroup of patients. The strength assessments detected statistically significant change over a year in multiple muscle groups. MMT showed significant change with shoulder abduction, elbow flexion biceps, wrist flexion, hip adduction and hip flexion. HHD also indicated significant change for elbow flexion biceps, hip adduction, elbow flexion brachioradialis, grip, pinch, knee extension, knee flexion and ankle PF knee bent. The functional tests, MFM and NSAA both highlighted statistically significant change as did stacking cans and writing on the Jebsen. All timed tests were statistically sensitive to change over a year. MRI fat fraction showed significant change over a year in both the thigh and calf muscles. In the opposite, water T2 did not change significantly. These data allow exploration of relationships between physiotherapy data and MRI with respect to how these potential outcome measures perform in the dysferlin population. http://dx.doi.org/10.1016/j.nmd.2016.06.029

P.8 Development of a robust disease specific functional measure suitable for trials in ambulant and non-ambulant individuals with dysferlinopathy M. James 1, A. Mayhew 1, M. Eagle 1, U. Moore 1, R. Muni Lofra 1, K. Bettinson 1, E. Harris 1, K. Bushby 1, The Jain Consortium 2 1 John Walton Muscular Dystrophy Research Centre, Newcastle Upon Tyne, UK; 2 Jain Foundation, Seattle, WA, USA An aim of the COS study is to establish robust functional rating scales for use in ambulant and non-ambulant patients with dysferlinopathy. Functional outcome measures were reviewed for suitability and robustness. Functional ability, as measured by the motor function measure (MFM) and North Star Ambulatory Assessment for Dysferlinopathy (NSAA), was reviewed using modern psychometric methods (Rumm 2030). Analysis of 156 patients, with between one and four visits (n = 199), investigated the ability of the individual items of both scales to measure the underlying construct of the scale. It also reviewed the strength of combining the scales to create a robust scale suitable for all levels of ability. We show that the NSAA measures stronger patients more effectively, with some items from the MFM contributing to better measurement of weaker and non-ambulant individuals. Distal items in the MFM were not useful in measuring this population and appear to confuse the single construct of motor performance. A revised scale, with items reordered to reduce fatigue, was produced with simplified scoring of 0, 1 and 2 per item. This scale was subsequently tested in 100+ individuals using the same modern psychometrics methods as before. This revision – North Star Assessment for Dysferlinopathy (NSAD) was shown to be psychometrically robust and clinically meaningful. http://dx.doi.org/10.1016/j.nmd.2016.06.030

P.9 HyperCKemia and myalgia are the most common presentation of anoctamin-5 (ANO5) related myopathy in French patients C. Papadopoulos 1, P. Laforêt 1, J. Nectoux 2, T. Stojkovic 1, K. Wahbi 3,4, R. Carlier 5, P. Carlier 1, S. Leonard-Louis 1, F. Leturcq 2, B. Eymard 1, A. Behin 1 1 AP-HP, Pitié-Salpêtrière Hospital, Myology Institute, Paris, France; 2 APHP, Service de Biochimie et Génétique Moléculaire, Cochin Hospital, Paris, France; 3 AP-HP, Pitié-Salpêtrière Hospital, Myology Institute, Paris, France; 4 AP-HP, Department of Cardiology, Cochin Hospital, Paris, France; 5 APHP, Raymond Poincaré Hospital, Service orthopédie, Garches, France Beside limb-girdle muscular dystrophy 2L (LGMD2L) and adult-onset distal Miyoshi-like myopathy (MMD3), many patients with ANO5 mutations present with asymptomatic hyperCKemia and exercise intolerance. We describe here the frequency and presentation of such patients among the 38 genetically proven cases of ANO5-related myopathy diagnosed in Paris. We reviewed the data from patients without muscle weakness on their first examination and subsequently compared them with data from patients with permanent weakness.

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Twenty patients (14 males) presented without muscle weakness (12 of them with exercise intolerance). Age at symptom onset or discovery of hyperCKemia ranged from 10 to 48 years (mean 26.6). CK levels ranged from 200 to 40,000 U/L, varying widely between measurements in each single patient. Electromyography showed a myopathic pattern in 5 patients, mild cardiac involvement was observed in 2, while muscle imaging showed posterior calf degeneration in 10. Muscle biopsy, performed on 18 patients, revealed myopathic or dystrophic features in 13. Sixteen are still free of muscle weakness after a follow-up period ranging from one to sixteen years (mean = 4.8). These results were similar to those found in patients with muscle weakness. We found no genotype–phenotype correlation between the different patterns of the disease and the various mutations found in the French patients, in particular the c.191dupA duplication. In conclusion, ANO5-related myopathy manifests as a long-standing history of asymptomatic hyperCKemia or exercise intolerance in at least one half of French patients. Most of these patients will not develop muscle weakness for a long period. Genetic diagnosis of ANO5-related muscular dystrophy should be considered in cases of unexplained significant hyperCKemia, with or without exercise intolerance, especially if fatty replacement is observed through muscle imaging at the calf level. http://dx.doi.org/10.1016/j.nmd.2016.06.031

P.10 A histologically diagnosed case with limb-girdle muscular dystrophy type 1A: The youngest case in the literature G. Diniz 1, S. Edizer 2, G. Gurbuz 2, A. Unalp 2 1 Tepecik Research Hospital Neuromuscular Disease Centre, Izmir, Turkey; 2 Dr. Behcet Uz Children’s Hospital, Izmir, Turkey Myofibrillar titin-like protein (myotilin) is a 55.3 kDa protein that in humans is encoded by the MYOT gene. Myotilin is a protein composed of 496 amino acids and it was originally identified as a novel alpha-actinin binding partner with two Ig-like domains that localized to the Z-disc. Myotilin expression in human tissues is mainly restricted to striated muscles and nerves. In muscles, myotilin is predominantly found within the Z-discs. Myotilin is a structural protein that, along with titin and alpha-actinin gives structural integrity to sarcomeres at Z-discs in striated muscle. It was demonstrated that myotilin stabilizes F-actin by slowing down the disassembly rate. A nine-yearold girl was referred to our clinic with frequent falls and fatigue complaints. In muscle biopsy, dystrophic and/or myopathic findings were observed. Immunohistochemically there was diffuse loss of cytoplasmic myothilin expression. This finding was in compliance with LGMD type 1A. It has been previously demonstrated that myotilin is mutated in various forms of muscular dystrophy; such as Limb-girdle muscular dystrophy type 1A (LGMD1A), myofibrillar myopathy (MFM), spheroid body myopathy and distal myopathy. All of them are present during the adulthood. The mechanism underlying the pathology is still under investigation. The presented case is interesting because LGMD 1A is generally presented during adulthood. To our knowledge, this is the youngest case of LGMD-1A in the literature. http://dx.doi.org/10.1016/j.nmd.2016.06.032

P.11 A novel DNAJB6 mutation causing variable phenotypic expression: From distal myopathy to limb girdle muscular dystrophy T. Stojkovic 1, A. Bedat-Millet 2, F. Chapon 3, E. Malfatti 4, N. Romero 4, G. Brochier 4, A. Laquerriere 2, S. Penttila 5, P. Jonson 6, J. Palmio 5, P. Hackman 6, B. Udd 5, B. Eymard 1 1 G-H Pitié-Salpêtrière, Paris, France; 2 CHU de Rouen, Rouen, France; 3 CHU de Caen, Caen, France; 4 Institut de Myologie, Paris, France; 5 University of Tampere, Tampere, Finland; 6 University of Helsinki, Helsinki, Finland Myofibrillar myopathies (MFM) are a heterogeneous group of inherited neuromuscular disorders characterized by myofibrillar dissolution and

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Abstracts 2016 / Neuromuscular Disorders 26 (2016) S88–S212

accumulation of aggregates. The clinical phenotypes of MFM encompass distal myopathies, limb girdle dystrophies, scapuloperoneal syndrome, rigid sine and neuropathy, and cardiomyopathies. Mutations of DNAJB6 gene have been associated with autosomal dominant limb girdle dystrophy and recently with a distal myopathy. We present the clinical, histopathological and muscle imaging features of 2 unrelated autosomal dominant DNAJB6 families, with a novel mutation. The first family is originated from Normandy. Four members of this family present a distal weakness of the lower limb, with onset of the disease between 40 and 60 years of age. They present initially asymmetric weakness and wasting either of the anterior or posterior compartments of the legs. The older case (90 years old) had a distal and proximal weakness of the four limbs and is wheelchair bound. The remaining members of the family are still fully ambulant. The second family is also originated from Normandy. Three members present a proximal weakness predominantly in the lower limbs, with asymmetric involvement in one of them. The onset of the disease ranged from 38 to 55 years of age. All are still ambulant, although one of them aged of 66 years, needed a cane to walk. Cardiac or respiratory involvement was noted detected. Electromyography showed a myogenic pattern. CK were normal or slightly elevated. Muscle biopsy showed in the first family an extensive vacuoles and myofibrillar aggregates, while multiple rimmed vacuoles and cytoplasmic bodies were observed in the second family. Target exome gene panel revealed a novel p.Asn95Leu substitution in the 2 families. This study confirms the causative role of DNAJB6 in distal and limb-girdle muscular dystrophy and the variable histopathological features ranging from rimmed vacuolar pathology to myofibrillar aggregates. http://dx.doi.org/10.1016/j.nmd.2016.06.033

P.12 Limb-girdle muscular dystrophy 1 G (LGMD1G) with numerous rimmed vacuoles due to a defect in the RNA-binding protein HNRNPDL – Report of an Argentinian family of Italian ancestry X. Lornage 1, N. Romero 2, J. Laporte 3, A. Dubrovsky 4, F. Barroso 5, M. Saccoliti 6, A. Taratuto 7 1 Institut de Génétique et de Biologie Moléculaire et Cellulaire (IGBMC), Illkirch, France; 2 Pierre and Marie Curie University, PitieSalpêtrière University Hospital Group, Paris, France; 3 Institut de Génétique et de Biologie Moléculaire et Cellulaire (IGBMC), Illkirch, France; 4 Institute.Favaloro Foundation, Buenos Aires, Argentina; 5 Institute of Neurological Diseases Raul Carrea,FLENI, Buenos Aires, Argentina; 6 Durand Hospital, Buenos Aires, Argentina; 7 Institute of Neurological Diseases Raul Carrea, FLENI and Garrahan’s National Pediatric Hospital, Buenos Aires, Argentina We report a large family living in Argentina with a history of dominant limb-girdle muscular dystrophy for three generations. Members of the first generation migrated from Italy and arrived to Argentina through Uruguay. From a total of 40 members, 9 were clinically affected: 3 in the first, 5 in the second and 1 in the third generation. All affected members had an adult disease-onset, beginning after the third decade and characterized by predominantly proximal weakness and frequent falls. At a later disease-stage, they developed progressive toe and finger flexion limitation. Scapular winging and foot, legs and hand cramps were present in several family members. Early cataracts were reported in at least three affected individuals (one female and two males). Reduced vital capacity and ventilatory insufficiency were reported in two patients. Quadriceps muscle biopsy performed in 2 affected siblings (1 female and 1 male) of the second generation and one male of the third, showed myopathic and neurogenic changes, numerous rimmed vacuoles and cytoplasmic bodies. Ultrastructural analysis of the most affected muscle showed autophagic changes, Z band streaming, myofibrillar dissolution, some granular material as well as filamentous accumulation, suggestive of a myofibrillar myopathy. Exome-sequencing of 3 family members of the second generation and one of the third, revealed a missense variation in a well conserved amino-acid in the gene coding for the heterogeneous nuclear ribonucleoprotein D like (HNRNPDL). The variation segregated with the disease within the family. This result is in accordance with the previous

published data in 2014, who described the same mutation and a mutation affecting the same amino-acid in two families with similar phenotypes. Our study confirms the crucial role of HNRNPDL for muscle function and expands the phenotypes description for LGMD1G. http://dx.doi.org/10.1016/j.nmd.2016.06.034

P.13 Proteasomal proteolysis is indispensable for the maintenance of skeletal muscle and muscle stem cells N. Suzuki 1, Y. Kitajima 2, Y. Tashiro 3, H. Ono 1, R. Ando 1, S. Osana 1, A. Nunomiya 1, R. Nagatomi 1, R. Takahashi 3, M. Aoki 1 1 Tohoku University, Sendai, Japan; 2 Nagasaki University, Nagasaki, Japan; 3 Kyoto University, Kyoto, Japan The ubiquitin–proteasome and autophagy–lysosome pathways are the two major routes of protein and organelle clearance. The role of the proteasome pathway in mammalian muscle has not been examined in vivo. Previously, we reported that the conditional knockout of a crucial proteasomal gene, Rpt3 (also known as psmc4), in motor neurons caused locomotor dysfunction that was accompanied by progressive motor neuron loss and gliosis in mice. In this study, we report that the muscle-specific deletion of Rpt3 resulted in profound muscle growth defects and a decrease in force production in mice. Specifically, developing muscles in conditional Rpt3-knockout animals showed dysregulated proteasomal activity. The autophagy pathway was upregulated, but the process of autophagosome formation was impaired. A microscopic analysis revealed the accumulation of basophilic inclusions and disorganization of the sarcomeres in young adult mice. Our results suggest that appropriate proteasomal activity is important for muscle growth and for maintaining myofiber integrity in collaboration with autophagy pathways. The deletion of a component of the proteasome complex contributed to myofiber degeneration and weakness in muscle disorders that are characterized by the accumulation of abnormal inclusions. We are now examining muscle stem cell specific deletion of Rpt3 to elucidate the functional role of proteasome system in the maintenance of stem cells. http://dx.doi.org/10.1016/j.nmd.2016.06.035

P.14 BMS-986089 is a high affinity anti-myostatin adnectin that increases muscle volume in three preclinical species M. Madireddi 1, H. Malone 2, D. Kukral 2, A. Chimalakonda 1, A. Kozhich 2, Y. Xiling 2, J. Swain 3, A. Yamniuk 3, M. Ahlijanian 4 1 Bristol-Myers Squibb, Hopwell, USA; 2 Bristol-Myers Squibb, Lawrenceville, USA; 3 Bristol-Myers Squibb, Waltham, USA; 4 Bristol-Myers Squibb, Wallingford, USA Myostatin is a negative regulator of skeletal muscle. Genetic ablation or pharmacologic inhibition of myostatin results in increased skeletal muscle size in several species including human. Reducing myostatin is a potential therapeutic approach for skeletal muscle diseases such as Duchenne’s muscular dystrophy (DMD). BMS-986089 is an anti-myostatin adnectin (engineered scaffold based on the 10th fibronectin type III domain) that exhibits high affinity for myostatin (Kd = 0.17–0.45 nM) and inhibits myostatin and GDF-11 second messenger signaling in cells (IC50s = 0.06–1 nM and 0.09–0.7 nM, respectively). In male SCID mice (to avoid immunogenic responses), four weekly sub-cutaneous (SC) doses (0.1–100 mpk) of BMS-986089 produced dose- and time-dependent increases in lower limb muscle volume (MRI) of up to approximately 30%. In male rats, a single SC administration of BMS-98089 (0.3−25 mpk) produced time- and dose-dependent increases in lower limb muscle volume that reached a maximum of up to 16%, 15 days post-dose. In male cynomolgus monkeys, four weekly SC doses (0.3–25 mpk) of BMS986089 produced dose- and time-dependent increases in lower limb muscle volume of up to approximately 5%. In each study serum free myostatin was