UNCORRECTED PROOF Conclusion: In this single-center, retrospective study, using the same PEG technique and same physicians, PEG appeared to be as safe and effective for patients with DMD as has been observed for patients with ALS. doi:10.1016/j.jns.2017.08.763 736 WCN17-1161 SHIFT 1 - NEUROMUSCULAR DISORDERS The role of perlecan in nnos mediated mechanotransduction in skeletal muscle E. Arikawa-Hirasawa, S. Nakada, Y. Yamashita, N. Hattori. Juntendo University, Graduate School of Medicine, Tokyo, Japan Background: Perlecan is an extracellular matrix molecule anchored to sarcolemma via a dystrophin-glycoprotein complex (DGC) in skeletal muscle. We reported perlecan-deficient mice have a tolerance to muscle atrophy, suggesting that perlecan may negatively regulate skeletal muscle mass. Suzuki et al. reported that dislocation of sarcolemma-localized neuronal nitric oxide synthase (nNOS) to the cytosol is an essential trigger for protein-degradation signaling activation and skeletal muscle atrophy. From these studies, we hypothesized that perlecan regulates nNOS dislocation and activate protein-degradation signaling during skeletal muscle atrophy. Objective: Identifying the role of perlecan in nNOS-mediated mechanotransduction, which activates FoxO signaling and protein degradation. Patients and Methods/Material and Methods: Perlecan deficient muscle in a mouse model (Hspg2-/-;Tg) and wild type control mice (WT;Tg) were used in this study. Mice had unilateral sciatic nerve resection surgery performed, and the gastrocnemius muscles were denervated. Results: Four days and 14 days after surgery, gastrocnemius muscle atrophy was significantly reduced in Hspg2-/-;TG compared to WT;Tg mice. Western blotting using cytosolic fraction revealed that the cytosolic nNOS content increased following denervation in WT;Tg mice, but not in Hspg2 -/-;Tg. Moreover, atrophy-related proteins, FoxO1a, atrogin-1, and poly-ubiquitinated proteins were increased in denervated muscle of WT;Tg mice, but these increases were inhibited in Hspg2-/-;Tg mice. Conclusion: These findings suggest that perlecan plays a role in activating FoxO signaling and protein degradation by promoting nNOS dislocation during the mechanical stress reduction. doi:10.1016/j.jns.2017.08.764 737 WCN17-1634 SHIFT 1 - NEUROMUSCULAR DISORDERS Analysis of the risk of cancer among myositis patients without anti-TIF1-γ OR –HMGCR antibodies A. Unuma a , M. Kadoya b , A. Hida c , K. Taira a , N. Uchio a , C. Ikenaga a , A. Kubota a , S. Tsuji a , J. Shimizu a . a Graduate School of Medicine, - The University of Tokyo, Neurology, Tokyo, Japan; b National Defense Medical College, Neurology and Anti-aging Medicine, Saitama, Japan; c Center Hospital of the National Center for Global Health and Medicine, Neurology, Tokyo, Japan Background: It is well known that the risk of cancer is elevated in myositis patients. We previously reported that both anti-TIF1-γ and -HMGCR antibodies (Abs) had close relations to cancer in myositis patients. However, whether the elevated risk of cancer is entirely attributable to these two antibodies remains unclear. Objective: To know the risk of cancer among myositis patients without anti-TIF1-γ or -HMGCR Abs. Patients and Methods/Material and Methods: We retrospectively studied the clinical courses in 158 patients with biopsy-proven myositis diagnosed in our hospital between 2000 and 2016, excluding patients with anti-TIF1-γ/-HMGCR Abs and inclusion body myositis. We defined cancer associated myositis (CAM) as myositis with cancer detected within 3 years of myositis diagnosis. The risk of cancer was evaluated using standardized incidence ratio (SIR), the ratio of the observed to expected number of cancer in the general population. Results: Among 158 patients, 18 patients were diagnosed as CAM. The SIR of cancers from the diagnosis of myositis to after 3 months was 17.0 (95%CI 4.6-43.5), and from the diagnosis to after 3 years was 5.0 (95%CI 2.5-9.0). On the other hand, the SIR from 3 months to 3 years was 0.58 (95%CI 0.2-1.2). Conclusion: Our data suggests that the risk of cancer within three years of myositis diagnosis is also higher in myositis patients without anti-TIF1- γ or -HMGCR Abs than in general population. Further study is needed to clarify whether the higher risk of cancer is caused by cancer searching bias or there are other direct relations between cancer and myositis. doi:10.1016/j.jns.2017.08.765 738 WCN17-0730 SHIFT 1 - NEUROMUSCULAR DISORDERS Myositis and muscular inclusions in Nakajo-Nishimura syndrome T. Ayaki a , K. Murata b , N. Kanazawa c , A. Uruha d,e , I. Nishino d,e , K. Omura f , K. Sugie g , S. Kasagi h , M. Mori b , S. Ueno g , F. Furukawa c , H. Ito b , M. Urushitani i , R. Takahashi a . a Kyoto University, Department of Neurology, Kyoto, Japan; b Wakayama Medical University, Department of Neurology, Wakayama, Japan; c Wakayama Medical University, Department of Dermatology, Wakayama, Japan; d National Center of Neurology and Psychiatry NCNP, Department of Genome Medicine Development, Tokyo, Japan; e National Center of Neurology and Psychiatry NCNP, Department of Neuromuscular Research, Tokyo, Japan; f Kyoto University, Department of Rheumatology and Clinical Immunology, Kyoto, Japan; g Nara Medical University School of Medicine, Department of Neurology, Nara, Japan; h Kobe University Graduate School of Medicine, Department of Clinical Laboratory Center, Kobe, Japan; i Shiga University of Medical Science, Department of Neurology, Shiga, Japan Background: Nakajo-Nishimura syndrome (NNS) is an autosomal recessive disease caused by a homozygous mutation in the human proteasome subunit beta type 8 gene (PSMB8) that encodes the immunoproteasome subunit β5i. Clinical features of NNS include periodic fever, skin rash and joint deformity. Patients often develop progressive muscle weakness and atrophy. Immunosuppressive therapy is often administered but not effective enough to prevent the progression of the disease. Skin pathological feature is characterized with inflammatory change and accumulation of ubiquitinated proteins. Reported muscle changes include mild inflammatory change, rimmed vacuole and fibrosis change, but there are limited reports about cilinicopahological compar- ison of muscle pathology in genetically confirmed cases. Objective: Comparison of clinical features and muscle pathology in NNS patients. Patients and Methods/Material and Methods: We have examined clinical features and muscle pathology in 3 cases of NNS genetically diagnosed as having PSMB8 mutation. Results: All cases had episodes of typical periodic fever and skin rash. Later, they developed progressive muscle weakness and atrophy and Abstracts / Journal of the Neurological Sciences 381 (2017) 188–373 268