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Background As Japan's population continues to age, it is estimated that the number of people aged ≥75 years will exceed 20 million by 2025. Furthermore, over the past 10 years, we have not reduced the difference between life expectancy and healthy life expectancy. Therefore, the extension of healthy life expectancy and the development of a healthy society are the most urgent issues. In terms of medical care, the changing times have inevitably led to changes in disease structures and medical demands; therefore, the medical delivery system has had to be changed to meet these demands. As dementia rapidly increases, it is important to address "frailty," a condition in which people become more vulnerable to environmental factors as they age, and there is a need to provide services to older people, particularly the old-old, that emphasize quality of life in addition to medical care. To realize a super-aged society that will remain vigorous and vibrant for many years, we need to rethink the future of Japanese medicine and healthcare, and the state of society. Current situation and problems Disparity between healthy life expectancy and average life expectancy in the realization of a healthy society It is a challenge to build a society with a long and healthy life expectancy through comprehensive prevention and management of lifestyle-related diseases, as well as the elucidation of the factors that explain sex differences in healthy life expectancy, based on the recognition that lifestyle-related diseases in midlife are risk factors for frailty and dementia in old age. Challenges in medical care for building a super-aged and healthy society The challenges include promoting clinical guidelines suitable for older people, including lifestyle-related disease management, promoting comprehensive research on aging (basic research, clinical research and community collaboration research), and embodying a paradigm shift from "cure-seeking medical care" to "cure- and support-seeking medical care." Furthermore, the key to the future of integrated community care is the development of a comprehensive medical care system for older people in each region and the development of the next generation of medical personnel. Dissemination of frailty prevention measures in a super-aged society The concept of frailty encompasses the meaning of multifacetedness and reversibility; therefore, a comprehensive approach is required, including the renewal of conventional prevention activities in each region, such as the nutritional status of older people, physical activity including exercise, and various opportunities for social participation and participation conditions. Challenges of an unstable diet and undernutrition in older people According to the National Health and Nutrition Examination Survey of Japan, energy and protein intakes are low in Japanese people aged ≥75 years; particularly in people aged ≥80 years, low and insufficient intake of nutrients are prominent. Undernutrition in older people is increasing and is more pronounced in women. There are multiple factors behind this, including social factors, such as living alone, eating alone, poverty and other social factors, as well as problems with access to food security. Pharmacotherapy for older people: measures against polypharmacy In addition to the problems of adverse drug events, drug interactions, duplication of effects and the presence of drugs that "require particularly careful administration," it is also necessary to take measures against polypharmacy in older people, as well as medical economic issues, such as high drug costs and large amounts of remaining drugs. Barriers to this measure include multiple medical institution visits for each disease, lack of coordination between professions, and lack of understanding by patients and families. Role of local communities in a healthy society The decline in the working-age population is also a major challenge; however, we need to make a shift to use this declining birthrate and aging population as an opportunity rather than a crisis. As we look ahead to the coming of the 100-year age of life, we rethink the creation of a comprehensive society and community, and aim to create an age-free society where everyone can play an active role and live in peace, regardless of age. Contents of the proposal In this report, we have put together a vision for the future of an aging Japanese society from a broader perspective of how the environment and local communities should be, rather than simply from the perspective of individual health. We aim to convey this proposal to the Ministry of Health, Labor and Welfare, the Ministry of Education, Culture, Sports, Science and Technology, the Cabinet Office, and various professional organizations. The paradigm shift from "cure-seeking medical care" to "cure- and support-seeking medical care" should be promoted for the development of a healthy society While further promoting pre-emptive medical care in the medical care for older people, the development of multidisciplinary medical guidelines appropriate for older people should be promoted at the same time. In addition, we should promote basic aging research, clinical research (including the long-term care field) and transitional research that cover regional areas. Furthermore, while promoting the paradigm shift from "cure-seeking medical care" to "cure- and support-seeking medical care," the development of various comprehensive medical treatment systems for older people and the strengthening of integrated community care systems should be promoted. Development of the next generation of medical personnel to comprehensively deal with geriatric care, including training geriatric specialists, should be promoted As the number of older people with multimorbidities and frailty rapidly increases in the future, we should promote the development of the next generation of medical personnel who can comprehensively handle medical care for older people, including training leading geriatricians in cooperation with multiple professions in the integrated community care system to provide sufficient medical care. Countermeasures for frailty in older people should be promoted from medical and community planning perspectives To address frailty, which requires comprehensive evaluation and intervention, the three pillars of frailty prevention (nutrition, exercise and social participation) should be incorporated and addressed as part of community development within each municipality, taking into account local characteristics. In particular, it is necessary to revise the way of thinking about nutrition management in older people and the guidelines of the societies in the field. In addition, it is important to strengthen industry-academia-government-private partnerships in each region, taking into account not only medical issues, but also social factors, and encourage the development of momentum in the entire region regarding measures against undernutrition in older people. Polypharmacy measures should be promoted in pharmacotherapy for older people It is necessary to promote cooperation between physicians and pharmacists, establish other multiprofessional cooperation systems, and develop medical and long-term care insurance systems to support this. It is also essential to change the public's mindset, and awareness-raising activities at all levels are required, including the enhancement of educational materials for medical caregivers and the general public. In addition, the economic impact of healthcare using big data should be timely clarified. Innovation in medical and urban planning perspectives should be promoted In the future, it will be necessary to modify and update multidisciplinary approaches such as social participation (e.g. participation in a salon) with a view to innovation in both medical care and community development, especially on the idea of a symbiotic community. In addition, industry-academia-government-private partnership is necessary, including all aforementioned, such as places where people can play an active role in the rest of their lives (such as employment), promotion of human connections, promotion of technology to support older people and support for daily life. Geriatr Gerontol Int 2021; 21: 601-613.

Introduction Gestational intermittent hypoxia (IH), a hallmark of obstructive sleep apnea during gestation, alters respiratory neural control and diaphragm muscle contractile function in the offspring. The geniohyoid (GH) muscle is innervated by the respiratory-related hypoglossal nerve and plays a role in tongue traction and suckling, motor behaviors that then give way to chewing. Here, we aimed to investigate the effects of gestational exposure to IH on the muscle development and metabolism of GH and masseter muscles in male offspring rats. Materials and methods Pregnant Sprague-Dawley rats were exposed to IH (3-min periods of 4-21% O

Eosinophilic granulomatosis with polyangiitis (EGPA) is a rare condition of systemic vasculitis of small to medium-sized blood vessels. We herein report the case of a 75-year-old man who presented with hemiplegia on his right side due to cerebral infarction following myalgia and a high fever. He had no history of asthma or allergic rhinitis. He was diagnosed with EGPA based on the presence of eosinophilia, sinusitis suggested by magnetic resonance imaging, and muscle pathology. His hemiplegia improved rapidly after corticosteroid therapy. This case suggests that EGPA should be a differential diagnosis of cerebral infarction with myalgia and eosinophilia.

N-Benzyl-substituted phenethylamines (NBOMes) are psychoactive drugs, which induce various symptoms like serotonin syndrome, even at low doses. Recently, we reported the first lethal case of a designer drug, 2-(4-bromo-2, 5-dimethoxyphenyl)-NBOMe (25B-NBOMe) intoxication with severe rhabdomyolysis, evaluated by clinical, pathological, and toxicological analyses. We also confirmed that 25B-NBOMe can induce rhabdomyolysis using a zebrafish model. To further elucidate pathomechanism of NBOMes-induced rhabdomyolysis, we treated zebrafish with a similar designer drug, 2-(4-methyl-2, 5-dimethoxyphenyl)-NBOMe (25D-NBOMe). Zebrafish treated with a designer drug, 25D-NBOMe, were examined survival rate and were analyzed skeletal muscle degeneration by birefringence. They were also analyzed expression levels of 5-HT2A and 5-HT2C receptors and ryanodine receptor. The 25D-NBOMe-treated fish showed decreased survival rate and skeletal muscle degeneration detected by birefringence mimicking to those of 25B-NBOMe-treated fish. We revealed that 25D-NBOMe induced up-regulation of the expression of 5-HT2A and 5-HT2C receptors, and rhabdomyolysis was inhibited by the 5-HT2A receptor antagonist, aripiprazole and 5-HT2C receptor antagonist, SB242084. Moreover, ryanodine receptor expression was up-regulated in 25D-NBOMe-treated fish as compared to that of untreated fish, and the up-regulated expression of ryanodine receptor in 25D-NBOMe-treated fish was improved with co-treatment aripiprazole and SB242084. Our findings suggest that multiple 5-HT receptors have important roles in NBOMes-induced rhabdomyolysis together with other serotonin-related symptoms. Zebrafish is a highly useful model for therapeutic studies of rhabdomyolysis induced by psychoactive designer drugs.

Pathological diagnosis of dermal melanocytic tumors is often problematic owing to histological resemblance. Recently, cutaneous melanocytoma with CRTC1-TRIM11 (CMCT) was added to this category. However, only six cases have been reported so far. We herein present a case of a 77-year-old Japanese man with CMCT. The patient presented a nodule in the right thigh and underwent surgical resection. Histological examination indicated a well-demarcated 6 × 5 mm-sized tumor nodule in the dermis and subcutis. The tumor was amelanotic, consisting of uniform nests and fascicles of spindled, or epithelioid cells. The melanocytic nature was evident by immunohistochemistry. The CRTC1-TRIM11 fusion was detected by TRIM11 immunostaining, chromogenic in situ hybridization, and RT-PCR/direct sequencing. He has been free from the tumor for 1 year after additional resection. The main differential diagnosis of CMCT includes primary and metastatic dermal malignant melanomas (MM) and dermal/subcutaneous clear cell sarcoma (CCS). Additionally, histological overlap with paraganglioma-like dermal melanocytic tumor was considered. Although some investigators argue that CMCT is a variant of CCS, we think it should be separated from CCS, and subcutaneous/dermal CCS should be confined to tumors with EWSR1-ATF1/ CREB1 fusion. However, longer follow-up and more case studies are needed for revealing the true prognosis of CMCT.

The C-terminal Ig-domain of lamin A plays critical roles in cell function via interaction with proteins, DNA, and chromatin. Mutations in this domain are known to cause various diseases including Emery-Dreifuss muscular dystrophy (EDMD) and familial partial lipodystrophy (FPLD). Here we examined the biophysical and biochemical properties of mutant Ig-domains identified in patients with EDMD and FPLD. EDMD-related mutant Ig-domain showed decreased stability to heat and denaturant. This result was also confirmed by experiments using full-length mutant lamin A, although the decrease in melting temperature was much less than that of the mutant Ig-domain alone. The unstable EDMD Ig-domain disrupted the proper assembly of lamin A, resulting in abnormal paracrystal formation and decreased viscosity. In contrast, FPLD-related mutant Ig-domains were thermally stable, although they lost DNA binding function. Alanine substitution experiments revealed a functional domain of DNA binding in the Ig-domain. Thus, the overall biophysical property of Ig-domains is closely associated with clinical phenotype.

ObjectiveFacioscapulohumeral muscular dystrophy (FSHD) is a heterogenetic disorder predominantly characterized by progressive facial and scapular muscle weakness. Patients with FSHD either have a contraction of the D4Z4 repeat on chromosome 4q35 or mutations in D4Z4 chromatin modifiers SMCHD1 and DNMT3B, both causing D4Z4 chromatin relaxation and inappropriate expression of the D4Z4-encoded DUX4 gene in skeletal muscle. In this study, we tested the hypothesis whether LRIF1, a known SMCHD1 protein interactor, is a disease gene for idiopathic FSHD2.MethodsClinical examination of a patient with idiopathic FSHD2 was combined with pathologic muscle biopsy examination and with genetic, epigenetic, and molecular studies.ResultsA homozygous LRIF1 mutation was identified in a patient with a clinical phenotype consistent with FSHD. This mutation resulted in the absence of the long isoform of LRIF1 protein, D4Z4 chromatin relaxation, and DUX4 and DUX4 target gene expression in myonuclei, all molecular and epigenetic hallmarks of FSHD. In concordance, LRIF1 was shown to bind to the D4Z4 repeat, and knockdown of the LRIF1 long isoform in muscle cells results in DUX4 and DUX4 target gene expression.ConclusionLRIF1 is a bona fide disease gene for FSHD2. This study further reinforces the unifying genetic mechanism, which postulates that FSHD is caused by D4Z4 chromatin relaxation, resulting in inappropriate DUX4 expression in skeletal muscle.

Background Obtaining an adequate number of patients to conduct a natural history study for rare diseases such as Becker muscular dystrophy (BMD) is difficult. Objectives The present study used data from Remudy, a national registry for neuromuscular diseases in Japan, to conduct a phenotypic analysis of BMD. Methods We analyzed Remudy data of participants with dystrophinopathy. All participants who were aged 17 and older and were ambulant at age 13 were included in this study. Participants were divided into two groups: those with BMD who were ambulant at age 17, and those with intermediate muscular dystrophy (IMD) who lost ambulation by age 17. Frequent mutations were analyzed by age at ambulation, cardiopulmonary function, and genotype. For clinical comparisons, participants who were administered steroids were excluded. Results From July 2009 through September 2015, 192 participants had registered with Remudy. Mean participant age was 34.80±13.3 (range, 17-78) years, and 52.1% of participants were ambulant. Of the entire study population, 50.5% had cardiomyopathy and 35.9% had respiratory failure. Three participants required invasive ventilation and 30 required non-invasive ventilation. Nineteen of the 30 non-invasive ventilator users were part-time users. In total, 138 (71.9%) had BMD and 54 (28.1%) had IMD. The most frequent mutation was ex45_ex47del (36 participants). Among participants with frequent in-frame mutations, those with the ex45-49del mutation lost their ambulation earlier than those with the ex45_ex47del mutation. A total of 67 different exon deletions and duplications were identified in the study population. Conclusion We clarified the clinical phenotypes of Japanese patients with BMD/IMD using data from Remudy. Our results suggest that not only IMD but also BMD are associated with risk of respiratory dysfunction.

VCP mutations were first associated with inclusion body myopathy with Paget’s disease of bone and frontotemporal dementia (IBMPFD) but was later associated with amyotrophic lateral sclerosis and Charcot–Marie–Tooth disease. Now, a new name, “multisystem proteinopathy (MSP)”, is proposed for this condition. VCP encodes valosin-containing protein, which is involved in protein degradation in the ubiquitin proteasome system. We report here two MSP patients with two novel heterozygous missense variants in VCP: c.259G>T (p.Val87Phe) and c.376A>G (p.Ile126Val).

MDMB-CHMICA, a new synthetic cannabinoid (SC), has become prevalent since 2014 as an ingredient of recreational drugs. Reports on intoxication due to the drug have been increasing, which show diverse cardiovascular, psychiatric, and neuronal symptoms. Reports on sudden death and accidental death related to psychiatric disorders in MDMB-CHMICA intoxication have also increased, but the underlying mechanisms are largely unknown. As there has been no experimental study on the drug, we investigated the effects of peripheral injection of MDMB-CHMICA in conscious rats. MDMB-CHMICA induced rapid bradycardia and a slow pressor response. Cardiovascular responses to other SCs have been shown to be inhibited only by cannabinoid receptor-1 (CB1)-antagonists. However, the MDMB-CHMICA-induced bradycardia was inhibited not only by a CB1-antagonist, AM281, but also by a CB2-antagonist, AM630. Unlike other SCs, MDMB-CHMICA induced a gradual increase in mean blood pressure, which was marginally enhanced by the CB1- and CB2- antagonists. For the first time, we demonstrated that MDMB-CHMICA induces a thrashing hypermobile behavior in a CB1- and CB2-receptor-dependent manner, following catalepsy-like hypomobile behavior. This unexpected response to MDMB-CHMICA may help explain the mechanisms underlying the sudden deaths and accidents associated with its use.

Hepatocyte apoptosis has been implicated in the progression of nonalcoholic steatohepatitis. However, it is unclear whether the induction of tumor necrosis factor (TNF)-α-mediated hepatocyte apoptosis in the simple fatty liver triggers liver fibrosis. To address this question, high-fat diet-fed mice were repeatedly administered D-galactosamine, which increases the sensitivity of hepatocytes to TNF-α-mediated apoptosis. In mice treated with a high-fat diet plus D-galactosamine, hepatocyte apoptosis and liver fibrosis were induced, whereas both apoptosis and fibrosis were inhibited in these mice following gut sterilization with antimicrobials or knockout of TNF-α. Furthermore, liver fibrosis was diminished when hepatocyte apoptosis was inhibited by expressing a constitutively active inhibitor of nuclear factor κB kinase subunit β. Thus, hepatocyte apoptosis induced by intestinal dysbiosis or TNF-α up-regulation in the steatotic liver caused fibrosis. Organ fibrosis, including liver fibrosis, involves the interaction of cyclic adenosine monophosphate-response element-binding protein-binding protein (CBP) and β-catenin. Here, hepatocyte-specific CBP-knockout mice showed reduced liver fibrosis accompanied by hepatocyte apoptosis diminution; notably, liver fibrosis was also decreased in mice in which CBP was specifically knocked out in collagen-producing cells because the activation of these cells was now suppressed. Conclusion: TNF-α-mediated hepatocyte apoptosis induced fibrosis in the steatotic liver, and inhibition of CBP/β-catenin signaling attenuated the liver fibrosis due to the reduction of hepatocyte apoptosis and suppression of the activation of collagen-producing cells. Thus, targeting CBP/β-catenin may represent a new therapeutic strategy for treating fibrosis in nonalcoholic steatohepatitis. (Hepatology Communications 2018;2:407-420).

Summary: Myotonic dystrophy types 1 (DM1) and 2 (DM2) are dominantly inherited neuromuscular disorders caused by a toxic gain of function of expanded CUG and CCUG repeats, respectively. Although both disorders are clinically similar, congenital myotonic dystrophy (CDM), a severe DM form, is found only in DM1. CDM is also characterized by muscle fiber immaturity not observed in adult DM, suggesting specific pathological mechanisms. Here, we revealed upregulation of the interleukin-6 (IL-6) myokine signaling pathway in CDM muscles. We also found a correlation between muscle immaturity and not only IL-6 expression but also expanded CTG repeat length and CpG methylation status upstream of the repeats. Aberrant CpG methylation was associated with transcriptional dysregulation at the repeat locus, increasing the toxic RNA burden that upregulates IL-6. Because the IL-6 pathway is involved in myocyte maturation and muscle atrophy, our results indicate that enhanced RNA toxicity contributes to severe CDM phenotypes through aberrant IL-6 signaling. : Congenital myotonic dystrophy (CDM) manifests characteristic genetic (very large CTG repeat expansions), epigenetic (CpG hypermethylation upstream of the repeat), and phenotypic (muscle immaturity) features not seen in adult DM. Nakamori et al. find phenotype-genotype and epigenotype correlation in CDM muscle and reveal involvement of the IL-6 myokine signaling pathway in the disease process. Keywords: CTCF, ER stress, IL-6, muscular dystrophy, NF-κB, trinucleotide, cytokine, splicing

N-Benzyl-substituted 2C class phenethylamines (NBOMes) are psychoactive designer drugs, with strong hallucinogenic and stimulant effects, even at low doses. The designer drug, 2-(4-bromo-2, 5-dimethoxyphenyl)-N-(2-methoxybenzyl) ethanamine (25B-NBOMe) is considered to be one of the most potent agonists of the serotonin-2A (5-HT2A) receptor. Recently, we reported the first lethal case of 25B-NBOMe intoxication with severe rhabdomyolysis, concluded by clinical, pathological and toxicological analyses. There are currently no good animal models that closely recapitulate serotonin receptor-dependent rhabdomyolysis. In the present study, we created animal models of rhabdomyolysis using zebrafish larvae to study the pathomechanism of rhabdomyolysis, and demonstrated that 25B-NBOMe can simulate lethal rhabdomyolysis in this animal. Treatment of the larvae with 25B-NBOMe decreased their survival rate, locomotion, altered birefringence of the skeletal muscle and immunostainings for dystroglycan (a myoseptal protein) and myosin heavy chain (a myofibril protein), which were consistent with rhabdomyolysis. This 25B-NBOMe-induced rhabdomyolysis was inhibited by the 5-HT2A receptor antagonists ritanserin and aripirazole, but not by the 5-HT1A + 5-HT1B receptor antagonist propranolol and the 5-HT3 receptor antagonist granisetron, indicating 5-HT2A-dependent rhabdomyolysis. The 25B-NBOMe-treated zebrafish is, therefore, a highly useful model of rhabdomyolysis for studying the pathomechanism of rhabdomyolysis as well as for therapeutic drug screening.

Nemaline myopathy (NM) is a common form of congenital nondystrophic skeletal muscle disease characterized by muscular weakness of proximal dominance, hypotonia, and respiratory insufficiency but typically not cardiac dysfunction. Wide variation in severity has been reported. Intranuclear rod myopathy is a subtype of NM in which rod-like bodies are seen in the nucleus, and it often manifests as a severe phenotype. Although ten mutant genes are currently known to be associated with NM, only ACTA1 is associated with intranuclear rod myopathy. In addition, the genetic cause remains unclear in approximately 25%-30% of individuals with NM. We performed whole-exome sequencing on individuals with histologically confirmed but genetically unsolved NM. Our study included individuals with milder, later-onset NM and identified biallelic loss-of-function mutations in myopalladin (MYPN) in four families. Encoded MYPN is a sarcomeric protein exclusively localized in striated muscle in humans. Individuals with identified MYPN mutations in all four of these families have relatively mild, childhood- to adult-onset NM with slowly progressive muscle weakness. Walking difficulties were recognized around their forties. Decreased respiratory function, cardiac involvement, and intranuclear rods in biopsied muscle were observed in two individuals. MYPN was localized at the Z-line in control skeletal muscles but was absent from affected individuals. Homozygous knockin mice with a nonsense mutation in Mypn showed Z-streaming and nemaline-like bodies adjacent to a disorganized Z-line on electron microscopy, recapitulating the disease. Our results suggest that MYPN screening should be considered in individuals with mild NM, especially when cardiac problems or intranuclear rods are present.

Facioscapulohumeral muscular dystrophy (FSHD) is a heterogenetic disorder predominantly characterized by progressive facial and scapular muscle weakness. Patients with FSHD either have a contraction of the D4Z4 repeat on chromosome 4q35 or mutations in D4Z4 chromatin modifiers SMCHD1 and DNMT3B, both causing D4Z4 chromatin relaxation and inappropriate expression of the D4Z4-encodedClinical examination of a patient with idiopathic FSHD2 was combined with pathologic muscle biopsy examination and with genetic, epigenetic, and molecular studies.A homozygous

Mutations in dysferlin are responsible for a group of progressive, recessively inherited muscular dystrophies known as dysferlinopathies. Using recombinant proteins and affinity purification methods combined with liquid chromatography-tandem mass spectrometry (LC-MS/MS), we found that AMP-activated protein kinase (AMPK)γ1 was bound to a region of dysferlin located between the third and fourth C2 domains. Using ex vivo laser injury experiments, we demonstrated that the AMPK complex was vital for the sarcolemmal damage repair of skeletal muscle fibers. Injury-induced AMPK complex accumulation was dependent on the presence of Ca2+, and the rate of accumulation was regulated by dysferlin. Furthermore, it was found that the phosphorylation of AMPKα was essential for plasma membrane repair, and treatment with an AMPK activator rescued the membrane-repair impairment observed in immortalized human myotubes with reduced expression of dysferlin and dysferlin-null mouse fibers. Finally, it was determined that treatment with the AMPK activator metformin improved the muscle phenotype in zebrafish and mouse models of dysferlin deficiency. These findings indicate that the AMPK complex is essential for plasma membrane repair and is a potential therapeutic target for dysferlinopathy., Mutations in dysferlin are responsible for a group of progressive, recessively inherited muscular dystrophies known as dysferlinopathies. Using affinity purification methods combined with LC/MS/MS, Ono et al. found that AMPKγ1 was bound to dysferlin. The AMPK complex is essential for sarcolemmal repair and is a potential therapeutic target for dysferlinopathy.

Duchenne muscular dystrophy is a severe muscular disorder, often complicated with osteoporosis, and impaired renal function has recently been featured. We aimed to clarify the involvement of renal function in the pathogenesis of mineral and bone disorder in mdx mice, a murine model of the disease. We clearly revealed renal dysfunction in adult mdx mice, in which dehydration and hypercalcemia were contributed. We also examined the effects of dietary phosphorus (P) overload on phosphate metabolism. Serum phosphate and parathyroid hormone (PTH) levels were significantly increased in mdx mice by dietary P in a dose-dependent manner; however, bone alkaline phosphatase levels were significantly lower in mdx mice. Additionally, bone mineral density in mdx mice were even worsened by increased dietary P in a dose-dependent manner. These results suggested that the uncoupling of bone formation and resorption was enhanced by skeletal resistance to PTH due to renal failure in mdx mice.

Mutations in LMNA, encoding A-type lamins, lead to diverse disorders, collectively called "laminopathies," which affect the striated muscle, cardiac muscle, adipose tissue, skin, peripheral nerve, and premature aging. We describe a patient with limb-girdle muscular dystrophy type 1B (LGMD1B) carrying a heterozygous p.Arg377His mutation in LMNA, in whom skeletal muscle symptom onset was at the age of 65 years. Her weakness started at the erector spinae muscles, which showed marked pseudo-hypertrophy even at the age of 72 years. Her first episode of syncope was at 44 years; however, aberrant cardiac conduction was not revealed until 60 years. The p.Arg377His mutation has been previously reported in several familial LMNA-associated myopathies, most of which showed muscle weakness before the 6th decade. This is the first report of pseudo-hypertrophy of paravertebral muscles in LMNA-associated myopathies. The pseudo-hypertrophy of paravertebral muscles and the elderly-onset of muscle weakness make this case unique and reportable.

A middle-aged Japanese man presented with slowly progressive asymmetric weakness of legs and arm but had neither ptosis nor dysphagia. He had a family history of similar condition suggestive of autosomal dominant inheritance. A muscle biopsy showed mixture of neurogenic atrophy and myopathy with rimmed vacuoles. Furthermore we found intranuclear inclusions that had a fine structure mimicking that of inclusions reported in oculopharyngeal muscular dystrophy (OPMD). Immunohistochemical staining for polyadenylate-binding nuclear protein 1, which is identified within the nuclear inclusions of OPMD, demonstrated nuclear positivity in this case. However, OPMD was thought unlikely based on the clinical features and results of genetic analyses. Instead, a novel mutation in valosin-containing protein, c.376A>T (p.Ile126Phe), was revealed. A diagnosis of inclusion body myopathy associated with Paget disease of bone and frontotemporal dementia was made. This is the first report of polyadenylate-binding nuclear protein 1-positive nuclear inclusions in the muscle of this condition.

Danon disease, primary lysosome-associated membrane protein-2 (LAMP-2) deficiency, is characterized clinically by cardiomyopathy, myopathy and intellectual disability in boys. Because Danon disease is inherited in an X-linked dominant fashion, males are more severely affected than females, who usually have only cardiomyopathy without myopathy or intellectual disability; moreover, the onset of symptoms in females is usually in adulthood. We describe a girl with Danon disease who presented with hypertrophic cardiomyopathy and Wolff-Parkinson-White (WPW) syndrome at 12 years of age. Subsequently, she showed signs of mild learning disability and intellectual disability on psychological examinations. She had a de novo novel mutation in the LAMP-2 gene and harbored an identical c.749C > A (p.Ser250X) variant, resulting in a stop codon in exon 6. She showed decreased, but not completely absent LAMP-2 expression on immunohistochemical and Western blot analyses of a skeletal muscle biopsy specimen, which has been suggested to be caused by a 50% reduction in LAMP-2 expression (LAMP-2 haploinsufficiency) in female patients with Danon disease caused by a heterozygous null mutation. To our knowledge, our patient is one of the youngest female patients to have been given a diagnosis of Danon disease. In addition, this is the first documented case in a girl that was clearly associated with intellectual disability, which is very rare in females with Danon disease. Our findings suggest that studies of female patients with Danon disease can extend our understanding of the clinical features of this rare disease.

Limb-girdle muscular dystrophy type 2D (LGMD2D), an autosomal-recessive inherited LGMD, is caused by the mutations in SGCA. SGCA encodes alpha-sarcoglycan (SG) that forms a heterotetramer with other SGs in the sarcolemma, and comprises part of the dystrophin-glycoprotein complex. The frequency of LGMD2D is variable among different ethnic backgrounds, and so far only a few patients have been reported in Asia. We identified five patients with a novel homozygous mutation of c.101G>T (p.Arg34Leu) in SGCA from a big aboriginal family ethnically consisting of two tribes in Taiwan. Patient 3 is the maternal uncle of patients 1 and 2. All their parents, heterozygous for c.101G>T, denied consanguineous marriages although they were from the same tribe. The heterozygous parents of patients 4 and 5 were from two different tribes, originally residing in different geographic regions in Taiwan. Haplotype analysis showed that all five patients shared the same mutation-associated haplotype, indicating the probability of a founder effect and consanguinity. The results suggest that the carrier rate of c.101G>T in SGCA may be high in Taiwan, especially in the aboriginal population regardless of the tribes. It is important to investigate the prevalence of LGMD2D in Taiwan for early diagnosis and treatment.

Introduction We retrospectively reviewed respiratory and cardiac function in patients with dysferlinopathy, including 2 autopsy cases with respiratory dysfunction. Methods Subjects included 48 patients who underwent respiratory evaluation (n = 47), electrocardiography (n = 46), and echocardiography (n = 23). Results Of the 47 patients, 10 had reduced percent forced vital capacity (%FVC), and 4 required non-invasive positive pressure ventilation. %FVC was significantly correlated with disease duration, and mean %FVC was significantly lower in non-ambulatory patients, as well as in those aged ≥65 years with normal creatine kinase levels. On electrocardiography, QRS complex duration was prolonged in 19 patients, although no significant association with age, disease duration, or respiratory function was found. Echocardiography indicated no left ventricular dysfunction in any patient. Histopathology of autopsied cases revealed mild cardiomyopathy and moderate diaphragm involvement. Conclusion Patients with dysferlinopathy may develop severe respiratory failure and latent cardiac dysfunction. Both respiratory and cardiac function should be monitored diligently. Muscle Nerve 53: 394–401, 2016

Seiichiro Yokoyama1), Ayaka Koide2), Ichizo Nishino3), Yukiko Hayashi3, 4), Hirotaka Ohki1), Masaru Miura1), and Kazuhiko Shibuya1) 1) Department of Cardiology, Tokyo Metropolitan Children’s Medical Center, Tokyo, Japan 2) Department of Neurology, Tokyo Metropolitan Children’s Medical Center, Tokyo, Japan 3) Department of Neuromuscular Research, National Center of Neurology and Psychiatry, Tokyo, Japan 4) Department of Pathophysiology, Tokyo Medical University, Tokyo, Japan

Macrophages in liver tissue are widely defined as important inflammatory cells in chronic viral hepatitis due to their proinflammatory activity. We reported previously that interleukin-6 (IL-6) and tumor necrosis factor alpha (TNF-α) play significant roles in causing chronic hepatitis in hepatitis C virus (HCV) transgenic mice (S. Sekiguchi et al., PLoS One 7: e51656, 2012, http://dx.doi.org/10.1371/journal.pone.0051656 ). In addition, we showed that recombinant vaccinia viruses expressing an HCV nonstructural protein (rVV-N25) could protect against the progression of chronic hepatitis by suppression of macrophage activation. Here, we focus on the role of macrophages in liver disease progression in HCV transgenic mice and examine characteristic features of macrophages following rVV-N25 treatment. The number of CD11b + F4/80 + CD11c − CD206 + (M2) macrophages in the liver of HCV transgenic mice was notably increased compared to that of age-matched control mice. These M2 macrophages in the liver produced elevated levels of IL-6 and TNF-α. rVV-N25 infection suppressed the number and activation of M2 macrophages in liver tissue. These results suggested that inflammatory cytokines produced by M2-like macrophages contribute to the induction of chronic liver inflammation in HCV transgenic mice. Moreover, the therapeutic effect of rVV-N25 might be induced by the suppression of the number and activation of hepatic macrophages. IMPORTANCE HCV causes persistent infections that can lead to chronic liver diseases, liver fibrosis, and hepatocellular carcinoma; the search for an HCV curative is the focus of ongoing research. Recently, effective anti-HCV drugs have been developed; however, vaccine development still is required for the prevention and therapy of infection by this virus. We demonstrate here that M2 macrophages are important for the pathogenesis of HCV-caused liver diseases and additionally show that M2 macrophages contribute to the therapeutic mechanism observed following rVV-N25 treatment.

Caveolinopathies, caused by CAV3 mutations, can include several phenotypes such as rippling muscle disease, limb-girdle muscular dystrophy type 1C, distal myopathy, familial hypertrophic cardiomyopathy, and idiopathic hyperCKemia. Here we present characteristic skeletal muscle imaging findings in four patients with genetically defined childhood-onset RMD caused by CAV3 mutations and in one patient with congenital generalized lipodystrophy type 4 with muscular dystrophy due to polymerase I and transcript release factor (PTRF) mutations, which may have caused secondary deficiency of caveolin-3. Muscle MRI revealed that the rectus femoris and semitendinosus muscles were most commonly affected in the rippling muscle disease patients. Peripheral changes in the rectus femoris were specific and observed even in one of the younger patients in this study. Furthermore, muscle involvement extended to the semitendinosus muscles, biceps femoris, and gracilis with disease progression or increase in its severity. Similar patterns of involvement were observed on reviewing skeletal muscle images of various previously reported phenotypes of caveolinopathy; interestingly, patients with secondary deficiency of caveolin due to PTRF mutations revealed the same pattern. Thus, primary caveolinopathies and secondary deficiency of caveolin demonstrated specific findings on skeletal muscle imaging, regardless of the broad phenotypic spectrum of these two conditions.

Wnt/β-catenin is involved in every aspect of embryonic development and in the pathogenesis of many human diseases, and is also implicated in organ fibrosis. However, the role of β-catenin-mediated signaling on liver fibrosis remains unclear. To explore this issue, the effects of PRI-724, a selective inhibitor of the cAMP-response element-binding protein-binding protein (CBP)/β-catenin interaction, on liver fibrosis were examined using carbon tetrachloride (CCl4)- or bile duct ligation (BDL)-induced mouse liver fibrosis models. Following repetitive CCl4 administrations, the nuclear translocation of β-catenin was observed only in the non-parenchymal cells in the liver. PRI-724 treatment reduced the fibrosis induced by CCl4 or BDL. C-82, an active form of PRI-724, inhibited the activation of isolated primary mouse quiescent hepatic stellate cells (HSCs) and promoted cell death in culture-activated HSCs. During the fibrosis resolution period, an increase in F4/80+ CD11b+ and Ly6Clow CD11b+ macrophages was induced by CCl4 and was sustained for two weeks thereafter, even after having stopped CCl4 treatment. PRI-724 accelerated the resolution of CCl4-induced liver fibrosis, and this was accompanied by increased matrix metalloproteinase (MMP)-9, MMP-2, and MMP-8 expression in intrahepatic leukocytes. In conclusion, targeting the CBP/β-catenin interaction may become a new therapeutic strategy in treating liver fibrosis., Highlights • PRI-724, a selective inhibitor of CBP/β-catenin, suppresses liver fibrogenesis. • PRI-724 promotes fibrosis resolution in the liver. • PRI-724 decreases collagen production from myofibroblasts. • PRI-724 increases the production of MMPs from macrophages. Although liver fibrosis is becoming increasingly recognized as a major cause of morbidity and mortality in most chronic liver diseases, there are few—if any—treatment strategies available that specifically target the pathogenesis of fibrosis. In this study, we examined whether PRI-724, a selective inhibitor of the cAMP-response element-binding protein-binding protein (CBP)/β-catenin interaction, has therapeutic potential for liver fibrosis using mouse models. The results suggest a possibility that PRI-724 can be a candidate for new anti-fibrotic drugs for liver cirrhosis.

Context There is no current standard among myopathologists for reporting muscle biopsy findings. The National Institute of Neurological Disorders and Stroke has recently launched a common data element (CDE) project to standardize neuromuscular data collected in clinical reports and to facilitate their use in research. Objective To develop a more-uniform, prospective reporting tool for muscle biopsies, incorporating the elements identified by the CDE project, in an effort to improve reporting and educational resources. Design The variation in current biopsy reporting practice was evaluated through a study of 51 muscle biopsy reports from self-reported diagnoses of genetically confirmed or undiagnosed muscle disease from the Congenital Muscle Disease International Registry. Two reviewers independently extracted data from deidentified reports and entered them into the revised CDE format to identify what was missing and whether or not information provided on the revised CDE report (complete/incomplete) could be successfully interpreted by a neuropathologist. Results Analysis of the data highlighted showed (1) inconsistent reporting of key clinical features from referring physicians, and (2) considerable variability in the reporting of pertinent positive and negative histologic findings by pathologists. Conclusions We propose a format for muscle-biopsy reporting that includes the elements in the CDE checklist and a brief narrative comment that interprets the data in support of a final interpretation. Such a format standardizes cataloging of pathologic findings across the spectrum of muscle diseases and serves emerging clinical care and research needs with the expansion of genetic-testing therapeutic trials.

Hepatitis C virus (HCV) is a leading cause of chronic liver disease, cirrhosis, and hepatocellular carcinoma. To address the molecular basis of HCV pathogenesis using tupaias (Tupaia belangeri), we characterized host responses upon HCV infection. Adult tupaias were infected with HCV genotypes 1a, 1b, 2a, or 4a. Viral RNA, alanine aminotransferase, anti-HCV core and anti-nonstructural protein NS3 antibody titres, reactive oxygen species (ROS), and anti-3β-hydroxysterol-Δ24reductase (DHCR24) antibody levels were measured at 2-week intervals from 0 to 41 weeks postinfection. All HCV genotypes established infections and showed intermittent HCV propagation. Moreover, all tupaias produced anti-core and anti-NS3 antibodies. ROS levels in sera and livers were significantly increased, resulting in induction of DHCR24 antibody production. Similarly, lymphocytic infiltration, disturbance of hepatic cords, and initiation of fibrosis were observed in livers from HCV-infected tupaias. Intrahepatic levels of Toll-like receptors 3, 7, and 8 were significantly increased in all HCV-infected tupaias. However, interferon-β was only significantly upregulated in HCV1a- and HCV2a-infected tupaias, accompanied by downregulation of sodium taurocholate cotransporting polypeptide. Thus, our findings showed that humoral and innate immune responses to HCV infection, ROS induction, and subsequent increases in DHCR24 auto-antibody production occurred in our tupaia model, providing novel insights into understanding HCV pathogenesis.

Background Chronic increases in the levels of the inflammatory cytokine interleukin-6 (IL-6) in serum and skeletal muscle are thought to contribute to the progression of muscular dystrophy. Dystrophin/utrophin double-knockout (dKO) mice develop a more severe and progressive muscular dystrophy than the mdx mice, the most common murine model of Duchenne muscular dystrophy (DMD). In particular, dKO mice have smaller body sizes and muscle diameters, and develop progressive kyphosis and fibrosis in skeletal and cardiac muscles. As mdx mice and DMD patients, we found that IL-6 levels in the skeletal muscle were significantly increased in dKO mice. Thus, in this study, we aimed to analyze the effects of IL-6 receptor (IL-6R) blockade on the muscle pathology of dKO mice. Methods Male dKO mice were administered an initial injection (200 mg/kg intraperitoneally (i.p.)) of either the anti-IL-6R antibody MR16-1 or an isotype-matched control rat IgG at the age of 14 days, and were then given weekly injections (25 mg/kg i.p.) until 90 days of age. Results Treatment of dKO mice with the MR16-1 antibody successfully inhibited the IL-6 pathway in the skeletal muscle and resulted in a significant reduction in the expression levels of phosphorylated signal transducer and activator of transcription 3 in the skeletal muscle. Pathologically, a significant increase in the area of embryonic myosin heavy chain-positive myofibers and muscle diameter, and reduced fibrosis in the quadriceps muscle were observed. These results demonstrated the therapeutic effects of IL-6R blockade on promoting muscle regeneration. Consistently, serum creatine kinase levels were decreased. Despite these improvements observed in the limb muscles, degeneration of the diaphragm and cardiac muscles was not ameliorated by the treatment of mice with the MR16-1 antibody. Conclusion As no adverse effects of treatment with the MR16-1 antibody were observed, our results indicate that the anti-IL-6R antibody is a potential therapy for muscular dystrophy particularly for promoting skeletal muscle regeneration. Electronic supplementary material The online version of this article (10.1186/s13395-017-0140-z) contains supplementary material, which is available to authorized users.

Introduction Mutations in the small heat shock protein 22 gene (HSPB8) have been associated with Charcot-Marie-Tooth type 2L, distal hereditary motor neuropathy (dHMN) type IIa and, more recently, distal myopathy/myofibrillar myopathy (MFM) with protein aggregates and TDP-43 inclusions. Objective To report a novel family with HSPB8 K141E-related dHMN/MFM and to investigate, in a patient muscle biopsy, whether the presence of protein aggregates was paralleled by altered TDP-43 function. Methods We reviewed clinical and genetic data. We assessed TDP-43 expression by qPCR and alternative splicing of four previously validated direct TDP-43 target exons in four genes by RT-PCR. Results The triplets and their mother presented in the II-III decade of life with progressive weakness affecting distal and proximal lower limb and truncal muscles. Nerve conduction study showed a motor axonal neuropathy. The clinical features, the moderately raised CK levels, the selective pattern of muscle involvement at MRI and the pathological changes on muscle biopsy, including the presence of protein aggregates, supported the diagnosis of a contemporary primary muscle involvement. In affected muscle tissue we observed a consistent alteration of TDP-43-dependent splicing in 3 out of 4 TDP-43-target transcripts (POLDIP3, FNIP1 and BRD8), as well as a significant decrease of TDP-43 mRNA levels. Discussion Our study confirms the role of mutated HSPB8 as a cause of a combined neuromuscular disorder encompassing dHMN and MFM with protein aggregates. We identified impaired RNA metabolism, secondary to TDP-43 loss of function, as a possible pathologic mechanism of HSPB8 K141E toxicity, leading to muscle and nerve degeneration. This article is protected by copyright. All rights reserved.

Background and objective Marinesco-Sjogren syndrome (MSS) is an autosomal recessive infantile-onset disorder characterized by cataracts, cerebellar ataxia, and progressive myopathy caused by mutation of SIL1. In mice, a defect in SIL1 causes endoplasmic reticulum (ER) chaperone dysfunction, leading to unfolded protein accumulation and increased ER stress. However, ER stress and the unfolded protein response (UPR) have not been investigated in MSS patient-derived cells. Methods Lymphoblastoid cell lines (LCLs) were established from four MSS patients. Spontaneous and tunicamycin-induced ER stress and the UPR were investigated in MSS-LCLs. Expression of UPR markers was analyzed by western blotting. ER stress-induced apoptosis was analyzed by flow cytometry. The cytoprotective effects of ER stress modulators were also examined. Results MSS-LCLs exhibited increased spontaneous ER stress and were highly susceptible to ER stress-induced apoptosis. The inositol-requiring protein 1α (IRE1α)-X-box-binding protein 1 (XBP1) pathway was mainly upregulated in MSS-LCLs. Tauroursodeoxycholic acid (TUDCA) attenuated ER stress-induced apoptosis. Conclusion MSS patient-derived cells exhibit increased ER stress, an activated UPR, and susceptibility to ER stress-induced death. TUDCA reduces ER stress-induced death of MSS patient-derived cells. The potential of TUDCA as a therapeutic agent for MSS could be explored further in preclinical studies.

Background In hereditary myopathy with early respiratory failure (HMERF), cytoplasmic bodies (CBs) are often localised in subsarcolemmal regions, with necklace-like alignment (necklace CBs), in muscle fibres although their sensitivity and specificity are unknown. Objective To elucidate the diagnostic value of the necklace CBs in the pathological diagnosis of HMERF among myofibrillar myopathies (MFMs). Methods We sequenced the exon 343 of TTN gene (based on ENST00000589042), which encodes the fibronectin-3 (FN3) 119 domain of the A-band and is a mutational hot spot for HMERF, in genomic DNA from 187 patients from 175 unrelated families who were pathologically diagnosed as MFM. We assessed the sensitivity and specificity of the necklace CBs for HMERF by re-evaluating the muscle pathology of our patients with MFM. Results TTN mutations were identified in 17 patients from 14 families, whose phenotypes were consistent with HMERF. Among them, 14 patients had necklace CBs. In contrast, none of other patients with MFM had necklace CBs except for one patient with reducing body myopathy. The sensitivity and specificity were 82% and 99%, respectively. Positive predictive value was 93% in the MFM cohort. Conclusions The necklace CB is a useful diagnostic marker for HMERF. When muscle pathology shows necklace CBs, sequencing the FN3 119 domain of A-band in TTN should be considered.

The store-operated Ca(2+) release-activated Ca(2+) (CRAC) channel is activated by diminished luminal Ca(2+) levels in the endoplasmic reticulum and sarcoplasmic reticulum (SR), and constitutes one of the major Ca(2+) entry pathways in various tissues. Tubular aggregates (TAs) are abnormal structures in the skeletal muscle, and although their mechanism of formation has not been clarified, altered Ca(2+) homeostasis related to a disordered SR is suggested to be one of the main contributing factors. TA myopathy is a hereditary muscle disorder that is pathologically characterized by the presence of TAs. Recently, dominant mutations in the STIM1 gene, encoding a Ca(2+) sensor that controls CRAC channels, have been identified to cause tubular aggregate myopathy (TAM). Here, we identified heterozygous missense mutations in the ORAI1 gene, encoding the CRAC channel itself, in three families affected by dominantly inherited TAM with hypocalcemia. Skeletal myotubes from an affected individual and HEK293 cells expressing mutated ORAI1 proteins displayed spontaneous extracellular Ca(2+) entry into cells without diminishment of luminal Ca(2+) or the association with STIM1. Our results indicate that STIM1-independent activation of CRAC channels induced by dominant mutations in ORAI1 cause altered Ca(2+) homeostasis, resulting in TAM with hypocalcemia.

Of 207 adult patients with idiopathic inflammatory myopathies, detection of autoantibodies by RNA immunoprecipitation showed that 99 patients (48%) were antibody-positive. We divided these 99 into five subgroups: anti-signal recognition particle (SRP), anti-aminoacyl transfer RNA synthetase, anti-Ku, anti-U1RNP, and anti-SSA/B. Younger age at onset, severe weakness, muscle atrophy, elevated creatine kinase, and necrosis in muscle fibers without inflammatory cell infiltration were found significantly more frequently among the patients with anti-SRP antibodies (n=41) compared to the antibody-negative patients (n=108). Autoantibody detection by RNA immunoprecipitation can provide useful information associated with clinical and histological findings.

We herein report a 32-year-old woman with adult-onset reducing body myopathy (RBM) who had a mutation in the four-and-a-half LIM domain 1 gene (FHL1) and showed a marked asymmetrical involvement of sternocleidomastoid and trapezius muscles. At 30 years of age she noticed bilateral foot drop, and over the next two years developed difficulty raising her right arm. At 32 years of age she was admitted to our hospital for a diagnostic evaluation. Neurological examination showed moderate weakness and atrophy of her right sternocleidomastoid muscle, right trapezius muscle, and bilateral upper proximal muscles. There were severe weakness and atrophy of her bilateral tibialis anterior muscles. Her deep tendon reflexes were hypoactive in her upper extremities. Her serum creatine kinase level was mildly increased. Muscle biopsy specimens from the left tibialis anterior muscle revealed marked variation in fiber size, some necrotic or regenerating fibers, and reducing bodies. Gene analysis of FHL1 demonstrated a mutation: a heterozygous missense mutation of c.377G>A (p. C126T) in FHL1. Compared with previous adult-onset RBM cases harboring mutations in FHL1, our case was characterized by asymmetrical atrophy of the sternocleidomastoid and trapezius muscles.

Patients with GNE myopathy, a progressive and debilitating disease caused by a genetic defect in sialic acid biosynthesis, rely on supportive care and eventually become wheelchair-bound. To elucidate whether GNE myopathy is treatable at a progressive stage of the disease, we examined the efficacy of sialic acid supplementation on symptomatic old GNE myopathy mice that have ongoing, active muscle degeneration. We examined the therapeutic effect of a less metabolized sialic acid compound (6'-sialyllactose) or free sialic acid (N-acetylneuraminic acid) by oral, continuous administration to 50-week-old GNE myopathy mice for 30 weeks. To evaluate effects on their motor performance in living mice, spontaneous locomotion activity on a running wheel was measured chronologically at 50, 65, 72 and 80 weeks of age. The size, force production, and pathology of isolated gastrocnemius muscle were analysed at the end point. Sialic acid level in skeletal muscle was also measured. Spontaneous locomotion activity was recovered in 6'-sialyllactose-treated mice, while NeuAc-treated mice slowed the disease progression. Treatment with 6'-sialyllactose led to marked restoration of hyposialylation in muscle and consequently to robust improvement in the muscle size, contractile parameters, and pathology as compared to NeuAc. This is due to the fact that 6'-sialyllactose is longer working as it is further metabolized to free sialic acid after initial absorption. 6'-sialyllactose ameliorated muscle atrophy and degeneration in symptomatic GNE myopathy mice. Our results provide evidence that GNE myopathy can be treated even at a progressive stage and 6'-sialyllactose has more remarkable advantage than free sialic acid, providing a conceptual proof for clinical use in patients.

Mutations in the glucosamine (UDP-N-acetyl)-2-epimerase/N-acetylmannosamine kinase gene cause GNE myopathy, a mildly progressive autosomal recessive myopathy. We performed a prospective natural history study in 24 patients with GNE myopathy to select evaluation tools for use in upcoming clinical trials. Patient clinical conditions were evaluated at study entry and one-year follow-up. Of the 24 patients, eight (33.3%) completed a standard 6-min walk test without assistance. No cardiac events were observed. Summed manual muscle testing of 17 muscles, grip power, and percent force vital capacity (%FVC) were significantly reduced (p0.05), and scores for 6-min walk test and gross motor function measure were decreased (p0.1) after one year. The decrement in %FVC was significant among non-ambulant patients, whereas the decrement in grip power tended to be greater among ambulant patients. The 6-min walk test, gross motor function measure, manual muscle testing, grip power, and %FVC reflect annual changes and are thus considered good evaluation tools for clinical trials.

A boy, who had shown muscle weakness and hypotonia from early childhood and fiber type disproportion (FTD) with no dystrophic changes on muscle biopsy, was initially diagnosed as having congenital fiber type disproportion (CFTD). Subsequently, he developed cardiac conduction blocks. We reconsidered the diagnosis as possible LMNA-myopathy and found a heterozygous mutation in the LMNA gene. This encouraged us to search for LMNA mutations on 80 patients who met the diagnostic criteria of CFTD with unknown cause. Two patients including the above index case had heterozygous in-frame deletion mutations of c.367_369delAAG and c.99_101delGGA in LMNA, respectively. Four of 23 muscular dystrophy patients with LMNA mutation also showed fiber type disproportion (FTD). Importantly, all FTD associated with LMNA-myopathy were caused by hypertrophy of type 2 fibers as compared with age-matched controls, whereas CFTD with mutations in ACTA1 or TPM3 showed selective type 1 fiber atrophy but no type 2 fiber hypertrophy. Although FTD is not a constant pathological feature of LMNA-myopathy, we should consider the possibility of LMNA-myopathy whenever a diagnosis of CFTD is made and take steps to prevent cardiac insufficiency.

The patient was a 53-year-old male. He showed steppage gait at the age of 11 and equinus foot at 13. He walked unaided with shoe-insoles to support his heels. Atrial fibrillation and cardiac hypertrophy were found in his 30s, and ventricular tachycardia (VT) was observed at the age of 48. Electrophysiological studies were performed, but VT was not sustained, symptomatic, or showed signs of infra-Hisian block, and a pacemaker was not indicated. At 53, he was introduced to a neurologist because of tetraplegia after the first episode of syncope. A spinal MR showed ossification of posterior longitudinal ligament (OPLL) and central cervical cord injury. Furthermore, he presented not only contracture in his shoulder, elbow, and ankles but also atrophy in his scapulohumeral and gastrocnemius muscles. In accordance with a diagnosis of Emery-Dreifuss muscular dystrophy (EDMD), provocative testing of VT was carried out, and a cardiac resynchronization therapy defibrillator (CRT-D) was implanted. Later, a mutation analysis of the LMNA gene disclosed a known missense mutation of p.Arg377His, and we diagnosed him as EDMD2 (laminopathy). Contractures could be the clue to diagnose EDMD and indicate the need for pacemakers and defibrillators in patients with cardiac conduction disorders.

International audience; Laminopathies are tissue-selective diseases that affect differently in organ systems. Mutations in nuclear envelopes, emerin (Emd) and lamin A/C (Lmna) genes, cause clinically indistinguishable myopathy called Emery-Dreifuss muscular dystrophy (EDMD) and limb-girdle muscular dystrophy. Several murine models for EDMD have been generated; however, emerin-null (Emd) mice do not show obvious skeletal and cardiac muscle phenotypes, and Lmna H222P/H222P mutant (H222P) mice show only a mild phenotype in skeletal muscle when they already have severe cardiomyopathy. Thus, the underlying molecular mechanism of muscle involvement due to nuclear abnormalities is still unclarified. We generated double mutant (Emd-/-/LmnaH222P/H222P; EH) mice to characterize dystrophic changes and to elucidate interactions between emerin and lamin A/C in skeletal and cardiac muscles. As H222P mice, EH mice grow normally and have breeding productivity. EH mice showed severer muscle involvement compared with that of H222P mice which was an independent of cardiac abnormality at 12 weeks of age. Nuclear abnormalities, reduced muscle fiber size and increased fibrosis were prominent in EH mice. Roles of emerin and lamin A/C in satellite cells function and regeneration of muscle fiber were also evaluated by cardiotoxin-induced muscle injury. Delayed increases in myog and myh3 expression were seen in both H222P and EH mice; however, the expression levels of those genes were similar with control and regenerated muscle fiber size was not different at day 7 after injury. These results indicate that EH mouse is a suitable model for studying skeletal muscle involvement, independent of cardiac function, in laminopathies and an interaction between emerin and lamin A/C in different tissues.