Linking LRP12 CGG repeat expansion to inherited peripheral neuropathy.

BACKGROUND: The causative genes for over 60% of inherited peripheral neuropathy (IPN) remain unidentified. This study endeavours to enhance the genetic diagnostic rate in IPN cases by conducting screenings focused on non-coding repeat expansions. METHODS: We gathered data from 2424 unrelated Japanese patients diagnosed with IPN, among whom 1555 cases with unidentified genetic causes, as determined through comprehensive prescreening analyses, were selected for the study. Screening for CGG non-coding repeat expansions in LRP12, GIPC1 and RILPL1 genes was conducted using PCR and long-read sequencing technologies. RESULTS: We identified CGG repeat expansions in LRP12 from 44 cases, establishing it as the fourth most common aetiology in Japanese IPN. Most cases (29/37) exhibited distal limb weakness, without ptosis, ophthalmoplegia, facial muscle weakness or bulbar palsy. Neurogenic changes were frequently observed in both needle electromyography (97%) and skeletal muscle tissue (100%). In nerve conduction studies, 28 cases primarily showed impairment in motor nerves without concurrent involvement of sensory nerves, consistent with the phenotype of hereditary motor neuropathy. In seven cases, both motor and sensory nerves were affected, resembling the Charcot-Marie-Tooth (CMT) phenotype. Importantly, the mean CGG repeat number detected in the present patients was significantly shorter than that of patients with LRP12-oculopharyngodistal myopathy (p<0.0001). Additionally, GIPC1 and RILPL1 repeat expansions were absent in our IPN cases. CONCLUSION: We initially elucidate LRP12 repeat expansions as a prevalent cause of CMT, highlighting the necessity for an adapted screening strategy in clinical practice, particularly when addressing patients with IPN.

Hematopoietic Prostaglandin D Synthase Is Increased in Mast Cells and Pericytes in Autopsy Myocardial Specimens from Patients with Duchenne Muscular Dystrophy.

The leading cause of death for patients with Duchenne muscular dystrophy (DMD), a progressive muscle disease, is heart failure. Prostaglandin (PG) D2, a physiologically active fatty acid, is synthesized from the precursor PGH2 by hematopoietic prostaglandin D synthase (HPGDS). Using a DMD animal model (mdx mice), we previously found that HPGDS expression is increased not only in injured muscle but also in the heart. Moreover, HPGDS inhibitors can slow the progression of muscle injury and cardiomyopathy. However, the location of HPGDS in the heart is still unknown. Thus, this study investigated HPGDS expression in autopsy myocardial samples from DMD patients. We confirmed the presence of fibrosis, a characteristic phenotype of DMD, in the autopsy myocardial sections. Additionally, HPGDS was expressed in mast cells, pericytes, and myeloid cells of the myocardial specimens but not in the myocardium. Compared with the non-DMD group, the DMD group showed increased HPGDS expression in mast cells and pericytes. Our findings confirm the possibility of using HPGDS inhibitor therapy to suppress PGD2 production to treat skeletal muscle disorders and cardiomyopathy. It thus provides significant insights for developing therapeutic drugs for DMD.

Clinical trajectory of a patient with filaminopathy who developed arrhythmogenic cardiomyopathy, myofibrillar myopathy, and multiorgan tumors.

We report a case of a patient presenting with arrhythmogenic cardiomyopathy, myofibrillar myopathy, and multiorgan tumors. A 41-year-old woman with a history of hypertrophic cardiomyopathy, diagnosed at 6 years of age, developed scoliosis after puberty. Following spinal surgery to address the scoliosis, she developed recurrent severe arrhythmia and heart failure. She developed hypoventilation at age 29 years. Proximal dominant weakness and mild elevation of serum creatine kinase indicated possible myopathy. Myofibrillar myopathy was diagnosed by muscle biopsy at age 30 year. Acute abdomen was repeatedly reported from age 33 years, eventually leading to a diagnosis of gastric polyp and erosive ulcer. A urinary bladder tumor was found at age 35 years, and breast cancer was diagnosed at age 40 years. Whole exome sequencing detected a heterozygous missense mutation in Filamin C. Recent evidences suggest that filamins are associated with tumors, and this case further highlights the clinical spectrum of filaminopathy.

[A case study of a patient with myotonic dystrophy type 1 whose gait disturbance was improved by gait training with hybrid assistive limbs].

A Japanese woman first noticed dysarthria at the age of 23. She visited a hospital at the age of 32 and was diagnosed as having myotonic dystrophy clinically. She was diagnosed genetically as having myotonic dystrophy type 1 at 47 years old with 160-270 CTG repeats on the DMPK gene. At the age of 48, she needed non-invasive positive pressure ventilation because of hypoxia at night. Her gait function also deteriorated. She could not stand up from the supine position by herself. However, when she stood, she could walk without a cane for a short distance. She was admitted to our hospital to receive rehabilitation against progressive gait disturbance at the age of 53. She received gait training with hybrid assistive limb® (HAL®). We evaluated some parameters such as walking distance of 2-minute walk test (2MWT), gait speed /cadence/stride length of 10-meter walk test (10MWT), before and just after the course. The first course was performed in September 2017 and the second was done in May 2018 so the interval was about six months. After two courses of HAL® gait training, the distance on the 2-minute walk test increased from 111 m to 154 m, the average speed and the cadence of 10MWT improved from 2.01 m/s to 2.78 m/s and from 2.21 steps/s to 3.05 steps/s respectively. The score of the muscular disability quality of life (QOL) rating scale was also improved. The factors including "defecation," "breathing," and "ADL" suggest that the patient's physical abilities improved and she could move easily. Other factors such as "hope", "activity" and "human relationship" suggest that patient's mood improved after the HAL® training.It was suggested that HAL® gait training could improve QOL as well as gait function in patients with progressive neuromuscular disorder.

Clinicopathologic Features of Oculopharyngodistal Myopathy With LRP12 CGG Repeat Expansions Compared With Other Oculopharyngodistal Myopathy Subtypes.

Importance: Repeat expansion of CGG in LRP12 has been identified as the causative variation of oculopharyngodistal myopathy (OPDM). However, to our knowledge, the clinicopathologic features of OPDM with CGG repeat expansion in LRP12 (hereafter referred to as OPDM_LRP12) remain unknown. Objective: To identify and characterize the clinicopathologic features of patients with OPDM_LRP12. Design, Setting, and Participants: This case series included 208 patients with a clinical or clinicopathologic diagnosis of oculopharyngeal muscular dystrophy (OPDM) from January 1, 1978, to December 31, 2020. Patients with GCN repeat expansions in PABPN1 were excluded from the study. Repeat expansions of CGG in LRP12 were screened by repeat primed polymerase chain reaction and/or Southern blot. Main Outcomes and Measures: Clinical information, muscle imaging data obtained by either computed tomography or magnetic resonance imaging, and muscle pathologic characteristics. Results: Sixty-five Japanese patients with OPDM (40 men [62%]; mean [SD] age at onset, 41.0 [10.1] years) from 59 families with CGG repeat expansions in LRP12 were identified. This represents the most common OPDM subtype among all patients in Japan with genetically diagnosed OPDM. The expansions ranged from 85 to 289 repeats. A negative correlation was observed between the repeat size and the age at onset (r2 = 0.188, P = .001). The most common initial symptoms were ptosis and muscle weakness, present in 24 patients (37%). Limb muscle weakness was predominantly distal in 53 of 64 patients (83%), but 2 of 64 patients (3%) had predominantly proximal muscle weakness. Ptosis was observed in 62 of 64 patients (97%), and dysphagia or dysarthria was observed in 63 of 64 patients (98%). A total of 21 of 64 patients (33%) had asymmetric muscle weakness. Aspiration pneumonia was seen in 11 of 64 patients (17%), and 5 of 64 patients (8%) required mechanical ventilation. Seven of 64 patients (11%) developed cardiac abnormalities, and 5 of 64 patients (8%) developed neurologic abnormalities. Asymmetric muscle involvement was detected on computed tomography scans in 6 of 27 patients (22%) and on magnetic resonance imaging scans in 4 of 15 patients (27%), with the soleus and the medial head of the gastrocnemius being the worst affected. All 42 muscle biopsy samples showed rimmed vacuoles. Intranuclear tubulofilamentous inclusions were observed in only 1 of 5 patients. Conclusions and Relevance: This study suggests that OPDM_LRP12 is the most frequent OPDM subtype in Japan and is characterized by oculopharyngeal weakness, distal myopathy that especially affects the soleus and gastrocnemius muscles, and rimmed vacuoles in muscle biopsy.

[A case of systemic AL amyloidosis diagnosed on muscle biopsy].

A 69-year-old man was admitted to our hospital with a 1-year history of progressive easy fatigability while walking. He presented with proximal muscle weakness dominant in the lower extremities, hoarseness, and mild dysphagia. Muscle pseudo-hypertrophy was observed in the gastrocnemius. A biopsy specimen from the left deltoid muscle revealed amyloid deposition in the blood vessels and ring-like fibers. These findings suggested amyloid myopathy. The serum and urine immunofixation electrophoresis detected κ type Bence-Jones proteins, and bone marrow examination showed an increase in atypical plasma cells; thus, we established a diagnosis of multiple myeloma. Thereafter, he experienced frequent diarrhea, and the gastrointestinal endoscopy revealed extensive amyloid deposition in the upper and lower digestive tract. We started treatment with lenalidomide and dexamethasone; however, his condition worsened, and he died of aspiration pneumonia. Amyloid myopathy indicated systemic AL amyloidosis; therefore, muscle biopsy was necessary in this case.

[A case of meningoencephalitis associated with pembrolizumab treated for squamous cell lung cancer].

A 61-year-old man with squamous cell lung cancer was admitted to our hospital because of consciousness disturbance after treated with pembrolizumab. Cerebrospinal fluid examination revealed increased protein level (209.2 mg/dl) and lymphocytic pleocytosis(79/µl). He was diagnosed as a meningoencephalitis probably caused by an immune-related adverse event (irAE) of immune checkpoint inhibitors (ICIs), and was successfully treated with 1,000 mg methylprednisolone intravenously for 3 days twice and the consequent oral 1 mg/kg prednisolone. As ICIs, which activate the immune systems, are becoming important choices of the treatments against malignancies, we should keep the possibility of irAE in mind and, when needed, start the treatment as soon as possible.

Microvascular disturbance with decreased pericyte coverage is prominent in the ventral horn of patients with amyotrophic lateral sclerosis.

In amyotrophic lateral sclerosis (ALS) there is emerging evidence for vasculature disturbance. The aim of this study was to investigate the area of predominant vasculature disturbance in ALS. We used immunohistochemistry to quantitatively evaluate the microvascular density (MVD) and pericyte coverage (PC) in the lumbar spinal cord of 25 ALS patients and six controls. In controls, MVD was almost equal in the ventral horn (VH) and dorsal horn (DH). In the VH of ALS, MVD was significantly increased, and PC was significantly decreased compared with the DH in ALS and the VH in controls (p < 0.001), possibly reflecting that PC is an essential requirement for the vasculature in the VH. We then found a significant relationship between the severity of aberrant angiogenesis and the use of artificial respiratory support (ARS). In conclusion, vasculature disturbance is observed in all ALS patients including patients with ARS. Therefore, breakdown of the blood-spinal cord barrier due to aberrant angiogenesis with decreased PC may be responsible for the predominant neuronal death in the VH in ALS.

Fabry disease.

Fabry disease results from deficient activity of the enzyme α-galactosidase A and progressive lysosomal deposition of globotriaosylceramide (GL-3) in cells throughout the body. The main neurological presentations of Fabry disease patients are painful neuropathy, hypohidrosis, and stroke. Fabry neuropathy is characterized as a length-dependent peripheral neuropathy affecting mainly the small myelinated (Aδ) fibers and unmyelinated (C) fibers. Enzyme replacement therapy (ERT) has been shown to have some positive effects on the reduction of neuropathic pain, the improvement of detection threshold for thermal sensation, and sweat function. On the contrary, the effect of ERT on the central nervous system has not been established. Early initiation of ERT before irreversible organ failure is extremely important, and alternative therapeutic approaches are currently being explored. Heterozygotes suffer from peripheral neuropathy at a higher rate than previously shown, significant multisystemic disease, and severely decreased quality of life. As well as being carriers, heterozygotes also display symptoms of Fabry disease, and should be carefully monitored and given adequate therapy.

Intra-tissue localization of an antibacterial L-amino acid oxidase in the rockfish Sebastes schlegeli.

The rockfish Sebastes schlegeli skin mucus contains a potent antibacterial protein, SSAP (S. schlegeli antibacterial protein), a novel l-amino acid oxidase with strict substrate specificity that acts against water-borne Gram-negative bacteria. We previously demonstrated that SSAP distributes in the skin and gills. Here we investigated the intra-tissue localization of SSAP in the tissues by in situ hybridization. Skin and gill sections were hybridized with digoxigenin-conjugated SSAP-specific RNA probe. SSAP mRNA-positive cells located near the basal membrane of skin epidermis and the gill epithelium. Furthermore, skin section was analyzed by immunohistochemistry and reacted with anti-SSAP antiserum as a primary antibody. The mucus layer and mucous cells in the skin were immunopositive. Skin and gill extracts produced hydrogen peroxide, responsible for antibacterial activity, in the presence of l-lysine. These results suggested that SSAP functions locally as a humoral defense factor in S. schlegeli skin and gills and prevents pathogenic bacterial invasion.

Adult-onset multiple acyl CoA dehydrogenation deficiency associated with an abnormal isoenzyme pattern of serum lactate dehydrogenase.

We report a case of a 37 year-old male with multiple acyl-CoA dehydrogenation deficiency (MADD). The patient had suffered from exercise intolerance in his hip and thigh muscles for one year. Then, restriction of carbohydrates for a diet made his symptoms rapidly deteriorate. Blood test revealed compound heterozygosity for two novel missense mutations in the electron transfer flavoprotein dehydrogenase gene (ETFDH), and an abnormal LDH isoenzyme pattern: LDH-1 (60.0%) and LDH-2 (26.0%) predominated with abnormally elevated LDH-1/LDH-2 ratio (2.3), compared with muscle-derived LDH-5 (4.0%). Oral riboflavin treatment significantly improved his exercise intolerance and the LDH profile: LDH-1 (34.4%), LDH-2 (34.9%), LDH-5 (6.9%) and LDH-1/LDH-2 ratio (1.0). The abnormal LDH isoenzyme pattern may be one feature of adult-onset MADD selectively affecting type I muscle fibers with relatively high LDH-1 content.

Fabry disease.

PURPOSE OF REVIEW: This review discusses the literature on Fabry disease mainly in the domain of neurology with special attention to recent advancement. RECENT FINDINGS: Fabry neuropathy is known as a length-dependent peripheral neuropathy affecting mainly the small myelinated (Aδ) fibers and unmyelinated (C) fibers. Recently, concerning heterozygotes, it seems that they suffer from peripheral neuropathy at a higher rate than previously shown, significant multisystemic disease, and severely decreased quality of life. The existence of an atypical variant of Fabry disease with late-onset cerebrovascular disease (cerebrovascular variant) is now suggested, like the cardiac and renal variants of Fabry disease. Although enzyme replacement therapy (ERT) has been shown to have some positive effects on reduction of neuropathic pain, the improvement of detection threshold for thermal sensation and sweat function, the effect of ERT on the central nervous system has not been established. Gene replacement therapy, chemical chaperone therapy, and ERT using modified α-N-acetylgalactosaminidase are in progress, and induced pluripotent stem cells were generated from mouse models of Fabry disease. SUMMARY: Heterozygotes should be carefully monitored for precise estimation and adequate therapy. Early initiation of ERT before irreversible organ failure is most important, and alternative therapeutic approaches are currently being explored.

[A case of sensory ataxic neuropathy associated with asymptomatic primary biliary cirrhosis].

A 65-year-old woman showed progressive asymmetric sensory ataxic neuropathy (SAN) in upper limbs over 12 years, beginning with the onset of primary biliary cirrhosis (PBC). Nerve conduction study showed that sensory action potential was not evoked in upper limbs. Right superficial radial nerve biopsy showed the density of myelinated fibers was severely decreased with large-fiber predominance. Since Sjögren's syndrome (SjS) and paraneoplastic syndrome were denied, this type of neuropathy seems accompanied with asymptomatic PBC. Corticosteroid administration and intravenous immunoglobulin therapy failed to obtain any beneficial effect. The pathological mechanism is considered ganglionitis, which resembles that found in association with SjS. We should also consider PBC as the cause of SAN.

Iatrogenic neuropathies.

PURPOSE OF REVIEW: This review discusses the literature on peripheral neuropathy caused by medication-induced toxicity or immunological mechanism with special attention to recent advancements. RECENT FINDINGS: The number of reports of immune-mediated neuropathies associated with antitumor necrosis factor alpha (anti-TNFalpha) therapy is increasing. But long-term follow-up suggests that the cessation of anti-TNFalpha therapy is not always necessary. The cases of acute inflammatory demyelinating polyneuropathy induced by polyethylene glycol-interferon alpha-2a and of polyradiculoneuropathy induced by polyethylene glycol-interferon alpha-2b were reported for the first time, and the latter was associated with antiganglioside antibodies. The mechanism of chemotherapy-induced peripheral neuropathy is still in the process of being elucidated with the use of animal models or axonal excitability techniques. In the phase III Assessment of Proteasome Inhibitor for Extending Remissions trial, it proved that dose modification using a specific guideline improved bortezomib-induced peripheral neuropathy management. SUMMARY: Peripheral neuropathy can be associated with anti-TNFalpha therapy or interferon alpha therapy, and to the contrary, anti-TNFalpha therapy or interferon alpha therapy may have potential as a treatment option for a spectrum of immune-mediated neuropathy, similar to a double-edged sword. To take advantage of the effect of chemotherapy and to reduce neurotoxicity, a guideline of dose modification is useful.

A cross-sectional study for glucose intolerance of myotonic dystrophy.

We made a cross-sectional study to analyze glucose intolerance of myotonic dystrophy type 1 (DM1) with several examination including oral glucose tolerance test (OGTT), insulin tolerance test (ITT) and adiponectin. Ninety-five DM1 patients participated in this study. Health examination data from general people were used as controls. In DM1, homeostasis model assessment-insulin resistance (HOMA-IR) was higher than control even in the lowest fasting blood sugar (FBS) stage (<80 mg/dl) and insulin sensitivity assessed by ITT was low regardless of their FBS. Insulinogenic index of DM1 was positively correlated to HOMA-IR. Insulinogenic index and sum of IRI in OGTT were markedly elevated in the lowest FBS stage and declined along with elevation of FBS. Consequently, as many as 13.3% of DM1 patients with 90-110 mg/dl of FBS exhibited DM pattern, while only 1.9% in control. Adiponectin was higher in DM1 than control. Although age correlated with adiponectin in both control and DM1, its impact was stronger in DM1. DM1 predisposes insulin resistance and compensatory hyperinsulinemia exist even in patients with low FBS. We should pay attention to glucose intolerance of DM1 patients earlier than that of the general population. It seemed that 90 mg/dl of FBS is an important index as an indication of careful managements.

Gene expression and distribution of antibacterial L-amino acid oxidase in the rockfish Sebastes schlegeli.

Antibacterial factors in the epidermal mucus of fish have a potential importance in the first line of the host defense response to bacterial pathogens. We previously isolated a novel antibacterial protein termed SSAP (Sebastes schlegeli antibacterial protein) from the skin mucus of the rockfish S. schlegeli and identified it as a new member of the L-amino acid oxidase (LAO) family. In the present study, the localization of SSAP in S. schlegeli was investigated by reverse transcription (RT)-PCR, quantitative real time RT-PCR, Western blotting and measurements of LAO and antibacterial activities. SSAP mRNA was expressed dominantly in skin and gill and weakly in ovary or kidney as shown by RT-PCR and real time RT-PCR. The quantity of SSAP mRNA in skin varied among the individuals, ranging from 1.1 to 13.9 ng microg(-1) total RNA, although no relationship was found between the size of fish and gene expression. SSAP was exclusively detected in skin and gill by Western blotting using a specific anti-SSAP antiserum. In addition, the extracts of both tissues apparently showed LAO activity and antibacterial activity against Photobacterium damselae subsp. piscicida. This study demonstrates that SSAP is predominantly synthesized in skin and gill and probably functions as an antibacterial LAO in both tissues.

[Disturbance of jaw-opening due to extension of syringobulbia to the pons--a case report].

We report a patient with syringobulbia extending to the pons, who could not open his mouth widely. He had been involved in the traffic accident at 16 years of age. Since them he had suffered numbness in the left neck and arm. At age 30, he became unable to open the mouth widely with pain in the left jaw joint. He also noted dysphagia and tinnitus. Neurologically, there were vocal cord paresis, dysesthesia of the face, ageusia and cerebellar ataxia all on the left side. Brain MRI revealed syringobulbia which extended to the pons. Spinal MRI revealed syringomyelia through the entire spinal cord. The syrinx of the spinal cord seemed to connect with the brainstem lesion. EMG of the masticatory muscles revealed paradoxical activity in the left masticatory muscles. We concluded that disturbance of jaw-opening in this case was caused by syringobulbia, the lesion of which could involve masticatory central pattern generator in the brainstem.