Cerebral involvement in sitosterolemia.

BACKGROUND: Sitosterolemia, an autosomal recessive condition, is characterized by impaired metabolism of plant sterols. Clinical symptoms include skin xanthoma, premature atherosclerotic disease, arthritis, and unexplained hematological abnormalities. However, there is a dearth of studies on sitosterolemia-related brain damage. METHODS: This study focused on the family of two sitosterolemia patients who presented with severe hypercholesterolemia and xanthoma. Radiological examinations, biopsies, whole-exome sequencing (WES), and plant sterol tests were conducted. RESULTS: The index patient, a 66-year-old female, initially exhibited weakness in both lower limbs and later developed urinary and fecal incontinence. Neuroimaging showed that the falx of the brain had irregular fusiform thickening. Significant tissue edema was observed around the lesions in the bilateral frontal-parietal lobes. Pathological analysis of the biopsied brain lesion revealed extensive cholesterol crystal deposition and lymphocyte infiltration in the matrix. The index patient who experienced cerebral impairment and her sister both carried two compound heterozygous variants in ATP binding cassette transporter G5 (ABCG5). These included the nonsense variants NM_022436: c.751 C > T (p.Q251X) in exon 6 and NM_022436: c.1336 C > T (p.R446X) in exon 10. A notable increase in plant sterol levels was observed in the younger sister of the index patient. CONCLUSION: This study highlights a previously unreported neurological aspect of sitosterolemia. Imaging and pathology findings suggest that cholesterol crystals may be deposited in connective tissues such as the cerebral falx and pia mater through blood circulation.

Clinical and pathological characteristics of OPDM4 patients in advanced disease.

INTRODUCTION/AIMS: Oculopharyngodistal myopathy type 4 (OPDM4) arises from a CGG repeat expansion in the 5' UTR of the RILPL1 gene. Reported cases of OPDM4 have been limited. The aim of this study was to investigate the clinical and myopathological characteristics of OPDM4 patients with advanced disease. METHODS: We assessed a total of 8 affected and 12 unaffected individuals in an OPDM4 family with autosomal dominant inheritance. Muscle biopsy tissue from the proband underwent histological, enzyme histochemical, and immunohistochemical stains, and electron microscopy analysis. Whole exome sequencing and repeat primer PCR (RP-PCR) were conducted to investigate underlying variants. RESULTS: OPDM4 patients displayed a progressive disease course. Most experienced lower limb weakness and diminished walking ability in their 20s and 30s, followed by ptosis, ophthalmoplegia, swallowing difficulties, and dysarthria in their 30s to 50s, By their 50s to 70s, they became non-ambulatory. Muscle magnetic resonance imaging (MRI) of the proband in advanced disease revealed severe fatty infiltration of pelvic girdle and lower limb muscles. Biopsied muscle tissue exhibited advanced changes typified by adipose connective tissue replacement and the presence of multiple eosinophilic and p62-positive intranuclear inclusions. Immunopositivity for the intranuclear inclusions was observed with anti-glycine antibody and laboratory-made polyA-R1 antibody. RP-PCR unveiled an abnormal CGG repeat expansion in the 5' UTR of the RILPL1 gene. DISCUSSION: The clinical and radiological features in this family broaden the phenotypic spectrum of OPDM4. The presence of intranuclear inclusions in the proliferative adipose connective tissues of muscle biopsy specimens holds diagnostic significance for OPDM4 in advanced disease.

Comparison between MRI-negative and positive results and the predictors for a poor prognosis in patients with idiopathic acute transverse myelitis.

BACKGROUND: Idiopathic acute transverse myelitis (IATM) is a focal inflammatory disorder of the spinal cord that results in motor, sensory, and autonomic dysfunction. However, the comparative analysis of MRI-negative and MRI-positive in IATM patients were rarely reported. OBJECTIVES: The purpose of this study was to compare MRI-negative with MRI-positive groups in IATM patients, analyze the predictors for a poor prognosis, thus explore the relationship between MRI-negative and prognosis. METHODS: We selected 132 patients with first-attack IATM at the First Affiliated Hospital of Nanchang University from May 2018 to May 2022. Patients were divided into MRI-positive and MRI-negative group according to whether there were responsible spinal MRI lesions, and good prognosis and poor prognosis based on whether the EDSS score ≥ 4 at follow-up. The predictive factors of poor prognosis in IATM patients was analyzed by logistic regression models. RESULTS: Of the 132 patients, 107 first-attack patients who fulfilled the criteria for IATM were included in the study. We showed that 43 (40%) patients had a negative spinal cord MRI, while 27 (25%) patients were identified as having a poor prognosis (EDSS score at follow-up ≥ 4). Compared with MRI-negative patients, the MRI-positive group was more likely to have back/neck pain, spinal cord shock and poor prognosis, and the EDSS score at follow-up was higher. We also identified three risk factors for a poor outcome: absence of second-line therapies, high EDSS score at nadir and a positive MRI result. CONCLUSIONS: Compared with MRI-negative group, MRI-positive patients were more likely to have back/neck pain, spinal cord shock and poor prognosis, with a higher EDSS score at follow-up. The absence of second-line therapies, high EDSS score at nadir, and a positive MRI were risk factors for poor outcomes in patients with first-attack IATM. MRI-negative patients may have better prognosis, an active second-line immunotherapy for IATM patients may improve clinical outcome.

Efgartigimod for generalized myasthenia gravis: A multicenter real-world cohort study in China.

OBJECTIVE: Efgartigimod, a neonatal Fc receptor antagonist, facilitates antibody degradation including pathogenic IgGs. The ADAPT study demonstrated the tolerability and efficacy of efgartigimod in the treatment of generalized myasthenia gravis (gMG). However, very limited evidence is available for the Chinese population, and it remains inconclusive about which kind of patients are selected to preferentially receive efgartigimod in real-world settings. METHODS: This multicenter cohort study included gMG patients treated at 14 neuromuscular reference centers in China. The Myasthenia Gravis Activities of Daily Living (MG-ADL) score, immunosuppressants, and the incidence of treatment-emergent adverse events (TEAEs) were prospectively collected. RESULTS: Of the 1640 gMG admitted between September and December 2023, 61 (3.7%) received efgartigimod for at least one treatment cycle. Among them, 56 cases (92%) were anti-AChR antibody-positive, 4 were anti-MuSK antibody-positive, and 1 was seronegative. Thymoma-associated myasthenia gravis accounted for most cases (44%, 27 out of 61). The principal causes of efgartigimod initiation included MG acute exacerbation (MGAE) (48%, 29 out of 61) and myasthenic crisis (MC) (15%, 9 out of 61). Clinically meaningful improvement was rapidly achieved in 97% (58 out of 61) of patients at 1.3 ± 0.7 weeks. By week 12, the MG-ADL score reduced to 3.8 ± 4.1 (baseline:10.5 ± 5.2) for all participants, while it reduced to 4.0 ± 4.7 for MGAE and 3.8 ± 4.2 for MC, respectively. All but one TMG patient required no additional rescue therapies after efgartigimod initiation. 11.5% (7 out of 61) reported ≥1 TEAEs. INTERPRETATION: This multicenter cohort study demonstrated the efficacy of efgartigimod in rapid control of gMG. Patients with MGAE or MC would benefit from efgartigimod treatment.

Clinical and genetic characteristics of myotonia congenita in Chinese population.

Myotonia congenita (MC) is a rare hereditary muscle disease caused by variants in the CLCN1 gene. Currently, the correlation of phenotype-genotype is still uncertain between dominant-type Thomsen (TMC) and recessive-type Becker (BMC). The clinical data and auxiliary examinations of MC patients in our clinic were retrospectively collected. Electromyography was performed in 11 patients and available family members. Whole exome sequencing was conducted in all patients. The clinical and laboratory data of Chinese MC patients reported from June 2004 to December 2022 were reviewed. A total of 11 MC patients were included in the study, with a mean onset age of 12.64 ± 2.73 years. The main symptom was muscle stiffness of limbs. Warm-up phenomenon and percussion myotonia were found in all patients. Electromyogram revealed significant myotonic charges in all patients and two asymptomatic carriers, while muscle MRI and biopsy showed normal or nonspecific changes. Fourteen genetic variants including 6 novel variants were found in CLCN1. Ninety-eight Chinese patients were re-analyzed and re-summarized in this study. There were no significant differences in the demographic data, clinical characteristics, and laboratory findings between 52 TMC and 46 BMC patients. Among the 145 variants in CLCN1, some variants, including the most common variant c.892 G>A, could cause TMC in some families and BMC in others. This study expanded the clinical and genetic spectrum of Chinese patients with MC. It was difficult to distinguish between TMC and BMC only based on the clinical, laboratory, and genetic characteristics.

Encephalitis-like episodes with cortical edema and enhancement in patients with neuronal intranuclear inclusion disease.

OBJECTIVES: Neuronal intranuclear inclusion disease (NIID) exhibited significant clinical heterogeneities. However, the clinical features, radiographic changes, and prognosis of patients with encephalitis-like NIID have yet to be systematically elucidated. METHODS: Clinical data including medical history, physical examination, and laboratory examinations were collected and analyzed. Skin and sural nerve biopsies were conducted on the patient. Repeat-primed PCR (RP-PCR) and fluorescence amplicon length PCR (AL-PCR) were used to detect the expansion of CGG repeat. We also reviewed the clinical and genetic data of NIID patients with cortical enhancement. RESULTS: A 54-year-old woman presented with encephalitis-like NIID, characterized by severe headache and agitative psychiatric symptoms. The brain MRI showed cortical swelling in the temporo-occipital lobes and significant enhancement of the cortical surface and dura, but without hyperintensities along the corticomedullary junction on diffusion-weighted image (DWI). A biopsy of the sural nerve revealed a demyelinating pathological change. The intranuclear inclusions were detected in nerve and skin tissues using the p62 antibody and electron microscopy. RP-PCR and AL-PCR unveiled the pathogenic expansion of CGG repeats in the NOTCH2NLC gene. A review of the literature indicated that nine out of the 16 patients with cortical lesions and linear enhancement exhibited encephalitis-like NIID. CONCLUSION: This study indicated that patients with encephalitis-like NIID typically exhibited headache and excitatory psychiatric symptoms, often accompanied by cortical edema and enhancement of posterior lobes, and responded well to glucocorticoid treatment. Furthermore, some patients may not exhibit hyperintensities along the corticomedullary junction on DWI, potentially leading to misdiagnosis.

Homozygous variant in COQ7 causes autosomal recessive hereditary spastic paraplegia.

Biallelic mutations in the coenzyme Q7 (COQ7) encoding gene were recently identified as a genetic cause of distal hereditary motor neuropathy. Here, we explored the clinical, electrophysiological, pathological, and genetic characteristics of a Chinese patient with spastic paraplegia associated with recessive variants in COQ7. This patient carried a novel c.322C>A (p.Pro108Thr) homozygous variant. Sural biopsy revealed mild mixed axonal and demyelinating degeneration. Immunoblotting showed a significant decrease in the COQ7 protein level in the patient's fibroblasts. This study confirmed that COQ7 variant as a genetic cause of HSP, and further extended spastic paraplegia to the phenotypic spectrum of COQ7-related disorders.

Clinical characteristics of autoimmune encephalitis with co-existence of multiple anti-neuronal antibodies.

BACKGROUND: An increasing number of cases of autoimmune encephalitis (AE) with co-existing multiple anti-neuronal antibodies have been reported in recent years. However, the clinical significance of the concurrent presence of multiple anti-neuronal antibodies in patients with AE remains unclear. METHODS: We retrospectively enrolled AE patients with multiple anti-neuronal antibodies treated at our center between August 2019 and February 2022. We also reviewed cases reported in multiple literature databases. Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guideline was followed on selection process. And then the clinical and laboratory data of these cases were collected for review and summary. RESULTS: A total of 83 AE cases with multiple antibodies (9 cases from our center and 74 cases from the literatures reviewed) were identified. In our center, nine patients presented with encephalitis symptoms, clinically characterized as disturbed consciousness, seizures, cognitive impairment, and psychiatric disorders. Of the 83 cases, 73 cases had co-existence of 2 types of antibodies, 8 cases had 3 types, and 2 cases had 4 types. Thirty-nine cases (39/83, 46.9%) were confirmed or suspected of also having a tumor, of which the most common was lung cancer (28/83, 33.7%). Partial or complete recovery was achieved in 57 cases (57/83, 68.6%), while 26 cases (26/83, 31.3%) died during treatment or follow-up. CONCLUSIONS: AE with co-existing multiple anti-neuronal antibodies is a specific subgroup, that is increasingly recognized in clinical practice. The co-existence of multiple anti-neuronal antibodies has a major impact on clinical features, disease progression, and prognosis.

Pathologic changes in neuronal intranuclear inclusion disease are linked to aberrant FUS interaction under hyperosmotic stress.

CGG repeat expansion in NOTCH2NLC is the genetic cause of neuronal intranuclear inclusion disease (NIID). Previous studies indicated that the CGG repeats can be translated into polyglycine protein (N2CpolyG) which was toxic to neurons by forming intranuclear inclusions (IIs). However, little is known about the factors governing polyG IIs formation as well as its molecular pathogenesis. Considering that neurogenetic disorders usually involve interactions between genetic and environmental stresses, we investigated the effect of stress on the formation of IIs. Our results revealed that under hyperosmotic stress, N2CpolyG translocated from the cytoplasm to the nucleus and formed IIs in SH-SY5Y cells, recapitulating the pathological hallmark of NIID patients. Furthermore, N2CpolyG interacted/ co-localized with an RNA-binding protein FUS in the IIs of cellular model and NIID patient tissues, thereby disrupting stress granule formation in cytoplasm under hyperosmotic stress. Consequently, dysregulated expression of microRNAs was found both in NIID patients and cellular model, which could be restored by FUS overexpression in cultured cells. Overall, our findings indicate a mechanism of stress-induced pathological changes as well as neuronal damage, and a potential strategy for the treatment of NIID.

Weaning difficulty after severe pneumonia in adult-onset mitochondrial myopathy with A3243G mutation in the mitochondrial tRNA gene: A case report.

Background: Mitochondrial myopathy is a group of diseases caused by abnormal mitochondrial structure or function. The mitochondrial myopathy impacts muscles of the whole body and exhibits variable symptoms. Respiratory muscle deficits deteriorate pulmonary function in patients with severe pneumonia. Case presentation: We report the case of a male patient with severe pneumonia-induced respiratory failure. He was abnormally dependent invasive ventilator-assisted ventilation after his condition had improved. Then we found abnormal ventilator waveform and a decline in muscle strength of him. Mitochondrial myopathy was ultimately confirmed by muscle pathological biopsy and body fluid genetic testing. Vitamin B complex, coenzyme Q10, Neprinol AFD, l-arginine, and MITO-TONIC were used to improve mitochondrial function and muscle metabolism. After treatment, discomfort associated with chest tightness, fatigue, cough, and sputum disappeared, and the patient was discharged. Conclusion: This case presented an uncommon cause of difficult weaning and extubation-acute onset of mitochondrial myopathy. Muscle biopsy and genetic testing of body fluid are essential for diagnosing mitochondrial myopathy. The A3243G mutation in the MT-TL1 gene of mitochondrial DNA contributes to pathogenesis of this case.

Knockout of Rnf213 Ameliorates Cerebral Ischemic-reperfusion Injury by Inhibiting Neuronal Apoptosis Through the Akt/GSK-3ß/ß-catenin/Bcl-2 Pathway.

Previous studies by us and others have shown that RING finger protein 213 (RNF213) is associated with cerebrovascular disease and systemic vasculopathy. Indeed, Rnf213 mRNA expression is increased in cerebral ischemia reperfusion injury (CIRI). The purpose of the present study was to investigate the role of Rnf213 in CIRI. Using the middle cerebral artery occlusion (MCAO) model, we confirmed that the expression of RNF213 protein was significantly upregulated in neurons in the ischemic penumbra. Rnf213 knockout mice were successfully generated using CRISPR/Cas9 technology. According to TTC staining and Bederson neurological scale, removal of Rnf213 decreased brain infarct volume and improved neurological deficit score, although the restoration of cerebral blood flow after MCAO was similar in WT and Rnf213-/- mice. In addition, the levels of p-Akt, p-GSK-3ß, ß-catenin and Bcl-2 were significantly increased 24 h after MCAO in the ischemic penumbra of the Rnf213-/- mice compared to WT mice, indicating that Rnf213 removal may ameliorate neuronal apoptosis by regulating the Akt/GSK-3ß/ß-catenin/Bcl-2 signaling pathway. Taken together, our study reveals that Rnf213 regulates neuronal apoptosis in CIRI, therefore impacting on brain infarct volume in brain ischemia.

Skin biopsy and neuronal intranuclear inclusion disease.

Neuronal intranuclear inclusion disease (NIID) is a rare neurodegenerative disease with variable clinical phenotypes. There is a considerable delay in the definite diagnosis, which primarily depends on postmortem brain pathological examination. Although CGG repeat expansion in the 5'-untranslated region of NOTCH2NLC has been identified as a disease-associated variant, the pathological diagnosis is still required in certain NIID cases. Intranuclear inclusions found in the skin tissue of patients with NIID dramatically increased its early detection rate. Skin biopsy, as a minimally invasive method, has become widely accepted as a routine examination to confirm the pathogenicity of the repeat expansion in patients with suspected NIID. In addition, the shared developmental origin of the skin and nerve system provided a new insight into the pathological changes observed in patients with NIID. In this review, we systematically discuss the role of skin biopsy for NIID diagnosis, the procedure of skin biopsy, and the pathophysiological mechanism of intranuclear inclusion in the skin.

The serum IgG antibody level as a biomarker for clinical outcome in patients with cerebral sparganosis after treatment.

Introduction: Cerebral sparganosis is a rare parasitic infection of the brain tissue. The remission of MRI change and clinical symptom has been used to evaluate the therapeutic effect. However, there is no study to correlate the serum IgG antibody level of sparganum to the prognosis of disease after treatment. Methods: 87 patients with cerebral sparganosis were collected from three medical centers. Clinical symptoms and MRI changes were evaluated at 12 months after initial treatment, and serum IgG antibody level of sparganum was evaluated at 2, 6, and 12 months after treatment. The positive cut-off value was based on 2.1 times the optical density (OD) of negative control. The index value was defined as the sample OD divided by the cut-off value. Results: Among the 87 patients after treatment, 71 patients had good clinical outcomes, and 16 had poor clinical outcomes. The area under the curve (AUC) showed that the index value measured at 12 months after treatment had the best prediction effect, with a value of 2.014. In the good-outcome group, the index values were less than 2.014 in all 71 patients, and only 8 patients had mildly enhanced residual lesions on MRI. In the poor-outcome group, the index values were more than 2.014 in all 16 patients, and all patients still showed significantly enhanced lesions on MRI. Compared with poor-outcome patients, only 2 patients with good outcomes had disease recurrence after treatment. Discussion: This study provided evidence that the serum IgG antibody level of sparganum was a promising biomarker to evaluate the prognosis of patients with cerebral sparganosis after treatment.

Internal Carotid Artery Aneurysm Presenting as Lower Cranial Nerve Palsies.

The signs of lower cranial nerve palsies are rare and are often caused by tumors. A 49-year-old woman was admitted to our hospital with progressive right-sided atrophy of the tongue, sternocleidomastoid and trapezius, dysarthria, and dysphagia for 3 years. Brain magnetic resonance imaging revealed a circular lesion adjacent to the lower cranial nerves. Cerebral angiography confirmed that the lesion was an unruptured aneurysm in the C1 segment of the right internal carotid artery. After endovascular treatment, the symptoms of this patient had partially improved.

Risk factors of vestibular migraine-related brain white matter lesions.

OBJECTIVE AND PURPOSE: Migraine is related to white matter lesions (WMLs), and attack frequency and duration in migraine patients are thought to increase WMLs. However, the relationship between vestibular migraine (VM) and WMLs remains unclear. This study explored the risk factors for WMLs in VM patients and provided a basis for the prevention of WMLs in VM patients. METHODS: A large single-center cross-sectional study of patients with VM was conducted. None of the patients had comorbidities, such as hypertension and diabetes, or adverse lifestyle habits (smoking and drinking). All patients were divided into WML + and WML- groups after assessment of WMLs using magnetic resonance imaging (MRI). After collecting the patient's detailed medical history, statistical analysis was performed. RESULTS: In univariate analysis, the frequency of vertigo was statistically significant between the WML + and WML- groups. However, there was no significant difference in other clinical features. Multivariate regression analysis found that the frequency of vertigo (OR 2.399; 95% CI 1.014-5.679; p = 0.046) was an independent risk factor for WMLs. High frequency of vertigo episodes showed more pronounced risk factors (OR 9.607; 95% CI 1.061-87.014; p = 0.044). CONCLUSION: These results substantiate that vertigo frequency is an independent risk factor for WMLs in VM. A high frequency of vertigo episodes is more likely to be associated with WMLs than a low frequency. These results suggest a possible approach to the prevention of WMLs in VM patients.

Distal hereditary neuropathy associated with a novel mutation in alanyl-aminoacyl-tRNA synthetase.

To report a new genetic cause of distal hereditary motor neuropathy (dHMN), which is likely associated with worsening during pregnancy. We collected the clinical data of a patient with severe weakness of the lower limbs induced by repeated pregnancy and performed relevant experimental examinations, including neuromuscular electrophysiological examination, neuromuscular biopsy, and genetic testing. The patient reported weakness of the right lower extremity after delivery of the first child. Initially, the right foot was weak during lifting, and symptoms gradually progressed to weakness when landing on the toe during walking. She then developed weakness of the right lower extremity and thinning of the right leg. After an interval of 2.5 years, after delivery of the second child, her left lower extremity developed asthenia, with the same symptoms as previously reported for the right lower extremity. Subsequently, weakness of both lower extremities became progressively worse, and she developed difficulty sitting up, getting out of bed, and walking. Physical examination showed that both upper limb vertebral tracts were damaged and both lower extremity motor nerves were damaged. Electrophysiology suggested motor axonal neurogenic damage. Brain magnetic resonance imaging demonstrated leukodystrophy. Sural nerve biopsy suggested mild axonal damage. Skeletal muscle biopsy suggested neurogenic skeletal muscle damage. Genetic testing suggested that there was a heterozygous mutation at the shear site of the AARS gene. An AARS mutation may cause dHMN associated with pyramidal tract signs.

Urine cytological study in patients with clinicopathologically confirmed neuronal intranuclear inclusion disease.

Objective: The diagnosis of neuronal intranuclear inclusion disease (NIID) is currently based on CGG repeat expansion in the 5'UTR of the NOTCH2NLC gene, or p62-positive intranuclear inclusions in skin biopsy. The purpose of this study is to explore the value of non-invasive pathological findings in urine sediment cells from NIID patients. Materials and methods: Ten patients with clinically suspected NIID were enrolled for skin biopsy and gene screening. Morning urine (500 ml) was collected from each patient, and cell sediment was obtained by centrifugation. Urine cytology, including Giemsa staining, p62 immunostaining, and electron microscopic examination, were conducted on cell sediment. Results: The main clinical symptoms of 10 patients included episodic disturbance of consciousness, cognitive impairment, tremor, limb weakness, and so on. Cerebral MRI showed that 9 patients had linear DWI high signal in the corticomedullary junction. Genetic testing found that the number of CGG repeat ranged from 96 to 158 in the NOTCH2NLC gene. Skin biopsy revealed that all patients showed p62-positive intranuclear inclusions in 18.5 ± 6.3% of the duct epithelial cells of sweat gland. In contrast, urine sediment smears revealed that only 3 patients had p62 positive intranuclear inclusions in 3.5 ± 1.2% of the sedimentary cells. Ultrastructural examinations showed that intranuclear inclusions were also identified in the cell sediment of the 3 patients. Conclusion: Urine cytology may be a new and non-invasive pathological diagnosis technique for some NIID patients, although the positive rate is not as high as that of skin biopsy, which is a sensitive and reliable pathological method for NIID.

FUS Mutation Causes Disordered Lipid Metabolism in Skeletal Muscle Associated with ALS.

Amyotrophic lateral sclerosis (ALS) is a devastating neurodegenerative disease characterized by dysfunction of the upper and lower motor neurons resulting in muscle weakness and wasting. Recently, several studies on ALS patients and ALS animal models indicated that intramuscular toxicity played a role in ALS disease progression; however, the mechanisms driving this are unknown. In this study, we explored the possible dysfunction of lipid metabolism in myocytes associated with ALS. Initially, skeletal muscle from 41 ALS patients, as well as 53 non-ALS control subjects, was investigated, and we identified that lipid droplet accumulation in the muscle fibers of ALS patients was significantly increased, especially in patients with FUS mutations. A myoblast (C2C12) cell line expressing mutant FUS (FUS-K510Q) was able to induce lipid droplet accumulation and mitochondrial dysfunction. Consistently, transgenic flies expressing FUS-K510Q under a muscle-specific driver showed elevated triglyceride levels in the flight muscles, as well as locomotor defects. Biochemical analysis of C2C12 cells and fly muscle tissues showed upregulation of PLIN2, and downregulation of ATGL and CPT1A, indicating inhibition of lipolysis and fatty acid ß-oxidation in muscle cells with FUS mutations. Our study provided a potential explanation for the pathogenesis associated with lipid droplets accumulating in skeletal muscle in ALS. Our data also suggested that disordered lipid metabolism and mitochondrial dysfunction play a crucial role in intramuscular toxicity in ALS.

The polyG diseases: a new disease entity.

Recently, inspired by the similar clinical and pathological features shared with fragile X-associated tremor/ataxia syndrome (FXTAS), abnormal expansion of CGG repeats in the 5' untranslated region has been found in neuronal intranuclear inclusion disease (NIID), oculopharyngeal myopathy with leukoencephalopathy (OPML), and oculopharyngodistal myopathy (OPDMs). Although the upstream open reading frame has not been elucidated in OPML and OPDMs, polyglycine (polyG) translated by expanded CGG repeats is reported to be as a primary pathogenesis in FXTAS and NIID. Collectively, these findings indicate a new disease entity, the polyG diseases. In this review, we state the common clinical manifestations, pathological features, mechanisms, and potential therapies in these diseases, and provide preliminary opinions about future research in polyG diseases.