Genetic analysis of IRF2BPL in a Taiwanese dystonia cohort: The genotype and phenotype correlation.

OBJECTIVE: IRF2BPL mutation has been associated with a rare neurodevelopmental disorder with abnormal movements, including dystonia. However, the role of IRF2BPL in dystonia remains elusive. We aimed to investigate IRF2BPL mutations in a Taiwanese dystonia cohort. METHODS: A total of 300 unrelated patients with molecularly unassigned isolated (n = 256) or combined dystonia (n = 44) were enrolled between January 2015 and July 2023. The IRF2BPL variants were analyzed based on whole exome sequencing. The in silico prediction of the identified potential pathogenic variant was performed to predict its pathogenicity. We also compared the clinical and genetic features to previous literature reports. RESULTS: We identified one adolescent patient carrying a de novo heterozygous pathogenic variant of IRF2BPL, c.379C>T (p.Gln127Ter), who presented with generalized dystonia, developmental regression, and epilepsy (0.33% of our dystonia cohort). This variant resides within the polyglutamine (poly Q) domain before the first PEST sequence block of the IRF2BPL protein, remarkably truncating the protein structure. Combined with other patients with IRF2BPL mutations in the literature (n = 60), patients with variants in the poly Q domain have a higher rate of nonsense mutations (p < 0.001) and epilepsy (p = 0.008) than patients with variants in other domains. Furthermore, as our index patient, carriers with substitutions before the first PEST sequence block have significantly older age of onset (p < 0.01) and higher non-epilepsy symptoms, including generalized dystonia (p = 0.003), and ataxia (p = 0.003). INTERPRETATION: IRF2BPL mutation is a rare cause of dystonia in our population. Mutations in different domains of IRF2BPL exhibit different phenotypes.

Unraveling the Pathogenetic Mechanisms Underlying the Association between Specific Mitochondrial DNA Haplogroups and Parkinson's Disease.

Variants of mitochondrial DNA (mtDNA) have been identified as risk factors for the development of Parkinson's disease (PD). However, the underlying pathogenetic mechanisms remain unclear. Cybrid models carrying various genotypes of mtDNA variants were tested for resistance to PD-simulating MPP+ treatment. The most resistant line was selected for transcriptome profiling, revealing specific genes potentially influencing the resistant characteristic. We then conducted protein validation and molecular biological studies to validate the related pathways as the influential factor. Cybrids carrying the W3 mtDNA haplogroup demonstrated the most resistance to the MPP+ treatment. In the transcriptome study, PPP1R15A was identified, while further study noted elevated expressions of the coding protein GADD34 across all cybrids. In the study of GADD34-related mitochondrial unfolding protein response (mtUPR), we found that canonical mtUPR, launched by the phosphate eIF2a, is involved in the resistant characteristic of specific mtDNA to MPP+ treatment. Our study suggests that a lower expression of GADD34 in the late phase of mtUPR may prolong the mtUPR process, thereby benefitting protein homeostasis and facilitating cellular resistance to PD development. We herein demonstrate that GADD34 plays an important role in PD development and should be further investigated as a target for the development of therapies for PD.

Miro1 improves the exogenous engraftment efficiency and therapeutic potential of mitochondria transfer using Wharton's jelly mesenchymal stem cells.

Mitochondria are important for maintaining cellular energy metabolism and regulating cellular senescence. Mitochondrial DNA (mtDNA) encodes subunits of the OXPHOS complexes which are essential for cellular respiration and energy production. Meanwhile, mtDNA variants have been associated with the pathogenesis of neurodegenerative diseases, including MELAS, for which no effective treatment has been developed. To alleviate the pathological conditions involved in mitochondrial disorders, mitochondria transfer therapy has shown promise. Wharton's jelly mesenchymal stem cells (WJMSCs) have been identified as suitable mitochondria donors for mitochondria-defective cells, wherein mitochondrial functions can be rescued. Miro1 participates in mitochondria trafficking by anchoring mitochondria to microtubules. In this study, we identified Miro1 over-expression as a factor that could help to enhance the efficiency of mitochondrial delivery. More specifically, we reveal that Miro1 over-expressed WJMSCs significantly improved intercellular communications, cell proliferation rates, and mitochondrial membrane potential, while restoring mitochondrial bioenergetics in mitochondria-defective fibroblasts. Furthermore, Miro1 over-expressed WJMSCs decreased rates of induced apoptosis and ROS production in MELAS fibroblasts; although, Miro1 over-expression did not rescue mtDNA mutation ratios nor mitochondrial biogenesis. This study presents a potentially novel therapeutic strategy for treating mitochondrial encephalomyopathy, lactic acidosis and stroke-like episodes (MELAS), and other diseases associated with dysfunctional mitochondria, while the pathophysiological relevance of our results should be further verified by animal models and clinical studies.

Blood neurofilament light chain as a surrogate marker for dystonia.

BACKGROUND AND PURPOSE: Dystonia is a heterogeneous movement disorder, and it remains unclear whether neurodegeneration is involved. Neurofilament light chain (NfL) is a biosignature of neurodegeneration. We aimed to investigate whether plasma NfL levels were elevated and associated with disease severity in patients with dystonia. METHOD: We enrolled 231 unrelated dystonia patients (isolated dystonia n = 203; combined dystonia n = 28) and 54 healthy controls from movement disorder clinics. Clinical severity was evaluated using the Fahn Marsden Dystonia Rating Scale, the Unified Dystonia Rating Scale, and the Global Dystonia Rating Scale. Blood NfL levels were measured by single-molecule array. RESULTS: Plasma NfL levels were significantly higher in those with generalized dystonia compared to those with focal dystonia (20.1 ± 8.8 vs. 11.7 ± 7.2 pg/mL; p = 0.01) or controls (p < 0.01), while the level was comparable between the focal dystonia group and controls (p = 0.08). Furthermore, the dystonia combined with parkinsonism group had higher NfL levels than the isolated dystonia group (17.4 ± 6.2 vs. 13.5 ± 7.5 pg/mL; p = 0.04). Notably, whole-exome sequencing was performed in 79 patients and two patients were identified as having likely pathogenic variants: one had a heterozygous c.122G>A (p.R41H) variant in THAP1 (DYT6) and the other carried a c.1825G>A (p.D609N) substitution in ATP1A3 (DYT12). No significant correlation was found between plasma NfL levels and dystonia rating scores. CONCLUSION: Plasma NfL levels are elevated in patients with generalized dystonia and dystonia combined with parkinsonism, suggesting that neurodegeneration is involved in the disease process of this subgroup of patients.

The Genetics of Primary Familial Brain Calcification: A Literature Review.

Primary familial brain calcification (PFBC), also known as Fahr's disease, is a rare inherited disorder characterized by bilateral calcification in the basal ganglia according to neuroimaging. Other brain regions, such as the thalamus, cerebellum, and subcortical white matter, can also be affected. Among the diverse clinical phenotypes, the most common manifestations are movement disorders, cognitive deficits, and psychiatric disturbances. Although patients with PFBC always exhibit brain calcification, nearly one-third of cases remain clinically asymptomatic. Due to advances in the genetics of PFBC, the diagnostic criteria of PFBC may need to be modified. Hitherto, seven genes have been associated with PFBC, including four dominant inherited genes (SLC20A2, PDGFRB, PDGFB, and XPR1) and three recessive inherited genes (MYORG, JAM2, and CMPK2). Nevertheless, around 50% of patients with PFBC do not have pathogenic variants in these genes, and further PFBC-associated genes are waiting to be identified. The function of currently known genes suggests that PFBC could be caused by the dysfunction of the neurovascular unit, the dysregulation of phosphate homeostasis, or mitochondrial dysfunction. An improved understanding of the underlying pathogenic mechanisms for PFBC may facilitate the development of novel therapies.

Telbivudine-Induced Myopathy: Clinical Features, Histopathological Characteristics, and Risk Factors.

BACKGROUND AND PURPOSE: Oral nucleos(t)ide analogs (NAs) are the mainstay treatment for chronic hepatitis B (CHB). Myotoxicity is an important extrahepatic effect related to NA treatment. Telbivudine is the NA for CHB that is frequently associated with muscle-related side effects. The risk factors for telbivudine-induced myopathy (TIM) are not yet clear. METHODS: This study characterized the clinical, magnetic resonance images (MRI), and pathological features of 12 TIM cases. A group of telbivudine-tolerant (TT) patients with CHB who received regular telbivudine treatment during the same period without the occurrence of myopathy was collected. Demographic and clinical factors were compared between the patients with TIM and the TT controls. Factors independently associated with TIM were identified using logistic regression analysis. RESULTS: The patients with TIM (males/females: 7/5, mean age: 57 years) developed myopathy after using telbivudine for a median period of 19.5 months. Muscle histopathology revealed abnormal proliferation, subsarcolemmal or sarcoplasmic accumulations, and ultrastructural defects of mitochondria. When compared with TT cases, patients with TIM had a lower estimated glomerular filtration rate and were more frequently positive for hepatitis B e antigen (HBeAg). CONCLUSIONS: Mitochondrial abnormalities are characteristic histopathological features, and impaired renal function and HBeAg positivity are risk factors for TIM. Telbivudine-induced mitochondrial dysfunction and immune activation related to mitochondrial damage and HBeAg serostatus changes may underlie TIM. Constant clinical surveillance of myopathy during telbivudine treatment is needed due to the significant latency of its development. Dose adjustment for impaired renal function does not eliminate the risk of TIM occurrence.

Higher prevalence of idiopathic normal pressure hydrocephalus-like MRI features in progressive supranuclear palsy: An imaging reminder of atypical parkinsonism.

OBJECTIVES: The classic triad of idiopathic normal pressure hydrocephalus (NPH) encompass gait disturbance, cognitive impairment, and urinary incontinence. These symptoms overlap with parkinsonism but with distinct treatment. Lacking applicable differentiation also hampers the prediction to therapeutic response. Here, we try to clarify this issue among different Parkinsonian syndromes and propose some innovative thinking while approaching a patient with parkinsonism and hydrocephalus concomitantly. METHODS: Twenty-four patients with clinical probable multiple system atrophy (MSA), 34 with probable progressive supranuclear palsy (PSP), and 58 with sex- and age-matched Parkinson's disease (PD) were enrolled. Evans' index (EI), callosal angle (CA), antero-posterior (AP) diameter of the midbrain, length of the midbrain tegmentum diameter (MBTegm ), and disproportionately enlarged subarachnoid space hydrocephalus (DESH) were evaluated using the conventional MRI. Logistic regression was applied to identify the independent variables in hydrocephalus. RESULTS: Patients with PSP had higher mean EI than those with MSA and PD. Around 38.2% of patients with PSP had accompanied hydrocephalus (EI > 0.3). Parkinsonism subtypes (PD, MSA, or PSP), AP diameter of the midbrain, and MBTegm were significantly different among patients with and without hydrocephalus. After regression analysis, parkinsonism subtype stood out to be the most key risk factor of hydrocephalus. The comparison between patients with PSP with and without hydrocephalus did not disclose specific clinical characteristics or risk factors. CONCLUSIONS: This study demonstrates that the presence of NPH-like MRI features is much higher in PSP patients, and this tendency is decided upon the determination of parkinsonism subtype. Sharing pathophysiological characteristics in these two diseases is implied. More diagnostic tools are needed to better differentiate the two diseases and decide the treatment. To closely observe hydrocephalic parkinsonism patients and well inform the possible limited shunting benefits if PSP core features appear, will be more pivotal and practical at present clinical practice.

Genetic analysis of IMPDH2 gene in Taiwanese patients with isolated or combined dystonia.

The inosine monophosphate dehydrogenase gene (IMPDH2) was recently reported as a novel gene associated with autosomal dominantly inherited dystonia. We investigated 245 Taiwanese patients with molecularly unassigned isolated or combined dystonia without features of neurodevelopmental disorders and found none had pathogenic variants. Our findings suggest that IMPDH2 may not play a major role in dystonia.

Iron Brain Menace: The Involvement of Ferroptosis in Parkinson Disease.

Parkinson disease (PD) is the second-most common neurodegenerative disease. The characteristic pathology of progressive dopaminergic neuronal loss in people with PD is associated with iron accumulation and is suggested to be driven in part by the novel cell death pathway, ferroptosis. A unique modality of cell death, ferroptosis is mediated by iron-dependent phospholipid peroxidation. The mechanisms of ferroptosis inhibitors enhance antioxidative capacity to counter the oxidative stress from lipid peroxidation, such as through the system xc-/glutathione (GSH)/glutathione peroxidase 4 (GPX4) axis and the coenzyme Q10 (CoQ10)/FSP1 pathway. Another means to reduce ferroptosis is with iron chelators. To date, there is no disease-modifying therapy to cure or slow PD progression, and a recent topic of research seeks to intervene with the development of PD via regulation of ferroptosis. In this review, we provide a discussion of different cell death pathways, the molecular mechanisms of ferroptosis, the role of ferroptosis in blood-brain barrier damage, updates on PD studies in ferroptosis, and the latest progress of pharmacological agents targeting ferroptosis for the intervention of PD in clinical trials.

Clinical and genetic characterization of a Taiwanese cohort with spastic paraparesis combined with cerebellar involvement.

Hereditary spastic paraplegias (HSPs) are a heterogeneous group of neurodegenerative disorders clinically characterized by progressive lower-limb spasticity. Cerebellar ataxia commonly co-occurs with complicated HSPs. HSP with concurrent cerebellar ataxia has significant clinical and genetic overlaps with hereditary cerebellar ataxia (HCA) and other inherited neurological diseases, adding to the challenge of planning genetic testing for the disease. In this study, we characterized clinical features of a cohort of 24 patients (male/female: 15/9) from 22 families who presented spastic paraparesis combined with cerebellar involvement, with a median disease onset age 20.5 (range 5-53) years. Aside from the core phenotype, 18 (75%) patients had additional neuropsychiatric and systemic manifestations. A stepwise genetic testing strategy stratified by mode of inheritance, distinct neuroimaging features (e.g., thin corpus callosum), population-specific prevalence and whole-exome sequencing was utilized to investigate the genetic etiology. Causative mutations in up to 10 genes traditionally related to HSP, HCA and other neurogenetic diseases (autosomal recessive spastic ataxia of Charlevoix-Saguenay, neurodegeneration with brain iron accumulation, and progressive encephalopathy with brain atrophy and thin corpus callosum) were detected in 16 (73%) of the 22 pedigrees. Our study revealed the genetic complexity of HSP combined with cerebellar involvement. In contrast to the marked genetic diversity, the functions of the causative genes are restricted to a limited number of physiological themes. The functional overlap might reflect common underlying pathogenic mechanisms, to which the corticospinal tract and cerebellar neuron circuits may be especially vulnerable.

Spontaneous splenic rupture as the first clinical manifestation of Niemann-Pick disease type B: A case report and review of the literature.

Splenomegaly is the most common phenotype for Niemann-Pick disease type B (NPD-B), an autosomal recessive lipid storage disease caused by deficiency of the lysosomal enzyme acid sphingomyelinase. Although a spleen of massive volume is common in NPD-B, splenic rupture in this disease is rarely reported. We describe a patient with NPD-B who initially presented with spontaneous splenic rupture. Microscopic examination of the spleen specimen revealed expansion of the red pulp by abundant foamy histiocytes. A literature review revealed that splenic rupture resulting from latent splenomegaly may occur in middle adulthood in a mild form of NPD-B associated with SMPD1 variants of lower pathogenicity. We suggest that unexplained splenomegaly or splenic rupture should raise the possibility of a lysosomal storage disease, including NPD. For patients with NPD-B, spleen size should be evaluated periodically, and the risk of splenic rupture should always be considered.

A Clinical and Integrated Genetic Study of Isolated and Combined Dystonia in Taiwan.

Dystonia is a clinically and genetically heterogeneous movement disorder. However, genetic causes of dystonia remain largely unknown in Asian subjects. To address this, we applied an integrated two-step approach that included gene dosage analysis and a next-generation sequencing panel containing 72 known genes causative for dystonia and related movement disorders to 318 Taiwanese patients with isolated or combined dystonia. Whole-genome sequencing was performed for one multiplex family with no known causative variant. The panel confirmed the genetic diagnosis in 40 probands (12.6%). A genetic diagnosis was more likely with juvenile onset compared with adult onset (24.2% vs 10.8%; P = 0.03) and those with combined features, especially with myoclonus, compared with isolated dystonia (35.3% vs 10.5%; P = 0.004). The most common causative genes were SGCE followed by GCH1, TH, CACNA1B, PRRT2, MR1, CIZ1, PLA2G6, and PRKN. Genetic causes were identified from single cases in TOR1A, TUBB4A, THAP1, ATP1A3, ANO3, GNAL, KMT2B, SLC6A3, ADCY5, CYP27A1, PANK2, C19orf12, and SPG11. The whole-genome sequencing analysis identified a novel intragenic deletion in OPHN1 in a multiplex family with X-linked dystonia and intellectual delay. Our findings delineate the genetic architecture and clinical spectrum of dystonia-causing pathogenic variants in an Asian population.

Investigating DYT1 in a Taiwanese dystonia cohort.

BACKGROUND/PURPOSE: A heterozygous three-nucleotide (GAG) in-frame deletion in the TOR1A gene causes the rare disease, dystonia (DYT1), which typically presents as focal limb dystonia during adolescence, then spreads to other limbs. This study investigated the frequency and clinical features of DYT1 in a Taiwanese dystonia cohort. METHODS: We performed targeted next generation sequencing in 318 patients with primary dystonia. We identified one DYT1 family with various types of dystonia, and we described the clinical presentations observed in this family during a 30-year follow-up. We compared the clinical characteristics to those reported in previous studies on DYT1 from 2000 to 2020. RESULTS: Among 318 patients, we identified only one DYT1 patient (0.3%) with an autosomal dominant family history of dystonia. The proband was a 43-year-old man that experienced progressive onset of focal lower limb dystonia from age 11 years. The disease spread caudal-rostrally to the upper limbs and cervical muscles. Prominent cervical dystonia was noted during follow-up, which was an atypical presentation of DYT1. Clinical assessments of other family members showed intrafamily variability. The proband's father and an affected sibling demonstrated only mild right-hand writer's cramp. A systematic review of previously reported DTY1 cases showed that Asian patients had a higher frequency of cervical dystonia (44.8%) than groups of Ashkenazi Jews (35%) and Non-Jewish Caucasians (30.5%) (P = 0.04). CONCLUSION: Our findings revealed that DYT1 is rare in a Taiwanese dystonia cohort. The presentation of marked cervical dystonia could be the main feature of Asian patients with DYT1.

Two Birds One Stone: The Neuroprotective Effect of Antidiabetic Agents on Parkinson Disease-Focus on Sodium-Glucose Cotransporter 2 (SGLT2) Inhibitors.

Parkinson's disease (PD) is the second most common neurodegenerative disease after Alzheimer's disease affecting more than 1% of the population over 65 years old. The etiology of the disease is unknown and there are only symptomatic managements available with no known disease-modifying treatment. Aging, genes, and environmental factors contribute to PD development and key players involved in the pathophysiology of the disease include oxidative stress, mitochondrial dysfunction, autophagic-lysosomal imbalance, and neuroinflammation. Recent epidemiology studies have shown that type-2 diabetes (T2DM) not only increased the risk for PD, but also is associated with PD clinical severity. A higher rate of insulin resistance has been reported in PD patients and is suggested to be a pathologic driver in this disease. Oral diabetic drugs including sodium-glucose cotransporter 2 (SGLT2) inhibitors, glucagon-like peptide-1 (GLP-1) receptor agonists, and dipeptidyl peptidase-4 (DPP-4) inhibitors have been shown to provide neuroprotective effects in both PD patients and experimental models; additionally, antidiabetic drugs have been demonstrated to lower incidence rates of PD in DM patients. Among these, the most recently developed drugs, SGLT2 inhibitors may provide neuroprotective effects through improving mitochondrial function and antioxidative effects. In this article, we will discuss the involvement of mitochondrial-related oxidative stress in the development of PD and potential benefits provided by antidiabetic agents especially focusing on sglt2 inhibitors.

Glucagon-Like Peptide-1 Receptor Agonist Ameliorates 1-Methyl-4-Phenyl-1,2,3,6-Tetrahydropyridine (MPTP) Neurotoxicity Through Enhancing Mitophagy Flux and Reducing α-Synuclein and Oxidative Stress.

Parkinson disease (PD) is the second most common neurodegenerative disease without known disease modification therapy to slow down disease progression. This disease has pathological features of Lewy bodies with α-synuclein aggregation being the major component and selective dopaminergic neuronal loss over the substantia nigra. Although the exact etiology is still unknown, mitochondrial dysfunction has been shown to be central in PD pathophysiology. Type 2 diabetes mellitus has recently been connected to PD, and anti-diabetic drugs, such as glucagon-like peptide-1 receptor agonists (GLP-1RAs), have been shown to possess neuroprotective effects in PD animal models. The GLP-1RA liraglutide is currently under a phase 2 clinical trial to measure its effect on motor and non-motor symptoms in PD patients. In this study, we used an acute 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) mouse model of PD to test the possible mechanism of the GLP-1RA liraglutide in the pathogenesis of PD. We show that the neurobehavioral and motor dysfunction caused by the mitochondrial complex I inhibitor, MPTP, can be partially reversed by liraglutide. The GLP-1RA can protect mice from apoptosis of substantia nigra neurons induced by MPTP. MPTP treatment led to imbalanced mitochondrial fusion and fission dynamics, altered mitochondrial morphology, impeded autophagy flux, increased α-synuclein accumulation, and elevated oxidative stress. Specifically, the normalizing of mitochondrial fusion-fission dynamic-related proteins and enhancement of autophagy flux after administration of liraglutide is associated with improving neuronal survival. This suggests that GLP-1RAs may provide potential beneficial effects for PD caused by mitochondrial dysfunction through improvement of mitochondrial morphology balance and enhancing damaged organelle degradation.

Clinical and genetic characterization of hereditary spastic paraplegia type 3A in Taiwan.

AIM: To investigate the clinical and genetic features of hereditary spastic paraplegia (HSP) type 3A (SPG3A) in Taiwan. METHODS: Mutational analysis of the ATL1 gene was performed for 274 unrelated Taiwanese HSP patients. The diagnosis of SPG3A was ascertained by the presence of a heterozygous pathogenic mutation in ATL1. The SPG3A patients received clinical, electrophysiological, and neuroimaging evaluations. Disease severity was assessed by using Spastic Paraplegia Rating Scale (SPRS) and disability score. Nineteen single nucleotide polymorphism (SNP) markers flanking ATL1 were genotyped for haplotype analysis of ATL1 p.R416C mutation. RESULTS: Eighteen SPG3A patients from 11 families were identified. They typically presented a pure form HSP phenotype with disease onset ranging from age 1-68 years. Five heterozygous ATL1 mutations were identified, including p.R239C, p.V253I, p.Y336H, p.P342R and p.R416C. ATL1 p.R416C was the most common mutation and presented in five SPG3A pedigrees. Haplotype analyses demonstrated a shared haplotype in the 12 individuals carrying a p.R416C allele. CONCLUSION: SPG3A accounts for 4% (11 out of 274) of HSP in the Taiwanese cohort. Patents with the ATL1 p.R416C mutation in Taiwan may descend from a common ancestor. This study defines the clinical and genetic features of SPG3A in Taiwan and provides useful information for the diagnosis and management, especially in patients of Han Chinese descent.

Brain hypoperfusion and nigrostriatal dopaminergic dysfunction in primary familial brain calcification caused by novel MYORG variants: case report.

BACKGROUND: Primary familial brain calcification (PFBC) is a rare inherited disease characterized by multiple calcified foci in the brain parenchyma. MYORG is the first gene found to be associated with autosomal recessive PFBC. The precise pathogenic mechanism of neurodegeneration in PFBC remains unclear. The clinical phenotypes of PFBC are variable, and there is no clear correlation between clinical manifestations and radiological and pathological features of calcification. CASE PRESENTATION: Two sisters in a Taiwanese family presented with young-onset Parkinsonism and multifocal dystonia. Their brain CTs showed multiple intracerebral calcifications. The genetic study detected two heterozygous novel variants, c.104 T > A (p.Met35Lys) and c.850 T > C (p.Cys284Arg) in the MYORG gene. In both patients, MR susceptibility weighted images revealed calcification of the deep medullary veins. Tc99m ECD SPECT demonstrated a significant decrease of tracer uptake in the brain cortex and subcortical gray matter. Tc99m TRODAT-1 SPECT revealed decreased tracer uptake in the bilateral striatum. CONCLUSION: Two novel MYORG variants were identified in Taiwanese family members presenting with PFBC. Abnormalities in the brain perfusion and dopamine transporter SPECTs suggest that cerebral ischemia due to extensive calcified vasculopathy, disruption of the basal ganglia-thalamo-cortical circuit, and nigrostriatal dopaminergic dysfunction are plausible pathogenic mechanisms of neurodegeneration in PFBC patients. Further investigation into the correlations between the pathogenicity-implicated imaging findings and the clinical phenotype are recommended.

Nutritional Status Associated with Molecular Biomarkers, Physiological Indices, and Clinical Severity in Parkinson's Disease Patients.

This study is intended to explore the associations between nutritional status and molecular biomarkers and the clinical severity of Parkinson's disease (PD), as well as to examine the differences in related factors between PD patients with normal nutrition and those with at risk for malnutrition. A cross-sectional assessment of 82 consecutive outpatients with PD was conducted using the mini nutritional assessment (MNA), Unified Parkinson's Disease Rating Scale (UPDRS), and the Hoehn and Yahr scale to determine the nutritional status, the clinical severity of PD, and the stage of the disease. Recordings of blood samples collected after 12 h of overnight fasting were also assessed in terms of serum levels of glycated hemoglobin (HbA1c), blood urea nitrogen (BUN), creatinine, cholesterol, high-density lipoprotein (HDL), low-density lipoprotein (LDL), hemoglobin (Hgb), folate, and vitamin B12. All participants were divided into normal nutrition and malnutrition risk groups via the MNA scores to compare the above-mentioned parameters. The results showed that the total MNA score was significantly correlated with some parts of the UPDRS scale (e.g., Sections 1 and 2) and the levels of HbAlc in PD patients and those with risk for malnutrition, with significantly lower weight and body mass index (BMI), and with lower levels of Hgb and HDL. Higher levels of cholesterol were observed in the malnutrition risk group as compared with the normal nutrition group. The findings suggest that the clinical severity of PD is associated with nutritional status. Body weight, BMI, and the levels of Hgb, cholesterol, and HDL could be, at least partially, important biological markers to monitor malnutrition and the progression of the disease.

Recessively-Inherited Adult-Onset Alexander Disease Caused by a Homozygous Mutation in the GFAP Gene.

BACKGROUND: Alexander disease (AxD) is an autosomal-dominant leukodystrophy caused by heterozygous mutations in the glial fibrillary acidic protein (GFAP) gene. OBJECTIVES: The objective of this report is to characterize the clinical phenotype and identify the genetic mutation associated with adult-onset AxD. METHODS: A man presented with progressive unsteadiness since age 16. Magnetic resonance imaging findings revealed characteristic features of AxD. The GFAP gene was screened, and a candidate variant was functionally tested to evaluate causality. RESULTS: A homozygous c.197G > A (p.Arg66Gln) mutation was found in the proband, and his asymptomatic parents were heterozygous for the same mutation. This mutation affected GFAP solubility and promoted filament aggregation. The presence of the wild-type protein rescued mutational effects, consistent with the recessive nature of this mutation. CONCLUSIONS: This study is the first report of AxD caused by a homozygous mutation in GFAP. The clinical implication is while examining patients with characteristic features on suspicion of AxD, GFAP screening is recommended even without a supportive family history. © 2020 International Parkinson and Movement Disorder Society.

Mitochondrial dysfunctions in leukoencephalopathy with brainstem and spinal cord involvement and lactate elevation (LBSL).

Several inherited human diseases have been linked to mitochondrial aminoacyl-tRNA synthetases (mtARSs). Leukoencephalopathy with brainstem and spinal cord involvement and lactate elevation (LBSL) is a leukodystrophy caused by mutations in the DARS2 gene which encodes mitochondrial aspartyl-tRNA synthetase. As mitochondrial ARSs are key components of the mitochondrial translation apparatus, we investigated the effects of DARS2 mutations on mitochondrial functions and mitochondrial morphology in an LBSL patient. In fibroblasts from the patient with LBSL, biosynthesis of respiratory chain complex proteins encoded by mitochondrial DNA was decreased, while those encoded by nuclear DNA were not. Cellular oxygen consumption rates and respiratory control ratio were decreased in the LBSL patient; in addition, fragmentation of mitochondria was increased, while their tubular elongation and interconnectivity were decreased. Taken together, these findings suggest that DARS2 mutations impair translations of mitochondrial DNA-encoded respiratory chain complex proteins, consequently causing dysfunction of cellular respiration and impediment of mitochondrial dynamics, which highlights the role of mtARSs in the maintenance of normal mitochondrial bioenergetics and dynamics.