BACKGROUND: Juvenile amyotrophic lateral sclerosis (JALS) is an uncommon form of amyotrophic lateral sclerosis whose age at onset (AAO) is defined as prior to 25 years. FUS mutations are the most common cause of JALS. SPTLC1 was recently identified as a disease-causative gene for JALS, which has rarely been reported in Asian populations. Little is known regarding the difference in clinical features between JALS patients carrying FUS and SPTLC1 mutations. This study aimed to screen mutations in JALS patients and to compare the clinical features between JALS patients with FUS and SPTLC1 mutations. METHODS: Sixteen JALS patients were enrolled, including three newly recruited patients between July 2015 and August 2018 from the Second Affiliated Hospital, Zhejiang University School of Medicine. Mutations were screened by whole-exome sequencing. In addition, clinical features such as AAO, onset site and disease duration were extracted and compared between JALS patients carrying FUS and SPTLC1 mutations through a literature review. RESULTS: A novel and de novo SPTLC1 mutation (c.58G>A, p.A20T) was identified in a sporadic patient. Among 16 JALS patients, 7/16 carried FUS mutations and 5/16 carried respective SPTLC1 , SETX , NEFH , DCTN1 , and TARDBP mutations. Compared with FUS mutation patients, those with SPTLC1 mutations had an earlier AAO (7.9 ± 4.6 years vs. 18.1 ± 3.9 years, P  < 0.01), much longer disease duration (512.0 [416.7-607.3] months vs. 33.4 [21.6-45.1] months, P  < 0.01), and no onset of bulbar. CONCLUSION Our findings expand the genetic and phenotypic spectrum of JALS and help to better understand the genotype-phenotype correlation of JALS.
Humans ; Amyotrophic Lateral Sclerosis/genetics* ; DNA Helicases/genetics* ; Genetic Association Studies ; Multifunctional Enzymes/genetics* ; Mutation/genetics* ; RNA Helicases/genetics* ; RNA-Binding Protein FUS/genetics* ; Serine C-Palmitoyltransferase/genetics* ; Child, Preschool ; Child ; Adolescent ; Young Adult

Child ; Humans ; Chromosomes, Human, Pair 16 ; Leukemia, Myeloid, Acute ; Neoplasms, Multiple Primary/genetics* ; Oncogene Proteins, Fusion/genetics* ; RNA-Binding Protein FUS/genetics* ; Sarcoma, Myeloid/genetics* ; Transcriptional Regulator ERG/genetics* ; Translocation, Genetic

Essential tremor (ET) is one of the most common movement disorders. Its clinical manifestations not only include typical kinetic and/or postural tremors, but also other non-motor symptoms such as cognitive dysfunction, sleep disturbance, and dysosmia. The exact etiology and pathogenesis of ET is still unknown. Approximately 60% of ET patients have a family history, and genetic factor plays an important role in the onset of the disease. Researchers have so far identified 3 genetic loci (ETM 1-3) through family studies, and proposed additional causative genes such as FUS, HTRA2, TENM4, NOS3 and susceptibility genes such as LINGO, SLC1A2, and GABA. This review focuses on the progress made in genetic research on ET.
Essential Tremor ; etiology ; genetics ; Genetic Predisposition to Disease ; Genetic Research ; High-Temperature Requirement A Serine Peptidase 2 ; genetics ; Humans ; Membrane Proteins ; genetics ; Nerve Tissue Proteins ; genetics ; RNA-Binding Protein FUS ; genetics

Amyotrophic lateral sclerosis (ALS) is a complex neurodegenerative disease with cellular and molecular mechanisms yet to be fully described. Mutations in a number of genes including SOD1 and FUS are associated with familial ALS. Here we report the generation of induced pluripotent stem cells (iPSCs) from fibroblasts of familial ALS patients bearing SOD1 and FUS mutations, respectively. We further generated gene corrected ALS iPSCs using CRISPR/Cas9 system. Genome-wide RNA sequencing (RNA-seq) analysis of motor neurons derived from SOD1 and corrected iPSCs revealed 899 aberrant transcripts. Our work may shed light on discovery of early biomarkers and pathways dysregulated in ALS, as well as provide a basis for novel therapeutic strategies to treat ALS.
Amyotrophic Lateral Sclerosis ; genetics ; metabolism ; therapy ; Cell Line ; Clustered Regularly Interspaced Short Palindromic Repeats ; Genetic Therapy ; Genome-Wide Association Study ; Humans ; Induced Pluripotent Stem Cells ; metabolism ; Mutation, Missense ; RNA-Binding Protein FUS ; genetics ; metabolism ; Superoxide Dismutase-1 ; genetics ; metabolism

Axonal transport of mitochondria is critical for neuronal survival and function. Automatically quantifying and analyzing mitochondrial movement in a large quantity remain challenging. Here, we report an efficient method for imaging and quantifying axonal mitochondrial transport using microfluidic-chamber-cultured neurons together with a newly developed analysis package named "MitoQuant". This tool-kit consists of an automated program for tracking mitochondrial movement inside live neuronal axons and a transient-velocity analysis program for analyzing dynamic movement patterns of mitochondria. Using this method, we examined axonal mitochondrial movement both in cultured mammalian neurons and in motor neuron axons of Drosophila in vivo. In 3 different paradigms (temperature changes, drug treatment and genetic manipulation) that affect mitochondria, we have shown that this new method is highly efficient and sensitive for detecting changes in mitochondrial movement. The method significantly enhanced our ability to quantitatively analyze axonal mitochondrial movement and allowed us to detect dynamic changes in axonal mitochondrial transport that were not detected by traditional kymographic analyses.
Animals ; Axonal Transport ; physiology ; Cerebral Cortex ; cytology ; metabolism ; Drosophila melanogaster ; cytology ; metabolism ; Embryo, Mammalian ; Gene Expression ; Lab-On-A-Chip Devices ; Microscopy, Confocal ; Mitochondria ; metabolism ; ultrastructure ; Motor Neurons ; metabolism ; ultrastructure ; Movement ; Mutation ; Primary Cell Culture ; RNA-Binding Protein FUS ; genetics ; metabolism ; Rats ; Rats, Sprague-Dawley ; Software

TAR DNA binding protein-43(TDP-43) and fused in sarcoma/translocated in liposarcoma protein (FUS/TLS) have been found to be associated with two neurodegenerative diseases - amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD). Mutations in TDP-43 and FUS/TLS lead to abnormal protein expressions, which result in altered RNA processing. The pathological changes of TDP-43 and FUS/TLS-associated ALS and FTD are similar. Although the interactions between ALS and FTD remain unknown, it is speculated that TDP-43 and FUS/TLS-associated neurodegenerative diseases may share similar pathogenesis.
Amyotrophic Lateral Sclerosis ; DNA-Binding Proteins ; genetics ; metabolism ; Frontotemporal Dementia ; Humans ; Mutation ; RNA Processing, Post-Transcriptional ; RNA-Binding Protein FUS ; genetics ; metabolism

Mutations in the Fused in sarcoma/Translated in liposarcoma gene (FUS/TLS, FUS) have been identified among patients with amyotrophic lateral sclerosis (ALS). FUS protein aggregation is a major pathological hallmark of FUS proteinopathy, a group of neurodegenerative diseases characterized by FUS-immunoreactive inclusion bodies. We prepared transgenic Drosophila expressing either the wild type (Wt) or ALS-mutant human FUS protein (hFUS) using the UAS-Gal4 system. When expressing Wt, R524S or P525L mutant FUS in photoreceptors, mushroom bodies (MBs) or motor neurons (MNs), transgenic flies show age-dependent progressive neural damages, including axonal loss in MB neurons, morphological changes and functional impairment in MNs. The transgenic flies expressing the hFUS gene recapitulate key features of FUS proteinopathy, representing the first stable animal model for this group of devastating diseases.
Aged ; Aging ; genetics ; metabolism ; pathology ; Amyotrophic Lateral Sclerosis ; genetics ; metabolism ; pathology ; Animals ; Animals, Genetically Modified ; Disease Models, Animal ; Drosophila melanogaster ; genetics ; metabolism ; Gene Expression ; Humans ; Microscopy, Electron, Scanning ; Motor Neurons ; metabolism ; pathology ; Mushroom Bodies ; metabolism ; pathology ; Mutant Proteins ; genetics ; metabolism ; Mutation ; Photoreceptor Cells, Invertebrate ; metabolism ; pathology ; Plasmids ; RNA-Binding Protein FUS ; genetics ; metabolism ; Recombinant Fusion Proteins ; genetics ; metabolism ; Retinal Degeneration ; pathology ; physiopathology ; Transfection

Amyotrophic lateral sclerosis (ALS) is a fatal disease characterized by the premature loss of motor neurons. While the underlying cellular mechanisms of neuron degeneration are unknown, the cytoplasmic aggregation of several proteins is associated with sporadic and familial forms of the disease. Both wild-type and mutant forms of the RNA-binding proteins FUS and TDP-43 accumulate in cytoplasmic inclusions in the neurons of ALS patients. It is not known if these so-called proteinopathies are due to a loss of function or a gain of toxicity resulting from the formation of cytoplasmic aggregates. Here we present a model of FUS toxicity using the yeast Saccharomyces cerevisiae in which toxicity is associated with greater expression and accumulation of FUS in cytoplasmic aggregates. We find that FUS and TDP-43 have a high propensity for co-aggregation, unlike the aggregation patterns of several other aggregation-prone proteins. Moreover, the biophysical properties of FUS aggregates in yeast are distinctly different from many amyloidogenic proteins, suggesting they are not composed of amyloid.
Amyotrophic Lateral Sclerosis ; metabolism ; pathology ; Cell Proliferation ; drug effects ; Cytoplasm ; drug effects ; metabolism ; DNA-Binding Proteins ; genetics ; metabolism ; Detergents ; pharmacology ; Humans ; Kinetics ; Peptides ; metabolism ; Prions ; chemistry ; metabolism ; Protein Binding ; drug effects ; Protein Multimerization ; drug effects ; Protein Structure, Quaternary ; Protein Transport ; RNA-Binding Protein FUS ; chemistry ; genetics ; metabolism ; Saccharomyces cerevisiae ; cytology ; drug effects ; genetics ; metabolism ; Saccharomyces cerevisiae Proteins ; chemistry ; metabolism

Mutations in the fused in sarcoma/translocated in liposarcoma (FUS/TLS) gene have been associated with amyotrophic lateral sclerosis (ALS). FUS-positive neuropathology is reported in a range of neurodegenerative diseases, including ALS and fronto-temporal lobar degeneration with ubiquitin-positive pathology (FTLDU). To examine protein aggregation and cytotoxicity, we expressed human FUS protein in yeast. Expression of either wild type or ALS-associated R524S or P525L mutant FUS in yeast cells led to formation of aggregates and cytotoxicity, with the two ALS mutants showing increased cytotoxicity. Therefore, yeast cells expressing human FUS protein recapitulate key features of FUS-positive neurodegenerative diseases. Interestingly, a significant fraction of FUS expressing yeast cells stained by propidium iodide were without detectable protein aggregates, suggesting that membrane impairment and cellular damage caused by FUS expression may occur before protein aggregates become microscopically detectable and that aggregate formation might protect cells from FUS-mediated cytotoxicity. The N-terminus of FUS, containing the QGSY and G rich regions, is sufficient for the formation of aggregates but not cytotoxicity. The C-terminal domain, which contains a cluster of mutations, did not show aggregation or cytotoxicity. Similar to TDP-43 when expressed in yeast, FUS protein has the intrinsic property of forming aggregates in the absence of other human proteins. On the other hand, the aggregates formed by FUS are thioflavin T-positive and resistant to 0.5% sarkosyl, unlike TDP-43 when expressed in yeast cells. Furthermore, TDP-43 and FUS display distinct domain requirements in aggregate formation and cytotoxicity.
Amino Acid Sequence ; Amino Acid Substitution ; DNA-Binding Proteins ; genetics ; metabolism ; Humans ; Mutation ; Neurodegenerative Diseases ; pathology ; Protein Structure, Tertiary ; RNA-Binding Protein FUS ; chemistry ; genetics ; metabolism ; Recombinant Proteins ; genetics ; metabolism ; toxicity ; Saccharomyces cerevisiae ; growth & development ; metabolism ; Sarcosine ; analogs & derivatives ; pharmacology ; Thiazoles ; metabolism

Many AML-associated chromosomal abnormalities, such as t(8;21), t(15;17), inv(16), t(9;11), t(9;22) and t(6;9) are well known. The chromosomal aberration of t(16;21)(p11;q22) in AML is rare and it is known to be associated with poor prognosis, young age (median age, 22 yr), and involvement of various subtypes of the French-American-British classification. We report here 2 AML patients with t(16;21)(p11;q22), proved by conventional cytogenetics and/or reverse transcription (RT)-PCR. Erythrophagocytosis by leukemic blasts was observed in both of the cases. One patient was a 24 yr-old male with acute myelomonocytic leukemia. His karyotype was 46,XY,t(16;21)(p11;q22),del(18)(p11.2) and RT-PCR revealed the TLS/FUS-ERG fusion transcripts. Although he received allogeneic peripheral blood stem cell transplantation after the first remission, he died 9 months after the initial diagnosis due to relapse of the disease and graft-versus-host disease. The other patient was a 72 yr-old male with acute myeloid leukemia without maturation. His karyotype was 45,XY,-16,add(21)(q22) and the presence of t(16;21)(p11;q22) was detected by RT-PCR. He was transferred to another hospital with no more follow-up. We suggest that the presence of t(16;21)(p11;q22) and/or TLS/FUS-ERG fusion transcripts has to be considered in cases of AML with erythrophagocytosis.
Aged ; Chromosomes, Human, Pair 16/*genetics ; Chromosomes, Human, Pair 22/*genetics ; Graft vs Host Disease/diagnosis ; Humans ; Karyotyping ; Leukemia, Myeloid, Acute/diagnosis/*genetics ; Male ; Oncogene Proteins, Fusion/*genetics ; RNA-Binding Protein FUS/*genetics ; Reverse Transcriptase Polymerase Chain Reaction ; *Translocation, Genetic ; Young Adult