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Mutations in optineurin (OPTN) have been identified in a small proportion of sporadic and familial amyotrophic lateral sclerosis (ALS) cases. Recent evidences suggest that OPTN would be involved in not only the pathophysiological mechanisms of motor neuron death of ALS but also myofiber degeneration of sporadic inclusion body myositis. However, the detailed role of OPTN in muscle remains unclear. Initially, we showed that OPTN expression levels were significantly increased in the denervated muscles of mice, suggesting that OPTN may be involved in muscle homeostasis. To reveal the molecular role of OPTN in muscle atrophy, we used cultured C2C12 myotubes treated with tumor necrosis factor-like inducer of apoptosis (TWEAK) as an in vitro model of muscle atrophy. Our data showed that OPTN had no effect on the process of muscle atrophy in this model. On the other hand, we found that myogenic differentiation was affected by OPTN. Immunoblotting analysis showed that OPTN protein levels gradually decreased during C2C12 differentiation. Furthermore, OPTN knockdown inhibited C2C12 differentiation, accompanied by reduction of mRNA and protein expression levels of myogenin and MyoD. These findings suggested that OPTN may have a novel function in muscle homeostasis and play a role in the pathogenesis of neuromuscular diseases.

Background Both fragile X-associated tremor/ataxia syndrome (FXTAS) and late-onset neuronal intranuclear inclusion disease (NIID) show CGG/GGC trinucleotide repeat expansions. Differentiating these diseases are difficult because of the similarity in their clinical and radiological features. It is unclear that skin biopsy can distinguish NIID from FXTAS. We performed a skin biopsy in an FXTAS case with cognitive dysfunction and peripheral neuropathy without tremor, which was initially suspected to be NIID. Case presentation The patient underwent neurological assessment and examinations, including laboratory tests, electrophysiologic test, imaging, skin biopsy, and genetic test. A brain MRI showed hyperintensity lesions along the corticomedullary junction on diffusion-weighted imaging (DWI) in addition to middle cerebellar peduncle sign (MCP sign). We suspected NIID from the clinical picture and the radiological findings, and performed a skin biopsy. The skin biopsy specimen showed ubiquitin- and p62-positive intranuclear inclusions, suggesting NIID. However, a genetic analysis for NIID using repeat-primed polymerase chain reaction (RP-PCR) revealed no expansion detected in the Notch 2 N-terminal like C (NOTCH2NLC) gene. We then performed genetic analysis for FXTAS using RP-PCR, which revealed a repeat CGG/GGC expansion in the FMRP translational regulator 1 (FMR1) gene. The number of repeats was 83. We finally diagnosed the patient with FXTAS rather than NIID. Conclusions For the differential diagnosis of FXTAS and NIID, a skin biopsy alone is insufficient; instead, genetic analysis, is essential. Further investigations in additional cases based on genetic analysis are needed to elucidate the clinical and pathological differences between FXTAS and NIID.

Parkinson’s disease (PD) is caused by a combination of genetic and environmental factors. Notably, genetic risk factors vary according to ethnicity and geographical regions, and few studies have analyzed the frequency of PD causative genes in Japanese patients. Therefore, we performed genetic analyses of Japanese patients with PD. We recruited 221 participants, including 26 patients with familial PD. Genetic risk factors were evaluated by target sequencing and gene dosage analysis. We detected the genetic risk factors in 58 cases (26.2%) and classified patients into three groups to clarify the differences in genetic risk factors by age at onset (AAO). The early-onset group (AAO

In amyotrophic lateral sclerosis (ALS), early diagnosis is essential for both current and potential treatments. To find a supportive approach for the diagnosis, we constructed an artificial intelligence‐based prediction model of ALS using induced pluripotent stem cells (iPSCs). Images of spinal motor neurons derived from healthy control subject and ALS patient iPSCs were analyzed by a convolutional neural network, and the algorithm achieved an area under the curve of 0.97 for classifying healthy control and ALS. This prediction model by deep learning algorithm with iPSC technology could support the diagnosis and may provide proactive treatment of ALS through future prospective research. ANN NEUROL 2021, Deep LearningとALS iPS細胞を用いた疾患予測テクノロジー --人工知能のALS検知・診断への応用--. 京都大学プレスリリース. 2021-02-24., Deep learning amyotrophic lateral sclerosis by taking pictures. 京都大学プレスリリース. 2021-02-24.

We here report an autopsy case of familial amyotrophic lateral sclerosis (ALS) with p.Arg487His mutation in the valosin-containing protein (VCP) gene (VCP), in which upper motor neurons (UMNs) were predominantly involved. Moreover, our patient developed symptoms of frontotemporal dementia later in life and pathologically exhibited numerous phosphorylated transactivation response DNA-binding protein of 43 kDa (p-TDP-43)-positive neuronal cytoplasmic inclusions and short dystrophic neurites with a few lentiform neuronal intranuclear inclusions, sharing the features of frontotemporal lobar degeneration with TDP-43 pathology type A pattern. A review of previous reports of ALS with VCP mutations suggests that our case is unique in terms of its UMN-predominant lesion pattern and distribution of p-TDP-43 pathology. Thus, this case report effectively expands the clinical and pathological phenotype of ALS in patients with a VCP mutation.

Degeneration of neuromuscular junctions and axons is considered an important aspect of the pathomechanism of amyotrophic lateral sclerosis (ALS). However, a mechanism including the role of transactive response DNA-binding protein 43 (TDP-43) in axons has not been pathologically clarified.To identify and characterize the histopathology of peripheral axons in the skeletal muscle of patients with ALS.This study comprised 2 parts: a postmortem case-control study and a retrospective population-based cohort study with a minimum of 1 year of follow-up. Patients in the cohort study were enrolled from January 1, 2004, to September 30, 2019. The postmortem study included patients with sporadic ALS (SALS) with TDP-43 pathology and control patients with non-ALS disease. The cohort study enrolled patients without a family history of ALS or other neuromuscular disease and those not diagnosed with a muscle disease at biopsy. Patients were excluded if their clinical records were not screened after biopsy, if they were diagnosed with a muscular disease, and if they were harboring known causative genes of ALS. Data were collected between September 2019 and June 2021 and analyzed in June 2021.Muscle biopsy or postmortem muscle tissue examination.Clinical information and muscle pathological characteristics.A total of 10 patients with autopsy-confirmed SALS (mean [SD] age at death, 76.1 [8.5] years; 8 men [80%]) exhibited axonal phosphorylated TDP-43 (pTDP-43)-positive accumulations in intramuscular nerve bundles; the 12 control patients without ALS did not. Among the 114 patients in the cohort study (mean [SD] age, 62.3 [16.1] years; 76 men [67%]), 71 patients (62.3%) exhibited intramuscular nerve bundles; 43 (37.7%) did not. Among those who exhibited pTDP-43-positive intramuscular nerve bundles, 33 patients (22 men [66.7%]; mean [SD] age, 65.2 [15.6] years) were later diagnosed with ALS. The other 38 patients (26 men [68.4%]; mean [SD] age, 59.3 [18.0] years) showed no pTDP-43-positive bundles and did not develop ALS. Among those without evident nerve bundles (28 men [65.1%]; mean [SD] age, 61.3 [15.3] years), 3 were later diagnosed with ALS. Among patients with ALS in the biopsy cohort, 9 with pTDP-43-positive bundles showed only lower motor neuron symptoms at biopsy.Results of this dual case-control and retrospective cohort study suggest that axonal pTDP-43 accumulations may be characteristic for patients with ALS. As such findings precede clinical fulfillment of the Gold Coast criteria, TDP-43 in nerve bundles may be a novel diagnostic biomarker for ALS.

Spinocerebellar ataxia type 14 (SCA14) is an autosomal dominant SCA caused by variants of the PRKCG encoding protein kinase C gamma (PKCγ). Although the toxic gain-of-function mechanism is the main cause of SCA14, its molecular pathophysiology remains unclear. To elucidate the molecular pathogenesis of SCA14, we analyzed two families with the variants in PRKCG. Clinical symptoms and neurological findings of two Japanese families were evaluated by neurologists. Exome sequencing was performed using the BGI platform. GFP-tagged PRKCGs harboring the identified variants were transfected into the HeLa cells, and aggregation of PKCγ was analyzed using confocal laser microscopy. Solubility of PKCγ was evaluated by assessing the proportion of insoluble fraction present in1% Triton-X. Patients in family 1 presented with only cerebellar atrophy without ataxia; however, patients in family 2 exhibited cerebellar ataxia, dystonia, and more severe cerebellar atrophy than those in family 1. Exome sequencing identified two novel missense variants of PRKCG:c.171 G C,p.W57C (family 1), and c.400 T C,p.C134R (family 2). Both the mutant PKCγ aggregated in the cytoplasm. Although the solubility of PKCγ of the C134R variant was lower than that of the wild-type, PKCγ of W57C retained its solubility. In conclusion, we identified two novel variants of PRKCG. The difference in severity between the two families may be due to the difference in solubility changes observed between the two variants. Decreased solubility of the PKCγ may play an important role in the pathogenesis of SCA14.

Key points Some ion channels are known to behave as inductors and make up the parallel resonant circuit in the plasma membrane of neurons, which enables neurons to respond to current inputs with a specific frequency (so-called 'resonant properties'). Here, we report that heterologous expression of mouse Kv11 voltage-dependent K+ channels generate resonance and oscillation at depolarized membrane potentials in HEK293 cells; expressions of individual Kv11 subtypes generate resonance and oscillation with different frequency properties. Kv11.3-expressing HEK293 cells exhibited transient conductance changes that opposed the current changes induced by voltage steps; this probably enables Kv11 channels to behave like an inductor. The resonance and oscillation of inferior olivary neurons were impaired at the resting membrane potential in Kv11.3 knockout mice. This study helps to elucidate basic ion channel properties that are crucial for the frequency responses of neurons. Abstract The plasma membranes of some neurons preferentially respond to current inputs with a specific frequency, and output as large voltage changes. This property is called resonance, and is thought to be mediated by ion channels that show inductor-like behaviour. However, details of the candidate ion channels remain unclear. In this study, we mainly focused on the functional roles of Kv11 potassium (K+ ) channels, encoded by ether-a-go-go-related genes, in resonance in mouse inferior olivary (IO) neurons. We transfected HEK293 cells with long or short splice variants of Kv11.1 (Merg1a and Merg1b) or Kv11.3, and examined membrane properties using whole-cell recording. Transfection with Kv11 channels reproduced resonance at membrane potentials depolarized from the resting state. Frequency ranges of Kv11.3-, Kv11.1(Merg1b)- and Kv11.1(Merg1a)-expressing cells were 2-6 Hz, 2-4 Hz, and 0.6-0.8 Hz, respectively. Responses of Kv11.3 currents to step voltage changes were essentially similar to those of inductor currents in the resistor-inductor-capacitor circuit. Furthermore, Kv11 transfections generated membrane potential oscillations. We also confirmed the contribution of HCN1 channels as a major mediator of resonance at more hyperpolarized potentials by transfection into HEK293 cells. The Kv11 current kinetics and properties of Kv11-dependent resonance suggested that Kv11.3 mediated resonance in IO neurons. This finding was confirmed by the impairment of resonance and oscillation at -30 to -60 mV in Kcnh7 (Kv11.3) knockout mice. These results suggest that Kv11 channels have important roles in inducing frequency-dependent responses in a subtype-dependent manner from resting to depolarized membrane potentials.

Spinocerebellar ataxia (SCA) 42 is caused by a mutation in CACNA1G, which encodes the low voltage-gated calcium channel CaV3.1 (T-type). Patients with SCA42 exhibit a pure form of cerebellar ataxia. We encountered a patient with the p.Arg1715His mutation, suffering from intractable resting tremor, particularly head tremor. This symptom improved with the administration of low-dose of zonisamide (ZNS), a T-type calcium channel blocker effective for treating Parkinson’s disease and epilepsy. Previous electrophysiological studies showed that the voltage dependence of this mutant CaV3.1 was shifted toward the positive potential. This abnormal shift was considered a factor related to disease onset and symptoms. In this study, we performed whole-cell recordings of GFP-expressing HEK293T cells that expressed wild-type or mutant CaV3.1 and investigated the changes in the abnormal shift of voltage dependence of the mutant CaV3.1. The results showed that ZNS in an amount equivalent to the patient’s internal dose significantly ameliorated the abnormal shift in the mutant CaV3.1, giving values close to those in the wild-type. On the other hand, ZNS did not affect the voltage dependence of wild-type CaV3.1. Because CaV3.1 is known to be involved in tremogenesis, modulation of the voltage dependence of mutant CaV3.1 by ZNS might have contributed to improvement in the intractable tremor of our patient with SCA42. Moreover, efonidipine, another T-type calcium channel blocker, had no effect on tremors in our patient with SCA42 and did not improve the abnormal shift in the voltage dependence of the mutant CaV3.1. This indicates that ZNS is distinct from other T-type calcium channel blockers in terms of modulation of the voltage dependence of the mutant CaV3.1.

Primary familial brain calcification (PFBC) is a hereditary neurological disorder characterized by idiopathic calcification of the bilateral basal ganglia and other areas of the brain. MYORG has been identified as the first causative gene of autosomal recessive PFBC in Chinese families. There have been several reports of PFBC associated with MYORG (MYORG-PFBC) in individuals of Middle Eastern, European, and Latin American ancestry but to date, there have been no reported Japanese cases. We report the first Japanese case of MYORG-PFBC. The patient was a 43-year-old Japanese woman who experienced mild headaches and cerebellar ataxia including dysarthria. Computed tomography showed calcification in the cerebral white matter, basal ganglia, cerebellum, and brainstem. Using exome sequencing, we identified a homozygous variant in the MYORG gene (NM_020702.4: c.794C>T,p.Thr265Met). Our patient presented dysarthria and extensive calcification affecting the pons, which are specific features of MYORG-PFBC. We report clinical symptoms and imaging findings of a case with p.Thr265Met variant.

Spinocerebellar ataxia (SCA) is a genetically heterogeneous disease characterized by cerebellar ataxia. Many causative genes have been identified to date, the most common etiology being the abnormal expansion of repeat sequences, and the mutation of ion channel genes also play an important role in the development of SCA. Some of them encode calcium and potassium channels. However, due to limited reports about potassium genes in SCA, we screened 192 Japanese individuals with dominantly inherited SCA who had no abnormal repeat expansions of causative genes for potassium channel mutations (KCNC3 for SCA13 and KCND3 for SCA19/SCA22) by target sequencing. As a result, two variants were identified from two patients: c.1973G>A, p.R658Q and c.1018G>A, p.V340M for KCNC3, and no pathogenic variant was identified for KCND3. The newly identified p.V340M exists in the extracellular domain, and p.R658Q exists in the intracellular domain on the C-terminal side, although most of the reported KCNC3 mutations are present at the transmembrane site. Adult-onset and slowly progressive cerebellar ataxia are the main clinical features of SCA13 and SCA19 caused by potassium channel mutations, which was similar in our cases. SCA13 caused by KCNC3 mutations may present with deep sensory loss and cognitive impairment in addition to cerebellar ataxia. In this study, mild deep sensory loss was observed in one case. SCA caused by potassium channel gene mutations is extremely rare, and more cases should be accumulated in the future to elucidate its pathogenesis due to channel dysfunction.

The Research Institute for Radiation Biology and Medicine (RIRBM) of Hiroshima University has been conducting a cohort study of atomic bomb survivors (ABS). Cohort members include those who were issued an Atomic Bomb Health Handbook from the Hiroshima local government. A series of dosimetry systems for the ABS were developed at RIRBM to evaluate the health effects associated with radiation exposure. The framework used to estimate individual doses in our dosimetry systems for ABS is mainly based on the Dosimetry System 86, and its revisions developed by the Radiation Effect Research Foundation. This article describes the design and computational principles for the dosimetry systems in RIRBM and the history of the revisions, from the first version of the system, ABS93D, to the most recent version, ABS16D. We then provide a perspective for further improvement and application of the dosimetry system.

We previously showed that optineurin (OPTN) mutations lead to the development of amyotrophic lateral sclerosis. The association between OPTN mutations and the pathogenesis of amyotrophic lateral sclerosis remains unclear. To investigate the mechanism underlying its pathogenesis, we generated Optn knockout mice. We evaluated histopathological observations of these mice and compared with those of OPTN- amyotrophic lateral sclerosis cases to investigate the mechanism underlying the pathogenesis of amyotrophic lateral sclerosis caused by OPTN mutations. The Optn (−/−) mice presented neuronal autophagic vacuoles immunopositive for charged multivesicular body protein 2b, one of the hallmarks of granulovacuolar degenerations, in the cytoplasm of spinal cord motor neurons at the age of 8 months and the OPTN- amyotrophic lateral sclerosis case with homozygous Q398X mutation. In addition, Optn (−/−) mice showed TAR-DNA binding protein 43/sequestosome1/p62 -positive cytoplasmic inclusions and the clearance of nuclear TAR-DNA binding protein 43. The axonal degeneration of the sciatic nerves was observed in Optn (−/−) mice. However, we could not observe significant differences in survival time, body weight, and motor functions, at 24 months. Our findings suggest that homozygous OPTN deletion or mutations might result in autophagic dysfunction and TAR-DNA binding protein 43 mislocalization, thereby leading to neurodegeneration of motor neurons. These findings indicate that the Optn (−/−) mice recapitulate both common and specific pathogenesis of amyotrophic lateral sclerosis associated with autophagic abnormalities. Optn (−/−) mice could serve as a mouse model for the development of therapeutic strategies.

Key points Some ion channels are known to behave as inductors and make up the parallel resonant circuit in the plasma membrane of neurons, which enables neurons to respond to current inputs with a specific frequency (so‐called ‘resonant properties’).Here, we report that heterologous expression of mouse Kv11 voltage‐dependent K+ channels generate resonance and oscillation at depolarized membrane potentials in HEK293 cells; expressions of individual Kv11 subtypes generate resonance and oscillation with different frequency properties.Kv11.3‐expressing HEK293 cells exhibited transient conductance changes that opposed the current changes induced by voltage steps; this probably enables Kv11 channels to behave like an inductor.The resonance and oscillation of inferior olivary neurons were impaired at the resting membrane potential in Kv11.3 knockout mice.This study helps to elucidate basic ion channel properties that are crucial for the frequency responses of neurons. Abstract The plasma membranes of some neurons preferentially respond to current inputs with a specific frequency, and output as large voltage changes. This property is called resonance, and is thought to be mediated by ion channels that show inductor‐like behaviour. However, details of the candidate ion channels remain unclear. In this study, we mainly focused on the functional roles of Kv11 potassium (K+) channels, encoded by ether‐á‐go‐go‐related genes, in resonance in mouse inferior olivary (IO) neurons. We transfected HEK293 cells with long or short splice variants of Kv11.1 (Merg1a and Merg1b) or Kv11.3, and examined membrane properties using whole‐cell recording. Transfection with Kv11 channels reproduced resonance at membrane potentials depolarized from the resting state. Frequency ranges of Kv11.3‐, Kv11.1(Merg1b)‐ and Kv11.1(Merg1a)‐expressing cells were 2–6 Hz, 2–4 Hz, and 0.6–0.8 Hz, respectively. Responses of Kv11.3 currents to step voltage changes were essentially similar to those of inductor currents in the resistor–inductor–capacitor circuit. Furthermore, Kv11 transfections generated membrane potential oscillations. We also confirmed the contribution of HCN1 channels as a major mediator of resonance at more hyperpolarized potentials by transfection into HEK293 cells. The Kv11 current kinetics and properties of Kv11‐dependent resonance suggested that Kv11.3 mediated resonance in IO neurons. This finding was confirmed by the impairment of resonance and oscillation at –30 to –60 mV in Kcnh7 (Kv11.3) knockout mice. These results suggest that Kv11 channels have important roles in inducing frequency‐dependent responses in a subtype‐dependent manner from resting to depolarized membrane potentials., Key points Some ion channels are known to behave as inductors and make up the parallel resonant circuit in the plasma membrane of neurons, which enables neurons to respond to current inputs with a specific frequency (so‐called ‘resonant properties’).Here, we report that heterologous expression of mouse Kv11 voltage‐dependent K+ channels generate resonance and oscillation at depolarized membrane potentials in HEK293 cells; expressions of individual Kv11 subtypes generate resonance and oscillation with different frequency properties.Kv11.3‐expressing HEK293 cells exhibited transient conductance changes that opposed the current changes induced by voltage steps; this probably enables Kv11 channels to behave like an inductor.The resonance and oscillation of inferior olivary neurons were impaired at the resting membrane potential in Kv11.3 knockout mice.This study helps to elucidate basic ion channel properties that are crucial for the frequency responses of neurons.

Primary familial brain calcification (PFBC) is a hereditary neurological disorder characterized by idiopathic calcification of the bilateral basal ganglia and other areas of the brain. MYORG has been identified as the first causative gene of autosomal recessive PFBC in Chinese families. There have been several reports of PFBC associated with MYORG (MYORG-PFBC) in individuals of Middle Eastern, European, and Latin American ancestry but to date, there have been no reported Japanese cases. We report the first Japanese case of MYORG-PFBC. The patient was a 43-year-old Japanese woman who experienced mild headaches and cerebellar ataxia including dysarthria. Computed tomography showed calcification in the cerebral white matter, basal ganglia, cerebellum, and brainstem. Using exome sequencing, we identified a homozygous variant in the MYORG gene (NM_020702.4: c.794CT,p.Thr265Met). Our patient presented dysarthria and extensive calcification affecting the pons, which are specific features of MYORG-PFBC. We report clinical symptoms and imaging findings of a case with p.Thr265Met variant.

A sophisticated and delicate balance between bone resorption by osteoclasts and bone formation by osteoblasts regulates bone metabolism. Optineurin (OPTN) is a gene involved in primary open-angle glaucoma and amyotrophic lateral sclerosis. Although its function has been widely studied in ophthalmology and neurology, recent reports have shown its possible involvement in bone metabolism through negative regulation of osteoclast differentiation. However, little is known about the role of OPTN in osteoblast function. Here, we demonstrated that OPTN controls not only osteoclast but also osteoblast differentiation. Different parameters involved in osteoblastogenesis and osteoclastogenesis were assessed in Optn-/- mice. The results showed that osteoblasts from Optn-/- mice had impaired alkaline phosphatase activity, defective mineralized nodules, and inability to support osteoclast differentiation. Moreover, OPTN could bind to signal transducer and activator of transcription 1 (STAT1) and regulate runt-related transcription factor 2 (RUNX2) nuclear localization by modulating STAT1 levels in osteoblasts. These data suggest that OPTN is involved in bone metabolism not only by regulating osteoclast function but also by regulating osteoblast function by mediating RUNX2 nuclear translocation via STAT1.

Amyotrophic lateral sclerosis (ALS) primarily affects upper and lower motor neurons. Phosphorylated trans-activation response DNA-binding protein of 43 kDa (TDP-43) inclusion bodies are reportedly a pathological hallmark of sporadic ALS. Here, we present an atypical case of sporadic ALS that progressed very slowly, persisted for 19 years, and clinically appeared to only affect the lower motor neurons; however, upper motor neuron degeneration was detected at autopsy. Furthermore, no inclusion bodies positive for phosphorylated TDP-43, ubiquitin, fused in sarcoma, or superoxide dismutase-1 were detected in the central nervous system. We performed exome-sequencing data analysis but found no genetic disorders. This was therefore an unusual case of lower motor neuron-predominant ALS without TDP-43 pathology or known gene-disease associations. We also reviewed autopsied ALS cases that progressed slowly and had no phosphorylated TDP-43 or ubiquitin-positive inclusions and present the clinicopathological features of such cases. Based on these results, there may be a sporadic ALS subgroup that progresses slowly and shows no accumulation of phosphorylated TDP-43.

Amyotrophic lateral sclerosis (ALS) is a fatal neurodegenerative disease caused by the loss of both upper and lower motor neurons. Approximately 10% of patients with ALS have a family history of the disease, and 22 genes have already been reported to be implicated in ALS.1 In previous reports, some of the genes implicated in ALS were associated with visual dysfunctions; however, no cases have yet reported patients presenting clinically both ALS and ocular abnormalities.1 Recently, a large case-controlled genome-wide association study (GWAS) of ALS revealed cilia and flagella-associated protein 410 ( CFAP410 ), previously called as C21orf2 .2 CFAP410 is causative for axial spondylometaphyseal dysplasia (SMDAX), which presents with retinitis pigmentosa (RP), and retinal dystrophy (RD) with or without macular staphyloma.3 However, no hereditary ALS cases have yet reported CFAP410 variants. In this letter, we provide the first description of siblings with RP and ALS with the causative CFAP410 mutation. They showed RP until their fourth decade and muscle weakness of the extremities started more than 10 years after the diagnosis of RP. The pedigree chart of the affected family is presented in figure 1A. Their parents (I-1 and I-2) were consanguineous and neurologically healthy. Figure 1 (A) Pedigree chart of the affected family. Shaded boxes represent affected members. Symbols having diagonal lines represent deceased individuals. Unaffected family members exhibited no abnormalities during their medical examinations. (B) Sanger sequencing revealed that the patients had exon 4 of a CFAP410 homozygous variant (c.319T>C, p.Y107H) and that the non-affected sibling had a heterozygous variant of CFAP410 . (C) Heterozygous CFAP410 variants of amyotrophic lateral sclerosis (ALS) (black) were previously detected except for exon 2. On the other hand, causative …

Aggressive periodontitis causes rapid periodontal tissue destruction and is a disease that occurs at a young age and runs in the patient’s family. Here, we revealed a heterozygous A116V missense mutation in the gene encoding monocyte to macrophage differentiation associated 2 (MMD2) protein in a Japanese family with aggressive periodontitis and neutropenia. Analyses of patients’ peripheral blood revealed a low number of neutrophils but abundant quantity of CD34+hematopoietic stem and progenitor cells (HSPCs). Moreover, mutantMmd2mice showed severe alveolar bone loss and neutropenia. In patients and mutantMmd2mice, differentiation of HSPCs into granulocytes was also impeded, and their granulocytes were functionally impaired. Taken together, A116V mutation inMMD2gene induced mild neutropenia and slightly limited the immune defense response. Our studies suggested that aggressive periodontitis in association with A116VMMD2mutation constitutes a new immune system defect that belongs to the same spectrum of severe congenital neutropenia.

Spinocerebellar ataxia (SCA) is a genetically heterogeneous disease characterized by cerebellar ataxia. Many causative genes have been identified to date, the most common etiology being the abnormal expansion of repeat sequences, and the mutation of ion channel genes also play an important role in the development of SCA. Some of them encode calcium and potassium channels. However, due to limited reports about potassium genes in SCA, we screened 192 Japanese individuals with dominantly inherited SCA who had no abnormal repeat expansions of causative genes for potassium channel mutations (KCNC3 for SCA13 and KCND3 for SCA19/SCA22) by target sequencing. As a result, two variants were identified from two patients: c.1973GA, p.R658Q and c.1018GA, p.V340M for KCNC3, and no pathogenic variant was identified for KCND3. The newly identified p.V340M exists in the extracellular domain, and p.R658Q exists in the intracellular domain on the C-terminal side, although most of the reported KCNC3 mutations are present at the transmembrane site. Adult-onset and slowly progressive cerebellar ataxia are the main clinical features of SCA13 and SCA19 caused by potassium channel mutations, which was similar in our cases. SCA13 caused by KCNC3 mutations may present with deep sensory loss and cognitive impairment in addition to cerebellar ataxia. In this study, mild deep sensory loss was observed in one case. SCA caused by potassium channel gene mutations is extremely rare, and more cases should be accumulated in the future to elucidate its pathogenesis due to channel dysfunction.

BackgroundTheTWNKgene encodes the twinkle protein, which is a mitochondrial helicase for DNA replication. The dominantTWNKvariants cause progressive external ophthalmoplegia with mitochondrial DNA deletions, autosomal dominant 3, while the recessive variants cause mitochondrial DNA depletion syndrome 7 and Perrault syndrome 5. Perrault syndrome is characterized by sensorineural hearing loss in both males and females and gonadal dysfunction in females. Patients with Perrault syndrome may present early-onset cerebellar ataxia, whereas middle-age-onset cerebellar ataxia caused byTWNKvariants is rare.Case presentationA Japanese female born to consanguineous parents presented hearing loss at age 48, a staggering gait at age 53, and numbness in her distal extremities at age 57. Neurological examination revealed sensorineural hearing loss, cerebellar ataxia, decreased deep tendon reflexes, and sensory disturbance in the distal extremities. Laboratory tests showed no abnormal findings other than a moderate elevation of pyruvate concentration levels. Brain magnetic resonance imaging revealed mild cerebellar atrophy. Using exome sequencing, we identified a homozygousTWNKvariant (NM_021830: c.1358G>A, p.R453Q).ConclusionsTWNKvariants could cause middle-age-onset cerebellar ataxia. Screening forTWNKvariants should be considered in cases of cerebellar ataxia associated with deafness and/or peripheral neuropathy, even if the onset is not early.

Background The coexistence of distinct neurodegenerative diseases in single cases has recently attracted greater attention. The phenotypic co-occurrence of progressive supranuclear palsy (PSP) and amyotrophic lateral sclerosis (ALS) has been documented in several cases. That said, the clinicopathological comorbidity of these two diseases has not been demonstrated. Case presentation A 77-year-old man presented with gait disturbance for 2 years, consistent with PSP with progressive gait freezing. At 79 years old, he developed muscle weakness compatible with ALS. The disease duration was 5 years after the onset of PSP and 5 months after the onset of ALS. Neuropathological findings demonstrated the coexistence of PSP and ALS. Immunohistochemical examination confirmed 4-repeat tauopathy, including globose-type neurofibrillary tangles, tufted astrocytes, and oligodendroglial coiled bodies as well as TAR DNA-binding protein 43 kDa pathology in association with upper and lower motor neuron degeneration. Immunoblotting showed hyperphosphorylated full-length 4-repeat tau bands (64 and 68 kDa) and C-terminal fragments (33 kDa), supporting the diagnosis of PSP and excluding other parkinsonian disorders, such as corticobasal degeneration. Genetic studies showed no abnormalities in genes currently known to be related to ALS or PSP. Conclusions Our case demonstrates the clinicopathological comorbidity of PSP and ALS in a sporadic patient. The possibility of multiple proteinopathies should be considered when distinct symptoms develop during the disease course. Electronic supplementary material The online version of this article (10.1186/s12883-019-1402-7) contains supplementary material, which is available to authorized users.

ObjectiveTo determine the genetic underpinnings of slowly progressive spinocerebellar ataxia, autosomal recessive (SCAR), we performed exome analysis and examined the relationship between clinical severity and functional change induced by the mutation.MethodsHomozygosity fingerprinting and exome sequencing were performed to identify causative mutations in 2 consanguineous families. We assessed the expression of D-bifunctional protein (DBP) and the amount of dimerized DBP in fibroblasts by immunoblot and quantitative reverse transcription PCR. The pathogenicity of the mutation was evaluated using the Combined Annotation-Dependent Depletion (CADD) scores; these results were compared with the scores of previously reported mutations.ResultsWe identified a homozygous mutation as causative of middle age–onset SCAR: p.Ala175Thr, which is located in HSD17B4 that encodes peroxisomal DBP. The patients developed cerebellar ataxia, and the subsequent progression was slow. The symptoms presented were milder than those in previously reported cases. The messenger RNA expression levels were normal, but protein levels were diminished. Dimerization of DBP was also reduced. The CADD score of the identified mutation was lower than those of previously reported mutations.ConclusionsThis is the report of middle age–onset DBP deficiency. Residual functional DBP caused relatively mild symptoms in the affected patients, i.e., slowly progressive ataxia and hearing loss. This study broadens the scope of DBP deficiency phenotypes and indicates that CADD scores may be used to estimate the severity of DBP deficiencies.

Heart disease (HD) mortality is the second leading cause of death in Japan. The HD mortality risk among Atomic bomb survivors is slightly positive but shows a statistically significant dose-response relationship with initial radiation dose, as reported by the Radiation Effects Research Foundation. In that report, dosimetry was based on initial radiation only, with the effect of indirect radiation dose not taken into consideration. The atomic bomb radiation, however, consisted of both initial and residual radiation. We reevaluated the dose-response relationship for HD mortality using exposure distance (ground distance between the location where exposed and the hypocenter) as a surrogate indicator of radiation dose. At Hiroshima University, a cohort study has been conducted with Hiroshima Atomic Bomb Survivors (ABS) since 1970. We selected 29605 subjects from the ABS who were exposed at 3.5 km or less from the hypocenter and alive on January 1, 1970. These subjects, referred to as "Hiroshima hibakusha" in this paper, were followed until December 31, 2010. We stratified the cohort data with respect to sex and age at the time of bombing (ATB) into 10-year age groups. For each stratum, by applying an extended Cox regression model with time-dependent covariates, we analyzed the risk of HD mortality using either initial radiation dose or exposure distance as an explanatory variable. The results indicate a high excess risk in males and older age ATB females who were exposed near the hypocenter. This difference may be explained by the effect of female sex hormone on the circulatory system among young age ATB females. Some unknown risk factor related to exposure distance was also implicated in the elevated risk of HD among the Hiroshima hibakusha, especially in males. This necessitates further study.

Background and purpose Mitochondrial dysfunction has been implicated in the pathogenesis of several neurodegenerative disorders, including Machado-Joseph disease (MJD), an autosomal dominant late-onset polyglutamine ataxia that results from an unstable expansion of a CAG tract in the ATXN3 gene. The size of the CAG tract only partially explains age at onset (AO), highlighting the existence of disease modifiers. Mitochondrial DNA (mtDNA) haplogroups have been associated with clinical presentation in other polyglutamine disorders, constituting potential modifiers of MJD phenotype. Methods A cross-sectional study, using 235 unrelated patients from Portugal, Brazil, India and Japan, was performed to investigate if mtDNA haplogroups contribute to AO of MJD. mtDNA haplogroups were obtained after sequencing the mtDNA hypervariable region I. Patients were classified in 15 phylogenetically related haplogroup clusters. Results The AO was significantly different among populations, implying the existence of other non-CAG factors, which seem to be population specific. In the Portuguese population, patients classified as belonging to haplogroup JT presented the earliest onset (estimated onset 34.6 years of age). Haplogroups W and X seem to have a protective effect, causing a delay in onset (estimated onset 47 years of age). No significant association between haplogroup clusters and AO was detected in the other populations or when all patients were pooled. Although haplogroup JT has already been implicated in other neurodegenerative disorders, no previous reports of an association between haplogroups W and X and disease were found. Conclusions These findings suggest that haplogroups JT, W and X modify AO in MJD. Replication studies should be performed in European populations, where the frequency of the candidate modifiers is similar.

SummaryDuring cerebellar development, the main portion of the cerebellar plate neuroepithelium gives birth to Purkinje cells and interneurons, whereas the rhombic lip, the germinal zone at its dorsal edge, generates granule cells and cerebellar nuclei neurons. However, it remains elusive how these components cooperate to form the intricate cerebellar structure. Here, we found that a polarized cerebellar structure self-organizes in 3D human embryonic stem cell (ESC) culture. The self-organized neuroepithelium differentiates into electrophysiologically functional Purkinje cells. The addition of fibroblast growth factor 19 (FGF19) promotes spontaneous generation of dorsoventrally polarized neural-tube-like structures at the level of the cerebellum. Furthermore, addition of SDF1 and FGF19 promotes the generation of a continuous cerebellar plate neuroepithelium with rhombic-lip-like structure at one end and a three-layer cytoarchitecture similar to the embryonic cerebellum. Thus, human-ESC-derived cerebellar progenitors exhibit substantial self-organizing potential for generating a polarized structure reminiscent of the early human cerebellum at the first trimester.

Optineurin (OPTN) is a causative gene in familial amyotrophic lateral sclerosis (ALS) with transactivation response element DNA-binding protein of 43 kDa (TDP-43) protein pathology. Here, we report multiple proteinopathies in familial ALS cases with OPTN mutations. We examined the TDP-43, tau, and α-synuclein pathology of ALS cases with OPTN mutations including 2 previously reported cases (Cases 1 and 2) and 1 newly autopsied case (Case 3) that was clinically diagnosed as ALS and Parkinson disease with a heterozygous E478G OPTN mutation. Pathologic examination of Case 3 showed motor neuron degeneration and depigmentation of the substantia nigra. Neurofibrillary tangles (NFTs) were seen in the hippocampus, pontine tegmentum, and spinal cord. Accumulation of multiple proteins including phosphorylated TDP-43-positive neuronal cytoplasmic inclusions, phosphorylated tau (AT8)-positive NFTs, and α-synuclein-positive Lewy bodies were observed in the substantia nigra. The other 2 cases had a similar distribution of tau pathology, but lacked synuclein pathology. Consecutive sections of Case 3 revealed pTDP-43, AT8, and α-synuclein-positive inclusions in the same neuron and double immunofluorescence staining showed aggregation of different proteins (tau and α-synuclein, or tau and TDP-43) in the same neuron. Our results support the notion that OPTN mutations may lead to multiple proteins aggregation and neuronal degeneration.