The TRK-fused gene is mutated in hereditary motor and sensory neuropathy with proximal dominant involvement.

Hereditary motor and sensory neuropathy with proximal dominant involvement (HMSN-P) is an autosomal-dominant neurodegenerative disorder characterized by widespread fasciculations, proximal-predominant muscle weakness, and atrophy followed by distal sensory involvement. To date, large families affected by HMSN-P have been reported from two different regions in Japan. Linkage and haplotype analyses of two previously reported families and two new families with the use of high-density SNP arrays further defined the minimum candidate region of 3.3 Mb in chromosomal region 3q12. Exome sequencing showed an identical c.854C>T (p.Pro285Leu) mutation in the TRK-fused gene (TFG) in the four families. Detailed haplotype analysis suggested two independent origins of the mutation. Pathological studies of an autopsied patient revealed TFG- and ubiquitin-immunopositive cytoplasmic inclusions in the spinal and cortical motor neurons. Fragmentation of the Golgi apparatus, a frequent finding in amyotrophic lateral sclerosis, was also observed in the motor neurons with inclusion bodies. Moreover, TAR DNA-binding protein 43 kDa (TDP-43)-positive cytoplasmic inclusions were also demonstrated. In cultured cells expressing mutant TFG, cytoplasmic aggregation of TDP-43 was demonstrated. These findings indicate that formation of TFG-containing cytoplasmic inclusions and concomitant mislocalization of TDP-43 underlie motor neuron degeneration in HMSN-P. Pathological overlap of proteinopathies involving TFG and TDP-43 highlights a new pathway leading to motor neuron degeneration.

Defects in the striatal neuropeptide Y system in X-linked dystonia-parkinsonism.

Neuropeptide Y is a novel bioactive substance that plays a role in the modulation of neurogenesis and neurotransmitter release, and thereby exerts a protective influence against neurodegeneration. Using a sensitive immunohistochemical method with a tyramide signal amplification protocol, we performed a post-mortem analysis to determine the striatal localization profile of neuropeptide Y in neurologically normal individuals and in patients with X-linked dystonia-parkinsonism, a major representative of the neurodegenerative diseases that primarily involve the striatum. All of the patients examined were genetically verified as having X-linked dystonia-parkinsonism. In normal individuals, we found a scattered distribution of neuropeptide Y-positive neurons and numerous nerve fibres labelled for neuropeptide Y in the striatum. Of particular interest was a differential localization of neuropeptide Y immunoreactivity in the striatal compartments, with a heightened density of neuropeptide Y labelling in the matrix compartment relative to the striosomes. In patients with X-linked dystonia-parkinsonism, we found a significant decrease in the number of neuropeptide Y-positive cells accompanied by a marked loss of their nerve fibres in the caudate nucleus and putamen. The patients with X-linked dystonia-parkinsonism also showed a lack of neuropeptide Y labelling in the subventricular zone, where a marked loss of progenitor cells that express proliferating cell nuclear antigen was found. Our results indicate a neostriatal defect of the neuropeptide Y system in patients with X-linked dystonia-parkinsonism, suggesting its possible implication in the mechanism by which a progressive loss of striatal neurons occurs in X-linked dystonia-parkinsonism.

Deep brain stimulation of the thalamic ventral lateral anterior nucleus for DYT6 dystonia.

BACKGROUND: A missense mutation of the THAP1 gene results in DYT6 primary dystonia. While deep brain stimulation (DBS) of the internal globus pallidus (GPi) is effective in treating primary dystonia, recent reports indicate that GPi DBS is only mildly effective for DYT6 dystonia. OBJECTIVE: To describe a patient with DYT6 dystonia who underwent thalamic ventral lateral anterior (VLa) nucleus DBS. PATIENT: A 35-year-old Japanese man had been experiencing upper limb dystonia and spasmodic dysphonia since the age of 15. His dystonic symptoms progressed to generalized dystonia. He was diagnosed as having DYT6 dystonia with mutations in the THAP1 gene. Because his dystonic symptoms were refractory to pharmacotherapy and pallidal DBS, he underwent thalamic VLa DBS. RESULTS: Continuous bilateral VLa stimulation with optimal parameter settings ameliorated the patient's dystonic symptoms. At the 2-year follow-up, his Burke-Fahn-Marsden Dystonia Rating Scale total score decreased from 71 to 11, an improvement of more than 80%. CONCLUSIONS: The thalamic VLa nucleus could serve as an alternative target in DBS therapy for DYT6 dystonia.

Therapeutic Effects of Dual Dopaminergic Modulation With l-DOPA and Chlorpromazine in Patients With Idiopathic Cervical Dystonia.

Objectives: Imbalanced activities between dopamine D1 and D2 signals in striatal striosome-matrix system have been proposed as a cause of dystonia symptoms. The aim of this study was to assess the therapeutic effects of dual dopaminergic modulation (DDM) with l-DOPA and chlorpromazine (CPZ) in patients with idiopathic cervical dystonia (CD). Methods: We enrolled 21 patients with CD who responded poorly to botulinum toxin treatment. The severities of CD motor symptoms and CD-associated pain were determined using the Toronto Western Spasmodic Torticollis Rating Scale and the visual analog scale, respectively. Results: In patients with CD (n = 7), oral administration of l-DOPA combined with CPZ significantly attenuated both CD motor symptoms and CD-associated pain in a dose-related manner. By contrast, there was no improvement of CD symptoms in patients (n = 7) who ingested l-DOPA alone nor in those (n = 7) who ingested CPZ alone. Discussion: DDM with l-DOPA and CPZ may be an effective tool to treat dystonia symptoms in patients with botulinum toxin-resistant idiopathic CD. Our results may also indicate that CD dystonia symptoms could be attenuated through DDM inducing an increase in striosomal D1-signaling. Classification of Evidence: This study provides Class III evidence that treatment of botulinum toxin-resistant idiopathic cervical dystonia with l-DOPA and chlorpromazine is superior to either one alone.

Nuclear factor κ B expression in patients with sporadic amyotrophic lateral sclerosis and hereditary amyotrophic lateral sclerosis with optineurin mutations.

Nuclear factor κ B (NF-κB) is involved in the pathogenesis of a number of neurodegenerative disorders with neuroinflammation. In order to clarify the role of NF-κB in ALS, immunohistochemical studies with an antibody that recognizes the p65 subunit of NF-κB were performed on the spinal anterior horn of 4 patients with sporadic ALS (sALS), 1 patient with optineurin-mutated ALS (OPTN-ALS), and 3 normal controls (NC). In patients with sALS or OPTN-ALS, the expression pattern of NF-κB was altered when compared to that of NC; NF-κB immunoreactivity tended to be absent from neuronal nucleus and was increased in microglia. The down-regulation of NF-κB in neuronal nucleus might contribute to a loss of neuroprotection, or neurons with nuclear NF-κB might be lost immediately after its activation. The microglial induction of NF-κB might contribute to neuroinflammation. In conclusion, NF-κB signaling pathway could have a key role in the pathomechanism of ALS.

Truncal dystonia with isolated middle cerebral artery ischemia: A case report of revascularization therapy for dystonia.

Background: Dystonia is a rare movement disorder with some cases being difficult to treat. Although dystonia can occur as a symptom of moyamoya disease, few studies have reported truncal dystonia occurring with middle cerebral artery (MCA) stenosis. Here, we report a case of truncal dystonia with MCA occlusion. Case Description: The patient was a 48-year-old female clerical worker who lived alone. An abnormal cervical posture initially appeared 7 years before (right flexion). Symptoms improved with medication and botulinum toxin injection. Five years before this report, her symptoms worsened, so the dose of oral medication was increased and botulinum treatment was performed, but the symptoms did not improve. The patient showed decreased cerebral blood flow (CBF) in the cortical areas but not in the basal ganglia. We performed superficial temporal artery-MCA bypass surgery because we believed that the dystonia was due to right MCA stenosis. The patient's symptoms improved immediately after surgery, except for her mild cervical backbend. Seven months after the surgery, the patient's involuntary movements showed further improvement, and symptoms have not worsened even after 2 years. Conclusion: Revascularization therapy improved CBF and truncal dystonia and could be a viable treatment option for dystonia with ischemia in the MCA region. Extensive cerebral ischemia can result in cortical inhibition loss or over-adapted cerebral plasticity and cause dystonia. Revascularization therapy may be useful for patients with dystonia and decreased CBF in the MCA region.

Usefulness of the convexity apparent hyperperfusion sign in 123I-iodoamphetamine brain perfusion SPECT for the diagnosis of idiopathic normal pressure hydrocephalus.

OBJECTIVE: The gold standard for the diagnosis of idiopathic normal pressure hydrocephalus (iNPH) is the CSF removal test. For elderly patients, however, a less invasive diagnostic method is required. On MRI, high-convexity tightness was reported to be an important finding for the diagnosis of iNPH. On SPECT, patients with iNPH often show hyperperfusion of the high-convexity area. The authors tested 2 hypotheses regarding the SPECT finding: 1) it is relative hyperperfusion reflecting the increased gray matter density of the convexity, and 2) it is useful for the diagnosis of iNPH. The authors termed the SPECT finding the convexity apparent hyperperfusion (CAPPAH) sign. METHODS: Two clinical studies were conducted. In study 1, SPECT was performed for 20 patients suspected of having iNPH, and regional cerebral blood flow (rCBF) of the high-convexity area was examined using quantitative analysis. Clinical differences between patients with the CAPPAH sign (CAP) and those without it (NCAP) were also compared. In study 2, the CAPPAH sign was retrospectively assessed in 30 patients with iNPH and 19 healthy controls using SPECT images and 3D stereotactic surface projection. RESULTS: In study 1, rCBF of the high-convexity area of the CAP group was calculated as 35.2­43.7 ml/min/100 g, which is not higher than normal values of rCBF determined by SPECT. The NCAP group showed lower cognitive function and weaker responses to the removal of CSF than the CAP group. In study 2, the CAPPAH sign was positive only in patients with iNPH (24/30) and not in controls (sensitivity 80%, specificity 100%). The coincidence rate between tight high convexity on MRI and the CAPPAH sign was very high (28/30). CONCLUSIONS: Patients with iNPH showed hyperperfusion of the high-convexity area on SPECT; however, the presence of the CAPPAH sign did not indicate real hyperperfusion of rCBF in the high-convexity area. The authors speculated that patients with iNPH without the CAPPAH sign, despite showing tight high convexity on MRI, might have comorbidities such as Alzheimer's disease.

Phenotype variability and allelic heterogeneity in KMT2B-Associated disease.

BACKGROUND: Mutations in Lysine-Specific Histone Methyltransferase 2B gene (KMT2B) have been reported to be associated with complex early-onset dystonia. Almost all reported KMT2B mutations occurred de novo in the paternal germline or in the early development of the patient. We describe clinico-genetic features on four Japanese patients with novel de novo mutations and demonstrate the phenotypic spectrum of KMT2B mutations. METHODS: We performed genetic studies, including trio-based whole exome sequencing (WES), in a cohort of Japanese patients with a seemingly sporadic early-onset generalized combined dystonia. Potential effects by the identified nucleotide variations were evaluated biologically. Genotype-phenotype correlations were also investigated. RESULTS: Four patients had de novo heterozygous mutations in KMT2B, c.309delG, c.1656dupC, c.3325_3326insC, and c.5636delG. Biological analysis of KMT2B mRNA levels showed a reduced expression of mutant transcript frame. All patients presented with motor milestone delay, microcephaly, mild psychomotor impairment, childhood-onset generalized dystonia and superimposed choreoathetosis or myoclonus. One patient cannot stand due to axial hypotonia associated with cerebellar dysfunction. Three patients had bilateral globus pallidal deep brain stimulation (DBS) with excellent or partial response. CONCLUSIONS: We further demonstrate the allelic heterogeneity and phenotypic variations of KMT2B-associated disease. Haploinsufficiency is one of molecular pathomechanisms underlying the disease. Cardinal clinical features include combined dystonia accompanying mild psychomotor disability. Cerebellum would be affected in KMT2B-associated disease.

Evaluation of the Edrophonium Challenge Test for Cervical Dystonia.

Objective To examine whether or not an edrophonium challenge test is useful for diagnosing cervical dystonia. Patients We evaluated 10 patients with cervical dystonia and 10 with hemifacial spasms (disease controls). We administered edrophonium and saline in this double-blinded study. Before and after the injection, we recorded the participants' clinical signs using a video camera to assess the objective symptoms every two minutes. Ten minutes after the saline and edrophonium injections, participants evaluated their subjective clinical signs using a visual analog scale. The objective signs on the video recordings were scored by specialists who were blinded to the treatment. The mean visual analog scale scores were compared using the Wilcoxon rank-sum test for paired continuous variables. Results The clinical signs of participants with cervical dystonia were amplified by edrophonium. In contrast, the clinical signs in participants with hemifacial spasms were not affected by the edrophonium challenge test. Conclusion The edrophonium challenge test may be useful for diagnosing cervical dystonia.

Edrophonium Challenge Test for Blepharospasm.

BACKGROUND: Blepharospasm is typically diagnosed by excluding any secondary diseases and neuropsychiatric disorders, as specific tests for blepharospasm are currently unavailable. Since anticholinergic agents are used to improve the symptoms of dystonia, we hypothesized that edrophonium chloride, an acetylcholinesterase inhibitor, may make the symptoms of dystonia more apparent. Therefore, we examined whether an edrophonium challenge test would be useful for diagnosing blepharospasm. METHODS: We studied 10 patients with blepharospasm and 10 with hemifacial spasms (as disease controls). We administered edrophonium and saline in this double-blind study. Before and after the injection, we recorded the clinical signs using a video camera to assess the objective symptoms every 2 min. Ten minutes after the isotonic sodium chloride and edrophonium injections, the patients evaluated their subjective signs using a visual analog scale (VAS). The objective signs on the video recordings were scored by specialists who were blind to the treatment. RESULTS: The subjective and objective signs of the patients with blepharospasm were amplified by edrophonium. In contrast, the signs in patients with hemifacial spasms were not changed by the edrophonium challenge test. CONCLUSIONS: The edrophonium challenge test may be used to diagnose blepharospasm. The study was registered with a ICMJE recognized registry, the UMIN-CTR, with the number UMIN000022557.

[Evaluation of pre-operative administration of TS-1 in patients with advanced gastric or colorectal cancer--estimation of pathological effectiveness for postoperative adjuvant chemotherapy with TS-1].

We performed surgical resections in 6 cases of advanced gastric cancer and 4 cases of colorectal cancer after preoperatively treating them with TS-1 at a daily dose of 80-100 mg/body for 2 weeks, and evaluated whether one can estimate their sensitivity to TS-1 by a pathological examination. Case 1 of type 3 advanced gastric cancer underwent surgery after one week interval following oral administration of TS-1 at a daily dose of 80 mg/body for 2 weeks. Surprisingly, the pathological examination revealed complete disappearance of cancer cells in the resected stomach and no cancer cells in the regional lymphnodes, judged grade 3 in pathological effectiveness. Case 2 of type 2 advanced gastric cancer was treated with TS-1 at a daily dose of 100 mg/body for 2 weeks and underwent surgery after a three-week interval due to the complication of pneumonia. The pathological effectiveness was judged grade 2 in the resected stomach, and no cancer cells were detected in the regional lymphnodes. In both cases, the postoperative course was uneventful, and no adverse effects were detected. In these cases, their high sensitivity to TS-1 was clearly confirmed, and now they have been treated with TS-1 for the postoperative adjuvant chemotherapy, and have undergone regular check-ups at our outpatient clinic in good condition. Recently, we performed the same protocol in 6 cases of advanced gastric cancer including these 2 cases and also in 4 cases of advanced colorectal cancer. This protocol was found useful for evaluating the pathological effect by TS-1. We consider the protocol quite useful and helpful in determining a suitable regimen for postoperative adjuvant chemotherapy.

Spinal Central Effects of Peripherally Applied Botulinum Neurotoxin A in Comparison between Its Subtypes A1 and A2.

Because of its unique ability to exert long-lasting synaptic transmission blockade, botulinum neurotoxin A (BoNT/A) is used to treat a wide variety of disorders involving peripheral nerve terminal hyperexcitability. However, it has been a matter of debate whether this toxin has central or peripheral sites of action. We employed a rat model in which BoNT/A1 or BoNT/A2 was unilaterally injected into the gastrocnemius muscle. On time-course measurements of compound muscle action potential (CMAP) amplitudes after injection of BoNT/A1 or BoNT/A2 at doses ranging from 1.7 to 13.6 U, CMAP amplitude for the ipsilateral hind leg was markedly decreased on the first day, and this muscle flaccidity persisted up to the 14th day. Of note, both BoNT/A1 and BoNT/A2 administrations also resulted in decreased CMAP amplitudes for the contralateral leg in a dose-dependent manner ranging from 1.7 to 13.6 U, and this muscle flaccidity increased until the fourth day and then slowly recovered. Immunohistochemical results revealed that BoNT/A-cleaved synaptosomal-associated protein of 25 kDa (SNAP-25) appeared in the bilateral ventral and dorsal horns 4 days after injection of BoNT/A1 (10 U) or BoNT/A2 (10 U), although there seemed to be a wider spread of BoNT/A-cleaved SNAP-25 associated with BoNT/A1 than BoNT/A2 in the contralateral spinal cord. This suggests that the catalytically active BoNT/A1 and BoNT/A2 were axonally transported via peripheral motor and sensory nerves to the spinal cord, where they spread through a transcytosis (cell-to-cell trafficking) mechanism. Our results provide evidence for the central effects of intramuscularly administered BoNT/A1 and BoNT/A2 in the spinal cord, and a new insight into the clinical effects of peripheral BoNT/A applications.

Response of striosomal opioid signaling to dopamine depletion in 6-hydroxydopamine-lesioned rat model of Parkinson's disease: a potential compensatory role.

The opioid peptide receptors consist of three major subclasses, namely, µ, δ, and κ (MOR, DOR, and KOR, respectively). They are involved in the regulation of striatal dopamine functions, and increased opioid transmissions are thought to play a compensatory role in altered functions of the basal ganglia in Parkinson's disease (PD). In this study, we used an immunohistochemistry with tyramide signal amplification (TSA) protocols to determine the distributional patterns of opioid receptors in the striosome-matrix systems of the rat striatum. As a most striking feature of striatal opioid anatomy, MORs are highly enriched in the striosomes and subcallosal streak. We also found that DORs are localized in a mosaic pattern in the dorsal striatum (caudate-putamen), with heightened labeling for DOR in the striosomes relative to the matrix compartment. In the 6-hydroxydopamine-lesioned rat model of PD, lesions of the nigrostriatal pathways caused a significant reduction of striatal labeling for both the MOR and DOR in the striosomes, but not in the matrix compartment. Our results suggest that the activities of the striosome and matrix compartments are differentially regulated by the opioid signals involving the MORs and DORs, and that the striosomes may be more responsive to opioid peptides (e.g., enkephalin) than the matrix compartment. Based on a model in which the striosome compartment regulates the striatal activity, we propose a potent compensatory role of striosomal opioid signaling under the conditions of the striatal dopamine depletion that occurs in PD.

Dopamine signaling negatively regulates striatal phosphorylation of Cdk5 at tyrosine 15 in mice.

Striatal functions depend on the activity balance between the dopamine and glutamate neurotransmissions. Glutamate inputs activate cyclin-dependent kinase 5 (Cdk5), which inhibits postsynaptic dopamine signaling by phosphorylating DARPP-32 (dopamine- and cAMP-regulated phosphoprotein, 32 kDa) at Thr75 in the striatum. c-Abelson tyrosine kinase (c-Abl) is known to phosphorylate Cdk5 at Tyr15 (Tyr15-Cdk5) and thereby facilitates the Cdk5 activity. We here report that Cdk5 with Tyr15 phosphorylation (Cdk5-pTyr15) is enriched in the mouse striatum, where dopaminergic stimulation inhibited phosphorylation of Tyr15-Cdk5 by acting through the D2 class dopamine receptors. Moreover, in the 1-methyl-4-phenyl-1,2,4,6-tetrahydropyridine (MPTP) mouse model, dopamine deficiency caused increased phosphorylation of both Tyr15-Cdk5 and Thr75-DARPP-32 in the striatum, which could be attenuated by administration of L-3,4-dihydroxyphenylalanine and imatinib (STI-571), a selective c-Abl inhibitor. Our results suggest a functional link of Cdk5-pTyr15 with postsynaptic dopamine and glutamate signals through the c-Abl kinase activity in the striatum.

[Dystonia genes and elucidation of their roles in dystonia pathogenesis].

Identification of causative genes for hereditary dystonia and elucidation of their functions are crucial for better understanding of dystonia pathogenesis. As seen in other hereditary neurologic disorders, intra- and inter-familial clinical variations have been demonstrated in hereditary dystonia. Asymptomatic carriers can be found due to alterations in penetrance, generally reduced in succeeding generations. Current known dystonia genes include those related to dopamine metabolism, transcription factor, cytoskeleton, transport of glucose and sodium ion, etc. It has been reported that effects of deep brain stimulation can vary significantly depending on genotype. Accumulation of genotype-outcome correlations would contribute to treatment decisions for dystonia patients.

[New medications for dystonia].

Although there are some newly-developed options to treat dystonia, its medical treatment is not always satisfactory. Zolpidem, an imidazopyridine agonist with a high affinity to benzodiazepine receptor subtype ω1, has been reported to improve clinical symptoms of dystonia in some cases. We conducted an open-label study to assess the efficacy of zolpidem in 34 patients with primary dystonia patients, The Burke Fahn Marsden Dystonia Rating Scale (BFMDRS) scores in the patients were decreased from 7.2 ± 7.9 to 5.5 ± 5.0 after zolpidem therapy (P=0.042). Next we evaluated 55 patients with primary and secondary dystonia, 16 of 55 patients (29%) responded to zolpidem, and secondary dystonia, particularly post-traumatic dystonia, was more responsive than primary dystonia (5 of 11 [46%] vs 11 of 44 [25%]). The efficacy of zolpidem was comparable to that of other oral medications in our previous study; 33 of 89 dystonia patients (37%) responded to trihexyphenidil, 13 of 53 (25%) responded to clonazepam, and 4 of 21 (19%) responded to baclofen. In conclusion, our large scale study suggested that zolpidem may be a therapeutic option for dystonia, particularly post-traumatic dystonia.

Antibodies to N-methyl-D-aspartate glutamate receptors in Creutzfeldt-Jakob disease patients.

Psychiatric symptom can be a prominent feature early in Creutzfeldt-Jakob disease (CJD), which is also common in autoantibody-mediated limbic encephalitis. We hypothesized that anti-neuronal autoantibodies, especially those against N-methyl-D-aspartate glutamate receptors (NMDAR), can also be associated with CJD. Thirteen patients with CJD and 13 patients with limbic encephalitis were enrolled. Immunohistochemistry demonstrated that serum of CJD patients reacted with neuronal components of the rat hippocampus, indicating that those samples contained anti-neuronal antibodies. Enzyme-linked immunosorbent assay revealed that titers of antibodies against peptides of GluN2B subunit of NMDAR were significantly elevated in the serum and cerebrospinal fluid of CJD patients.