Mitochondrial localization of PABPN1 in oculopharyngeal muscular dystrophy.

Oculopharyngeal muscular dystrophy (OPMD) is a late-onset disorder characterized by ptosis, dysphagia, and weakness of proximal limbs. OPMD is caused by the expansion of polyalanine in poly(A)-binding protein, nuclear 1 (PABPN1). Although mitochondrial abnormality has been proposed as the possible etiology, the molecular pathogenesis is still poorly understood. The aim of the study was to specify the mechanism by which expanded PABPN1 causes mitochondrial dysfunction in OPMD. We evaluated whether transgenic mouse model of OPMD, by expressing expanded PABPN1, indeed causes mitochondrial abnormality associated with muscle degeneration. We also investigated the mechanism by which expanded PABPN1 would cause mitochondrial dysfunction in the mouse and cell models of OPMD. Mitochondrial localization of PABPN1 was observed in the muscle fibers of patients with OPMD. Moreover, abnormal accumulation of PABPN1 on the inner membrane of mitochondria and reduced expression of OXPHOS complexes were detected in the muscle fibers of the transgenic mice expressing expanded human PABPN1 with a 13-alanine stretch. In cells expressing PABPN1 with a 10-alanine or 18-alanine stretch, both types of PABPN1 accumulated in the mitochondria and interacted with TIM23 mitochondrial protein import complex, but PABPN1 with 18-alanine stretch decreased the cell viability and aggresome formation. We proposed that the abnormal accumulation of expanded PABPN1 in mitochondria may be associated with mitochondrial abnormality in OPMD.

Heterozygous mutations of the kinesin KIF21A in congenital fibrosis of the extraocular muscles type 1 (CFEOM1).

Congenital fibrosis of the extraocular muscles type 1 (CFEOM1; OMIM #135700) is an autosomal dominant strabismus disorder associated with defects of the oculomotor nerve. We show that individuals with CFEOM1 harbor heterozygous missense mutations in a kinesin motor protein encoded by KIF21A. We identified six different mutations in 44 of 45 probands. The primary mutational hotspots are in the stalk domain, highlighting an important new role for KIF21A and its stalk in the formation of the oculomotor axis.

Deep venous thrombosis in patients with neurological diseases: A multicenter, prospective study.

OBJECTIVE: Patients with neurological diseases are liable to develop deep venous thrombosis (DVT) due to various factors. We investigated the prevalence, related factors, and prognosis of DVT in patients with neurological diseases. METHODS: Patients admitted to four hospitals due to neurological diseases were prospectively recruited. Those with cerebrovascular diseases were excluded. To screen for DVT, ultrasonography was performed in patients with possible DVT risk, such as D-dimer > 1.0 µg/dL, recent surgery, active malignant diseases, recent bone fracture, decreased activity, or treatment with immunoglobulin or steroid therapy. Clinical characteristics were compared between patients with and without DVT. RESULTS: A total of 106 patients (54 women, median 71 years old) were included. DVT was detected in 27 patients (26.0%) at the first assessment. All had DVT only in the calf; encephalopathy/meningitis (n = 4, 40.0%) had the highest prevalence of DVT among the underlying neurological diseases, followed by parkinsonian syndrome (n = 6, 37.5%). Independent predictors for DVT detection were malignant diseases (odds ratio, 11.7; 95% confidence interval, 1.0-301.4), modified Rankin Scale score ≥ 4 (5.4; 1.9-16.6), and D-dimer ≥ 2.0 µg/dL (5.7; 2.1-16.7). Ten patients were treated with anticoagulants, and no patients developed a symptomatic pulmonary embolism. No clinically evident pulmonary embolisms, systemic embolisms, or severe bleeding complications were observed in patients with DVT. CONCLUSIONS: Asymptomatic DVT is not rare in patients with neurological diseases, especially in those with malignancy, decreased activity, or elevated D-dimer. The overall prognosis is favorable, but the potential risk of development of a pulmonary embolism should be recognized.

Familial Parkinsonism with digenic parkin and PINK1 mutations.

To clarify the genetic correlation between parkin and PINK1, we screened for PINK1 mutations in 175 parkinsonism patients with parkin mutations. We detected two sibling pairs and one sporadic patient carrying both parkin and PINK1 mutations. The age at onset of Parkinsonism of patients with the digenic mutations was lower than that of patients with the same parkin mutation alone. In addition, two of three patients carrying both parkin and PINK1 mutations had schizophrenia. These findings indicate that PINK1 mutation might modify parkin mutation-positive Parkinsonism, and PINK1 mutations might be associated with psychiatric disorders.

[Seizure-induced transient brain edema in the medial temporal lobe].

We reported a patient with sudden onset seizure resulting in prolonged amnesia. MRI revealed a T2 high signal lesion with swelling in the right medial temporal lobe. Because the MRI lesion remained to be the same in size for two months, biopsy specimens were obtained under informed consent to rule out the brain tumor. Based on histological findings showing brain edema without specific abnormal findings (malignancy, inflammation etc), we concluded that the temporal lesion was the edema induced by the seizure attack. In Japan, many papers on non-herpetic acute limbic encephalitis (NHALE) have recently been published. In their reports, seizures were frequently observed as a preceding symptom; moreover, clinical courses and MRI findings are similar to those of seizure-induced brain edema. The secondary brain edema induced by the seizure must be considered in patients with NHALE and other CNS disorders, especially if the patient has a history of the recent seizure.

Two cases of hemiballism-hemichorea with T1-weighted MR image hyperintensities.

Two cases of hemiballism-hemichorea have been reported in woman patients with hyperglycemia; this was a feature of striatal hyperintensity on the T1-weighted MRI. In the first case, strict management of diabetes and treatment with pimozide effectively suppressed the movement disorder. The Z-score Imaging System revealed hyperperfusion in the bilateral dentate nuclei, left striatum, and bilateral motor cortices. In the second case, painful hemiballism-hemichorea limb, followed by the upper limb. The severity of HB-HC corresponded to the expansion of the striatal lesion. The mechanism of HB-HC by using statistical cerebral blood flow evaluation has also been discussed.

Genotypic and phenotypic spectrum of CADASIL in Japan: the experience at a referral center in Kumamoto University from 1997 to 2014.

This study elucidates the genotypic and phenotypic spectrum and histopathological findings related to cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) in Japan. For this single-center retrospective observational study, we enrolled 215 patients who were clinically suspected of having CADASIL and were examined at Kumamoto University from 1997 to 2014, and we diagnosed CADASIL in 70 patients. We found 19 different NOTCH3 mutations in the patients, with the NOTCH3 Arg133Cys mutation being found most frequently. We also found the Arg75Pro mutation, a cysteine-sparing NOTCH3 mutation. CADASIL patients with this Arg75Pro mutation were frequently found throughout Japan, and fewer patients with the Arg75Pro mutation showed MRI hyperintensity in the anterior temporal pole compared with patients with other NOTCH3 mutations. Significantly more CADASIL patients with the NOTCH3 Arg133Cys mutation had hyperintensity in the external capsule compared with CADASIL patients with the other mutations not including the NOTCH3 Arg75Pro mutation. We also showed postmortem pathological findings of the first Japanese CADASIL case with the NOTCH3 Arg133Cys mutation, and histopathological findings of fresh frozen skin biopsy specimens of CADASIL patients. In conclusions, the spectrum of NOTCH3 mutations in Japanese CADASIL patients may be partially explained by founder effects. Genotype-phenotype correlations may exist in CADASIL, which should be considered so as to make an accurate diagnosis of CADASIL in each population. Fresh frozen skin biopsy specimens may aid detection of Notch3 deposits on vascular walls for an improved diagnosis of CADASIL.

Apparent genotype-phenotype correlation in childhood, adolescent, and adult Chediak-Higashi syndrome.

Chediak-Higashi syndrome (CHS) is a rare autosomal recessive disorder characterized by severe immunologic defects, reduced pigmentation, bleeding tendency, and progressive neurological dysfunction. Most patients present in early childhood and die unless treated by bone marrow transplantation. About 10-15% of patients exhibit a much milder clinical phenotype and survive to adulthood, but develop progressive and often fatal neurological dysfunction. Very rare patients exhibit an intermediate adolescent CHS phenotype, presenting with severe infections in early childhood, but a milder course by adolescence, with no accelerated phase. Here, we describe the organization and genomic DNA sequence of the CHS1 gene and mutation analysis of 21 unrelated patients with the childhood, adolescent, and adult forms of CHS. In patients with severe childhood CHS, we found only functionally null mutant CHS1 alleles, whereas in patients with the adolescent and adult forms of CHS we also found missense mutant alleles that likely encode CHS1 polypeptides with partial function. Together, these results suggest an allelic genotype-phenotype relationship among the various clinical forms of CHS.

Pantothenate kinase-associated neurodegeneration initially presenting as postural tremor alone in a Japanese family with homozygous N245S substitutions in the pantothenate kinase gene.

We describe a 24-year-old Japanese woman with pantothenate kinase-associated neurodegeneration (PKAN) whose only early symptom was postural tremor in the right hand at around 18 years of age, leading to a diagnosis of essential tremor at age 21. Although she was treated with arotinolol hydrochloride and clonazepam, she gradually progressed to extrapyramidal and pyramidal signs several years later. T2-weighted magnetic resonance images (MRI) showed bilaterally marked hypointensity with a central region of hyperintensity in the globus pallidus, or the so-called "eye-of-the-tiger" sign. Six years have passed since the initial appearance of postural tremor, whereas she has not shown choreoathetosis, retinitis pigmentosa, optic atrophy, or seizure. Direct sequencing of the patient's genomic DNA revealed homozygous base substitutions in the pantothenate kinase gene (PANK2): the A764-->G substitution (N245S) due to consanguinity of her parents. Although the heterozygous form of this mutation has already been reported among several families, this is the first report of the homozygous mutation in a patient with atypical-type PKAN. This detailed description of the clinical features of a Japanese patient with PKAN arising from homozygous N245S mutations in PANK2 would be useful for elucidating the pathogenesis of PKAN.

Genetic, clinical and pathological studies of CADASIL in Japan: a partial contribution of Notch3 mutations and implications of smooth muscle cell degeneration for the pathogenesis.

We have examined Notch3 mutations in patients with cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) whose samples were submitted to us in Japan. The subjects were composed of 21 Japanese, 1 Iranian, 1 Korean and 1 Canadian families. Mutations in the Notch3 gene were found in 7 of 24 families examined. These were R133C in two unrelated Japanese families, and R213K, C174F and R169C in each Japanese family. In addition, we have found R90C in an Iranian family and C174R in a Korean family. Thus, contribution of Notch3 gene mutations is less than one fourth of Japanese CADASIL families, suggesting the existence of other causative genes in CADASIL. It is also of interest to know that Notch3 mutant CADASIL exists in other Asian countries. We next examined the localization of Notch3 protein in the tissue by immunohistochemistry. It was restricted to the wall of arterioles in the brain and other organs. In the brain, there was no difference in the staining pattern among arterioles in the cortex, white matter and meninges. The staining was negative in the venule and capillaries as well as in neurons and glial cells. From the staining pattern, it was recognized to be expressed in the vascular smooth muscle cells in the adult tissue. In an autopsy case with R213K mutation, we could see numerous cerebral infarcts and arteriole wall degeneration with deposits of granular osmiophilic material (GOM). However, it is interesting to note that occlusion of arterioles was rarely observed and the GOM was negative for Notch3 staining. These findings suggest that hemodynamic abnormalities due to smooth muscle cell degeneration may be important in the pathogenesis of CADASIL.

A unique case of sporadic Creutzfeldt-Jacob disease presenting as progressive supranuclear palsy.

We report a Japanese case of sporadic Creutzfeldt-Jakob disease (CJD) presenting as progressive supranuclear palsy. For 2 years after onset, neurological deficits had slowly progressed but neither myoclonus nor periodic synchronous discharge was observed. Diffusion-weighted image (DWI) showed unique high signal lesions in the bilateral frontal cortex, left parietooccipital and occipital cortices, but there was nearly no change eight months later. Needle biopsy revealed deposition of prion protein of a patchy/perivacuolar type with spongiform degeneration. Thus, the phenotype of sporadic CJD seems variable and DWI should be performed, even in atypical cases lacking the characteristics of CJD.

[A case of slowly progressive aphasia accompanied with auditory agnosia].

A 68-year-old right-handed woman was admitted to our hospital because of difficulty to speak and understand conversation over 10 years. She was able to make herself by writing. No change in her personality or behavioral abnormality was observed so that she could live without help. Although her WAIS score and auditory brain stem response were normal, she could not understand the speech or distinguish the sound. She also spoke plenty of words fluently, resulting in undifferentiated jargon. She did not make any effort in speaking. Her speech was, however, unclear and hard to understand. Brain MRI scan disclosed a moderate atrophy of bilateral temporal lobe and enlargement of Sylvius fissure. A three-dimension reconstructed brain surface image showed enlargement of the perisylvian fissure, and atrophy of the gyrus frontalis inferior, operculum, gyrus temporal superior, bilaterally. Reduced cerebral blood flow was demonstrated on 99mTc-ECD SPECT in the left thalamus and bilateral fronto-temporal lobe. A diagnosis of slowly progressive aphasia with auditory agnosia was made. Our case suggests that bilateral disturbance of neuronal network between the primary auditory area and the secondary auditory area is responsible to the consequence of auditory agnosia.

[A case of spontaneous intracranial hypotension without any history of positional headache].

A 52-year-old woman was admitted to our hospital with sudden diplopia, right ophthalmalgia, and occipital pain. The nature of her headache was continuous, and changing her position provided no relief. Three weeks before her admission, she experienced continuous cough and rhinorrhea during a few days. On admission, her neurological examination revealed right abducens paralysis, and right lateral gaze aggravated diplopia. Brain magnetic resonance imaging scan demonstrated diffuse pachymeningeal enhancement by gadolinium. Radioisotope cisternography showed a leak of cerebrospinal fluid from near the third lumbar vertebra. The first lumbar puncture revealed an initial pressure of 0 mm H2O. She was given a diagnosis of spontaneous intracranial hypotension due to a leak of the cerebrospinal fluid. During her hospitalization, she complained of vertigo and nausea. We found horizontal gaze nystagmus to left side and sensorineural deafness in her left ear, which improved in a few days. After treatment by a lumbar epidural continuous infusion of saline and a lumbar epidural blood patch, her headache and abnormal MRI findings had improved. The continuous cough before her admission may be the cause of the leak of cerebrospinal fluid. We had difficulty in diagnosis only by the history and clinical examination, because she had no history of orthostatic headache.

[Fabry disease in light of recent review].

Fabry disease is a lysosomal storage disorder that is caused by mutations in the gene encoding a-galactosidase A on Xq22.1. Typically hemizygous male patients exhibit classic phenotypes such as angiokeratoma, acroparesthesias, episodic pain "crises," hypohidrosis, and whorl-shaped corneal opacities from childhood. However, during adulthood, they gradually develop kidney failure, heart disease, and strokes resulting in early death between 40 to 50 years of age. However, recent studies have indicated a high prevalence of disabling clinical symptoms in heterozygous females patients. Patients having the cardiac variant of Fabry's disease exhibit only left ventricular hypertrophy, while patients having the renal variant exhibit only kidney failure. Individuals affected by these variants show higher residual enzyme activity of alpha-galactosidase A than individuals affected by the classic form of Fabry's disease due to missense mutations of the GLA gene. The cerebrovascular involvement in Fabry disease is not rare in both adult hemizygotes and heterozygotes. Infarctions caused by the occulsion of small vessels involving mostly the vertebrobasilar region in approximately two-thirds of the cases, and that is associated with the deposition glycoshingolipids including GL-3 in the walls of these vessels. In Caucasian patients, elongated, ectatic, and tortuous vertebral and basilar arteries are frequently observed on MRAs. Life-threatening megadolichobasilar anomaly with thrombosis has been identified in a large Hungarian family in which the family members share L16P mutation. On performing MRI, an increased signal intensity was observed in the pulvinar in T1-weighted images; this is the characteristic so-called "pulvinar sign". Enzyme replacement therapy has been approved in Japan since 2004 and 2007 for agalsidase beta and agalsidase alpha, respectively. This treatment modestly improves the small-fiber neuropathy, hypohidrosis, hypertrophic cardiomyopathy, and stabilizes the renal function in the long term for up to 54 months. However, it has not helped in decreasing the incidence of strokes.

Paraneoplastic limbic encephalitis caused by ovarian teratoma with autoantibodies to glutamate receptor.

We report a rare case of paraneoplastic limbic encephalitis with autoantibodies to glutamate receptor (GluR) in the cerebrospinal fluid (CSF). The 35-year-old woman with consciousness disturbance was diagnosed initially as non-herpetic encephalitis. Her signs and symptoms improved with acyclovir and steroid pulse therapy. However, after the treatment, an ovarian tumor was discovered, and we detected autoantibodies to GluR in the CSF. A possible association between the ovarian teratoma and GluR is suggested.

Neurologic toxicity associated with interferon alpha therapy for renal cell carcinoma.

A 67-year-old man received interferon alpha (IFN alpha) therapy for lung metastases of renal cell carcinoma (RCC). Multiple pulmonary metastases disappeared completely. However, neurological toxicity was detected by magnetic resonance imaging (MRI) as abnormal brain lesions. After discontinuation of IFN alpha therapy, his neurological symptoms and abnormal lesions on MRI disappeared completely. Complete remission of RCC has continued, and results of neurological study have remained normal for 5 years after discontinuation of IFN alpha therapy.

Distal myopathy with rimmed vacuoles: impaired O-glycan formation in muscular glycoproteins.

Distal myopathy with rimmed vacuoles (DMRV), is an autosomal recessive disorder with early adult onset, displays distal dominant muscular involvement and is characterized by the presence of numerous rimmed vacuoles in the affected muscle fibers. The pathophysiology of DMRV has not been clarified yet, although the responsible gene was identified as that encoding UDP-N-acetylglucosamine 2-epimerase/N-acetylmannosamine kinase involved in the biosynthesis of sialic acids. To identify defective carbohydrate moieties of muscular glycoproteins from DMRV patients, frozen skeletal muscle sections from seven patients with DMRV, as well as normal and pathological controls, were treated with or without sialidase or N-glycosidase F followed by lectin staining and lectin blotting analysis. The sialic acid contents of the O-glycans in the skeletal muscle specimens from the DMRV patients were also measured. We found that Arachis hypogaea agglutinin (PNA) lectin reacted strongly with sarcolemmal glycoproteins in the DMRV patients but not with those in control subjects. alpha-Dystroglycan from the DMRV patients strongly associated with PNA lectin, although that from controls did not. The sialic acid level of the O-glycans in the DMRV muscular glycoproteins with molecular weights of 30 to 200 kd was reduced to 60 to 80% of the control level. The results show that impaired sialyl O-glycan formation in muscular glycoproteins, including alpha-dystroglycan, occurs in DMRV.

Effective repetitive dystrophin gene transfer into skeletal muscle of adult mdx mice using a helper-dependent adenovirus vector expressing the coxsackievirus and adenovirus receptor (CAR) and dystrophin.

BACKGROUND: The helper-dependent adenovirus (HDAd) vector is less immunogenic and has a larger cloning capacity of up to 37 kb enough to carry the full-length dystrophin cDNA. However, high and long-term expression of dystrophin transduced to mature muscle still remains difficult. One of the main reasons for this is that the expression of the coxsackievirus and adenovirus receptor (CAR) is very low in mature muscle. METHODS: We have constructed two different HDAd vectors. One contains the LacZ and the murine full-length dystrophin expression cassette (HDAdLacZ-dys), and the other is a new, improved vector containing the CAR and the dystrophin expression cassette (HDAdCAR-dys). RESULTS: We initially demonstrated high dystrophin expression and prevention of the dystrophic pathology in mdx muscle injected during the neonatal phase with HDAdLacZ-dys. Furthermore, we demonstrated that repeated injections of HDAdCAR-dys into mature muscle led to approximately nine times greater dystrophin-positive fibers in number than a single injection, thereby recovering the expression of dystrophin-associated proteins. This data has also shown that HDAdCAR-dys enabled administration of adenovirus (Ad) vector to the host with pre-existing immunity to the same serotype of Ad. CONCLUSIONS: Repetitive injections of the HDAd vector containing the CAR and the dystrophin expression cassette could improve the efficiency of subsequent dystrophin gene transfer to mature mdx muscle. This result suggests that our new HDAd vector will provide a novel gene therapy strategy for Duchenne muscular dystrophy, raising the prospects for gene therapy of other hereditary myopathies.