The clinical and molecular spectrum of ZFYVE26-associated hereditary spastic paraplegia: SPG15.

In the field of hereditary spastic paraplegia (HSP), progress in molecular diagnostics needs to be translated into robust phenotyping studies to understand genetic and phenotypic heterogeneity and to support interventional trials. ZFYVE26-associated hereditary spastic paraplegia (HSP-ZFYVE26, SPG15) is a rare, early-onset complex HSP, characterized by progressive spasticity and a variety of other neurological symptoms. While prior reports, often in populations with high rates of consanguinity, have established a general phenotype, there is a lack of systematic investigations and a limited understanding of age-dependent manifestation of symptoms. Here we delineate the clinical, neuroimaging and molecular features of 44 individuals from 36 families, the largest cohort assembled to date. Median age at last follow-up was 23.8 years covering a wide age range (11-61 years). While symptom onset often occurred in early childhood [median: 24 months, interquartile range (IQR) = 24], a molecular diagnosis was reached at a median age of 18.8 years (IQR = 8), indicating significant diagnostic delay. We demonstrate that most patients present with motor and/or speech delay or learning disabilities. Importantly, these developmental symptoms preceded the onset of motor symptoms by several years. Progressive spasticity in the lower extremities, the hallmark feature of HSP-ZFYVE26, typically presents in adolescence and involves the distal lower limbs before progressing proximally. Spasticity in the upper extremities was seen in 64%. We found a high prevalence of extrapyramidal movement disorders including cerebellar ataxia (64%) and dystonia (11%). Parkinsonism (16%) was present in a subset and showed no sustained response to levodopa. Cognitive decline and neurogenic bladder dysfunction progressed over time in most patients. A systematic analysis of brain MRI features revealed a common diagnostic signature consisting of thinning of the anterior corpus callosum, signal changes of the anterior forceps and non-specific cortical and cerebellar atrophy. The molecular spectrum included 45 distinct variants, distributed across the protein structure without mutational hotspots. Spastic Paraplegia Rating Scale scores, SPATAX Disability Scores and the Four Stage Functional Mobility Score showed moderate strength in representing the proportion of variation between disease duration and motor dysfunction. Plasma neurofilament light chain levels were significantly elevated in all patients (Mann-Whitney U-test, P < 0.0001) and were correlated inversely with age (Spearman's rank correlation coefficient r = -0.65, P = 0.01). In summary, our systematic cross-sectional analysis of HSP-ZFYVE26 patients across a wide age-range, delineates core clinical, neuroimaging and molecular features and identifies markers of disease severity. These results raise awareness to this rare disease, facilitate an early diagnosis and create clinical trial readiness.

A case of monozygotic twins with hereditary spastic paraplegia type 4 and epilepsy, of whom only one developed narcolepsy type 1.

We report a case of monozygotic twin sisters with hereditary spastic paraplegia type 4 (SPG4) and epilepsy, only one of whom had a diagnosis of narcolepsy type 1 (NT1). The older sister with NT1 exhibited excessive daytime sleepiness, cataplexy, sleep-onset rapid eye movement period in the multiple sleep latency test, and decreased orexin levels in cerebrospinal fluid. Both sisters had HLA-DRB1*15:01-DQB1*06:02 and were further identified to have a novel missense mutation (c.1156A > C, p.Asn386His) in the coding exon of the spastin (SPAST) gene. The novel missense mutation might be involved in the development of epilepsy. This case is characterised by a combined diagnosis of SPG4 and epilepsy, and it is the first report of NT1 combined with epilepsy and genetically confirmed SPG4. The fact that only one of the twins has NT1 suggests that acquired and environmental factors are important in the pathogenesis of NT1.

Recurrent embolic stroke associated with adenomyosis: A single case report and literature review.

INTRODUCTION: Uterine adenomyosis is a benign disorder in which endometrial glands and stroma are present within the myometrium. There have been several case reports of cerebral infarction associated with adenomyosis, but their clinical characteristics, optimal treatment, and prognosis have not been systematically reviewed. METHODS: A case of cerebral infarction with adenomyosis is reported, and a comprehensive systematic literature search using the PubMed database was conducted. RESULTS: A 42-year-old woman, previously diagnosed with adenomyosis, developed multiple cerebral infarctions during menstruation. Her CA125 level was 293 U/mL, and treatment with edoxaban 30 mg was started. Seven days after hospital discharge, she had her subsequent menstrual period and then developed a recurrent stroke. Her CA125 level was 743 U/mL on readmission. A hysterectomy was performed, and the patient has had no further stroke recurrence. A systematic review identified 19 cases with cerebral infarction associated with adenomyosis, including the present case. The patients' clinical characteristics included young age (44.7 ± 6.2 years), stroke development during menstruation (85%), multiple infarctions affecting ≥ 3 vessel territories (39%), and high levels of CA125 and D-dimer (810.6 ± 888.4 U/mL, and 10.3 ± 18.6 µg/mL, respectively). Antithrombotic therapy was given to 14 patients, but recurrent stroke occurred in 5 (36%) patients. Hysterectomy was conducted in 5 and 4 patients with initial and recurrent stokes, respectively, and there were no further recurrences thereafter. CONCLUSION: Cerebral infarction associated with adenomyosis has specific clinical characteristics. Antithrombotic therapy was insufficient, and hysterectomy should particularly be considered in cases of recurrent stroke.

A clinical and genetic study of SPG31 in Japan.

SPG31 is an autosomal dominant hereditary spastic paraplegia caused by pathogenic variants in the receptor expression-enhancing protein 1 (REEP1) gene. We analyzed 488 DNA samples from unrelated HSP patients collected by Japan Spastic Paraplegia Research Consortium and found 15 Japanese SPG31 families. We investigated each family and found a total of 25 individuals with REEP1 variants (comprising 22 patients and three asymptomatic carriers). Fourteen REEP1 variants (five missense, three nonsense, four frameshift, one splice site, and one large deletion) including 11 novel ones were detected. Seventy percent of the patients (14 of 20) showed a pure form and the others (6 of 20) showed a complicated form with peripheral neuropathy. Fifty percent of the patients had neurological symptoms before the age of 10 and 20% of them at age 41-50. The mean age of onset was 19.6 ± 18.7 (from 5 to 67, n = 15) years for males and 32.8 ± 24.7 (from 4 to 60, n = 5) years for females. Although the difference was not statistically significant (p = 0.38, Mann-Whitney U test), males tended to have an earlier age of onset. Moreover, all three asymptomatic carriers were female. We investigated additional factors as to phenotypic appearance in one family with apparent intrafamilial variability in age at onset and clinical severity, but no additional factors including gene variants could be found. This is the first report of clinical and genetic findings of SPG31 in Japan, which may lead to further studies of the genotype-phenotype correlation of SPG31.

Chédiak-Higashi syndrome presenting as a hereditary spastic paraplegia.

Hereditary spastic paraplegias (HSPs) comprise a group of neurodegenerative disorders characterized by weakness and leg spasticity. LYST is responsible for Chédiak-Higashi syndrome (CHS), which exhibits partial oculocutaneous albinism, primary immunodeficiency, and bleeding tendency in childhood. Although neurological symptoms of CHS also appear in adulthood, a phenotype of spastic paraplegia has rarely been reported in CHS. In this study, we investigated LYST mutations in 387 HSP patients through the Japan Spastic Paraplegia Research Consortium to clarify the frequency of LYST mutations in HSP, finding six adult patients with LYST mutations in four HSP families. They exhibited intellectual disability, cerebellar ataxia, neuropathy, and pyramidal signs. Meanwhile, only 15 patients with CHS in childhood have been revealed in a decade by a nationwide survey in Japan. Thus, LYST mutations might indicate a HSP phenotype in a considerable number of adult patients with CHS.

Ubap1 knock-in mice reproduced the phenotype of SPG80.

SPG80 is a neurodegenerative disorder characterized by a pure type of juvenile-onset hereditary spastic paraplegia and is caused by a heterozygous mutation of the UBAP1 (ubiquitin-associated protein 1) gene. UBAP1 is one of the subunits of the endosomal sorting complex required for transport I and plays a role in endosome sorting by binding to ubiquitin-tagged proteins. In this study, we generated novel Ubap1+/E176Efx23 knock-in mice, in which the SOUBA domain of Ubap1 was completely deleted with the UMA domain being intact, as an animal model of SPG80. The knock-in mice with this heterozygous Ubap1 truncated mutation appeared normal at birth, but they developed progressive hind limb dysfunction several months later. Molecular pathologically, loss of neurons in the spinal cord and accumulation of ubiquitinated proteins were observed in Ubap1+/E176Efx23 knock-in mice. In addition, changes in the distributions of Rab5 and Rab7 in the spinal cord suggest that this mutation in Ubap1 disturbs endosome-mediated vesicular trafficking. This is the first report of a mouse model that reproduces the phenotype of SPG80. Our knock-in mice may provide a clue for understanding the molecular pathogenesis underlying UBAP1-related HSP and screening of therapeutic agents.

[Other Central Nervous System Infections(Including Fungal Infection, Tuberculosis, and Parasitic Infection)].

This review describes cryptococcal meningoencephalitis, tuberculous meningitis, neurosyphilis, and toxoplasma encephalitis. Central nervous system infections are neurological emergencies associated with mortality or other outcomes. Therefore, early diagnosis and treatment are critical. Fungal or gondii infections are rare and affect compromised hosts who are HIV positive, have diabetes, or take immunosuppressive or anticancer drugs. Cryptococcal antigens in the serum and cerebrospinal fluid are useful for the diagnosis of cryptococcal meningoencephalitis. RPR and TPHA tests are useful for the diagnosis of neurosyphilis. Cryptococcal meningoencephalitis and tuberculous meningitis often develop into hydrocephalus, making VP shunt necessary. Antifungal drugs for cryptococcal meningitis are limited by the blood-brain barrier, making a full recovery difficult; in such situations, intraventricular antifungal treatment is required.

A Nepalese family with an REEP2 mutation: clinical and genetic study.

Hereditary spastic paraplegias (HSPs) are clinically and genetically heterogeneous neurodegenerative disorders characterized by progressive weakness and spasticity in the lower limbs due to pyramidal tract dysfunction. REEP2 mutations have been identified as a cause of "pure" HSP, SPG72, with both autosomal dominant and autosomal recessive inheritance. We describe a rare Nepalese family with early-onset pure-type HSP harboring a heterozygous REEP2 missense mutation (c.119T>G, p.Met40Arg). This is only the second SPG72 family with autosomal dominant inheritance. The proband presented slow and spastic gait at age 2 years and the symptoms progressed slowly. The proband's father and uncle presented even milder symptoms of pure spastic paraplegia. Our study may provide an opportunity to further study the genotype-phenotype correlation of SPG72.

A p.Arg499His mutation in SPAST is associated with infantile-onset complicated spastic paraplegia: a case report and review of the literature.

BACKGROUND: Spastic paraplegia type 4 (SPG4) is caused by mutations in the SPAST gene, is the most common form of autosomal-dominant pure hereditary spastic paraplegias (HSP), and is rarely associated with a complicated form that includes ataxia, epilepsy, and cognitive decline. To date, the genotype-phenotype correlation has not been substantially established for SPAST mutations. CASE PRESENTATION: We present a Japanese patient with infantile-onset HSP and a complex form with coexisting ataxia and epilepsy. The sequencing of SPAST revealed a de novo c.1496G > A (p.R499H) mutation. A review of the literature revealed 16 additional patients with p.R499H mutations in SPAST associated with an early-onset complicated form of HSP. We found that the complicated phenotype of patients with p.Arg499His mutations could be mainly divided into three subgroups: (1) infantile-onset ascending hereditary spastic paralysis, (2) HSP with severe dystonia, and (3) HSP with cognitive impairment. Moreover, the c.1496G > A mutation in SPAST may occur as a de novo variant at noticeably high rates. CONCLUSION: We reviewed the clinical features of the patients reported in the literature with the p.Arg499His mutation in SPAST and described the case of a Japanese patient with this mutation presenting a new complicated form. Accumulating evidence suggests a possible association between infantile-onset complicated HSP and the p.Arg499His mutation in SPAST. The findings of this study may expand the clinical spectrum of the p.Arg499His mutation in SPAST and provide an opportunity to further study the genotype-phenotype correlation of SPG4.

SPG9A with the new occurrence of an ALDH18A1 mutation in a CMT1A family with PMP22 duplication: case report.

BACKGROUND: ALDH18A1 mutations lead to delta-1-pyrroline-5-carboxylate-synthetase (P5CS) deficiency, which is a urea cycle-related disorder including SPG9A, SPG9B, autosomal dominant cutis laxa-3 (ADCL3), and autosomal recessive cutis laxa type 3A (ARCL3A). These diseases exhibit a broad clinical spectrum, which makes the diagnosis of P5CS deficiency difficult. We report here a rare Japanese family including both patients with an ALDH18A1 mutation (SPG9A) and ones with CMT1A. CASE PRESENTATION: A Japanese family included five patients with the CMT phenotype and five with the HSP phenotype in four generations. The patients with the HSP phenotype showed a pure or complicated form, and intrafamilial clinical variability was noted. Genetically, FISH analysis revealed that two CMT patients had a PMP22 duplication (CMT1A). Exome analysis and Sanger sequencing revealed five HSP patients had an ALDH18A1 heterozygous mutation of c.755G > A, which led to SPG9A. Haplotype analysis revealed that the ALDH18A1 mutation must have newly occurred. To date, although de novo mutations of ALDH18A1 have been described in ADCL3A, they were not mentioned in SPG9A in earlier reports. Thus, this is the first SPG9A family with a de novo mutation or the new occurrence of gonadal mosaicism of ALDH18A1. Analysis of serum amino acid levels revealed that two SPG9A patients and two unaffected family members had low citrulline levels and one had a low level of ornithine. CONCLUSIONS: Since the newly occurring ALDH18A1 mutation, c.755G > A, is the same as that in two ADHSP families and one sporadic patient with SPG9A reported previously, this genomic site might easily undergo mutation. The patients with the c.755G > A mutation in our family showed clinical variability of symptoms like in the earlier reported two families and one sporadic patient with this mutation. Further studies are required to clarify the relationship between the amino acid levels and clinical manifestations, which will reveal how P5CS deficiency influences disease phenotypes including ARCL3A, ADCL3, SPG9B, and SPG9A.

Variants in saposin D domain of prosaposin gene linked to Parkinson's disease.

Recently, the genetic variability in lysosomal storage disorders has been implicated in the pathogenesis of Parkinson's disease. Here, we found that variants in prosaposin (PSAP), a rare causative gene of various types of lysosomal storage disorders, are linked to Parkinson's disease. Genetic mutation screening revealed three pathogenic mutations in the saposin D domain of PSAP from three families with autosomal dominant Parkinson's disease. Whole-exome sequencing revealed no other variants in previously identified Parkinson's disease-causing or lysosomal storage disorder-causing genes. A case-control association study found two variants in the intronic regions of the PSAP saposin D domain (rs4747203 and rs885828) in sporadic Parkinson's disease had significantly higher allele frequencies in a combined cohort of Japan and Taiwan. We found the abnormal accumulation of autophagic vacuoles, impaired autophagic flux, altered intracellular localization of prosaposin, and an aggregation of α-synuclein in patient-derived skin fibroblasts or induced pluripotent stem cell-derived dopaminergic neurons. In mice, a Psap saposin D mutation caused progressive motor decline and dopaminergic neurodegeneration. Our data provide novel genetic evidence for the involvement of the PSAP saposin D domain in Parkinson's disease.

Defining the clinical, molecular and imaging spectrum of adaptor protein complex 4-associated hereditary spastic paraplegia.

Bi-allelic loss-of-function variants in genes that encode subunits of the adaptor protein complex 4 (AP-4) lead to prototypical yet poorly understood forms of childhood-onset and complex hereditary spastic paraplegia: SPG47 (AP4B1), SPG50 (AP4M1), SPG51 (AP4E1) and SPG52 (AP4S1). Here, we report a detailed cross-sectional analysis of clinical, imaging and molecular data of 156 patients from 101 families. Enrolled patients were of diverse ethnic backgrounds and covered a wide age range (1.0-49.3 years). While the mean age at symptom onset was 0.8 ± 0.6 years [standard deviation (SD), range 0.2-5.0], the mean age at diagnosis was 10.2 ± 8.5 years (SD, range 0.1-46.3). We define a set of core features: early-onset developmental delay with delayed motor milestones and significant speech delay (50% non-verbal); intellectual disability in the moderate to severe range; mild hypotonia in infancy followed by spastic diplegia (mean age: 8.4 ± 5.1 years, SD) and later tetraplegia (mean age: 16.1 ± 9.8 years, SD); postnatal microcephaly (83%); foot deformities (69%); and epilepsy (66%) that is intractable in a subset. At last follow-up, 36% ambulated with assistance (mean age: 8.9 ± 6.4 years, SD) and 54% were wheelchair-dependent (mean age: 13.4 ± 9.8 years, SD). Episodes of stereotypic laughing, possibly consistent with a pseudobulbar affect, were found in 56% of patients. Key features on neuroimaging include a thin corpus callosum (90%), ventriculomegaly (65%) often with colpocephaly, and periventricular white-matter signal abnormalities (68%). Iron deposition and polymicrogyria were found in a subset of patients. AP4B1-associated SPG47 and AP4M1-associated SPG50 accounted for the majority of cases. About two-thirds of patients were born to consanguineous parents, and 82% carried homozygous variants. Over 70 unique variants were present, the majority of which are frameshift or nonsense mutations. To track disease progression across the age spectrum, we defined the relationship between disease severity as measured by several rating scales and disease duration. We found that the presence of epilepsy, which manifested before the age of 3 years in the majority of patients, was associated with worse motor outcomes. Exploring genotype-phenotype correlations, we found that disease severity and major phenotypes were equally distributed among the four subtypes, establishing that SPG47, SPG50, SPG51 and SPG52 share a common phenotype, an 'AP-4 deficiency syndrome'. By delineating the core clinical, imaging, and molecular features of AP-4-associated hereditary spastic paraplegia across the age spectrum our results will facilitate early diagnosis, enable counselling and anticipatory guidance of affected families and help define endpoints for future interventional trials.

RFC1 repeat expansion in Japanese patients with late-onset cerebellar ataxia.

Recently, the expansion of an intronic AAGGG repeat in the replication factor C subunit 1 (RFC1) gene was reported to cause cerebellar ataxia, neuropathy, vestibular areflexia syndrome (CANVAS). In Europeans, the expansion accounted for 22% of sporadic patients with late-onset ataxia. We genotyped 37 Japanese patients comprising 25 familial (autosomal recessive or undecided transmission) and 12 sporadic ones with late-onset ataxia. We found intronic repeat expansions in RFC1 in three (12%) of the familial patients and one (8.5%) of the sporadic ones. Although our cohort study was small, the disease frequency in Japanese patients with CANVAS might be lower than that in European ones. In addition, we found biallelic ACAGG repeat expansion in one patient, indicating ACAGG repeat expansion might cause CANVAS. Clinically, we found one patient with sleep apnea syndrome, which has not been reported previously. Thus, this study might expand the clinical and genetic spectrum of CANVAS.

Sympathetic outflow to skin predicts central autonomic dysfunction in multiple system atrophy.

BACKGROUND: To find out the physiological method for evaluating the severity of central autonomic dysfunction, we performed detailed evaluation of cutaneous vasomotor neural function in a comparatively large sample of multiple system atrophy (MSA). METHODS: We evaluated cutaneous vasomotor neural function in 24 MSA patients. Skin sympathetic nerve activity (SSNA) and sympathetic skin response (SSR) and skin blood flow (skin vasomotor reflex [SVR]) were recorded at rest, as well as reflex changes after electrical stimulation. The parameters investigated were SSNA frequency at rest, reflex latency and amplitude of SSNA reflex bursts, absolute decrease and percent reduction of SVR, recovery time, and spontaneous SVR and SSR frequency. RESULTS: There were negative correlations between resting SSNA and disease duration or the SCOPA-AUT score, but these were not significant. SSNA reflex latency displayed significant positive correlations with disease duration and SCOPA-AUT score (p < 0.001 and p < 0.01, respectively). In all five patients who underwent the same examination twice, SSNA reflex latency was significantly longer at the second examination than at the first examination (p < 0.005). A significant positive correlation was identified between recovery time of skin blood flow and SCOPA-AUT score or reflex latency (p < 0.05). Significant correlations were not observed between SCOPA-AUT score or disease duration and other parameters. CONCLUSIONS: These results suggest that some MSA patients with a comparatively short duration of disease potentially have impaired thermoregulatory function. Measurement of sympathetic outflow to the skin is potentially a useful tool for predicting the severity of central autonomic dysfunction in MSA.

UBAP1 mutations cause juvenile-onset hereditary spastic paraplegias (SPG80) and impair UBAP1 targeting to endosomes.

We aimed to find a new causative gene and elucidate the molecular mechanisms underlying a new type of hereditary spastic paraplegia (HSP). Patients with HSP were recruited from the Japan Spastic Paraplegia Research Consortium (JASPAC). Exome sequencing of genomic DNA from patients in four families was carried out, followed by Sanger sequencing of the UBAP1 gene. A mouse homolog of one UBAP1 frameshift mutation carried by one of the patients was created as a disease model. Functional properties of the UBAP1 wild type and UBAP1-mutant in mouse hippocampus neurons were examined. We identified three novel heterozygous loss of function mutations (c.425_426delAG, c.312delC, and c.535G>T) in the UBAP1 gene as the genetic cause of a new type of HSP (SPG80). All the patients presented identical clinical features of a pure type of juvenile-onset HSP. Functional studies on mouse hippocampal neurons revealed that the C-terminal deletion UBAP1-mutant of our disease model had lost its ability to bind ubiquitin in vitro. Overexpression of the UBAP1 wild type interacts directly with ubiquitin on enlarged endosomes, while the UBAP1-mutant cannot be recruited to endosome membranes. Our study demonstrated that mutations in the UBAP1 gene cause a new type of HSP and elucidated its pathogenesis. The full-length UBAP1 protein is involved in endosomal dynamics in neurons, while loss of UBAP1 function may perturb endosomal fusion and sorting of ubiquitinated cargos. These effects could be more prominent in neurons, thereby giving rise to the phenotype of a neurodegenerative disease such as HSP.

Correction: PLA2G6-associated neurodegeneration presenting as a complicated form of hereditary spastic paraplegia.

The originally published version of this article contained an error in Fig. 1 and Table 2. The correct figure and table of this article should have read as below. This has now been corrected in the PDF and HTML versions of the article. The authors apologize for any inconvenience caused.

A novel homozygous mutation of the TFG gene in a patient with early onset spastic paraplegia and later onset sensorimotor polyneuropathy.

The tropomyosin-receptor kinase fused gene (TFG) has recently been implicated in several distinct hereditary disorders, including the autosomal-recessive form of complicated hereditary spastic paraplegia called SPG57. Previously, three homozygous variants of the TFG gene were reported in five families with SPG57, in which early onset spastic paraplegia, optic atrophy, and peripheral neuropathy were variably identified. Here, we present the first Japanese patient with SPG57, and have added a homozygous p.Ile66Thr variant as the fourth SPG57 genotype.

PLA2G6-associated neurodegeneration presenting as a complicated form of hereditary spastic paraplegia.

PLA2G6-associated neurodegeneration (PLAN) comprises heterogeneous neurodegenerative disorders, including infantile neuroaxonal dystrophy, neurodegeneration with brain iron accumulation 2B, and Parkinson disease 14 (PARK14). In addition, very recently, PLA2G6 mutations have been reported to represent a phenotype of hereditary spastic paraplegia (HSP). In this study, we screened 383 HSP families to clarify the frequency of PLA2G6 mutations in the Japan Spastic Paraplegia Research Consortium, and revealed the clinical characteristics of HSP with PLA2G6 mutations. We found three families with compound heterozygous mutations of the PLA2G6 gene, c.517 C > T/c.1634A > G, c.662 T > C/c.991 G > T, and c.1187-2 A > G/c.1933C > T, and one family with a homozygous mutation of the PLA2G6 gene, c.1904G > A/c.1904G > A. All three families with compound heterozygous mutations presented a uniform phenotype of a complicated form of HSP with infantile/child-onset spastic paraplegia, cerebellar ataxia, and mental retardation. On the other hand, the family with a homozygous mutation presented a late-onset complicated form of HSP with parkinsonism. This study may extend the clinical and genetic findings for PLAN.

Spinocerebellar ataxia type 31 associated with REM sleep behavior disorder: a case report.

BACKGROUND: Spinocerebellar ataxia type 31 (SCA 31) is a slowly progressive neurodegenerative disorder characterized by pure cerebellar ataxia. Unlike other CAG repeat diseases, sleep-related problems have not been reported in patients with SCA 31 so far. CASE PRESENTATION: A 67-year-old woman was admitted to our hospital with dysarthria and gait disturbance after onset age of 62 years. Neurological examination revealed pure cerebellar ataxia. Genetic analysis detected expansion of a TGGAA repeat in the coding region of the BEAN/TK2 gene on chromosome 16p22.1, confirming the diagnosis of SCA 31. One year later, her husband noticed the patient talking loudly during sleep once or twice a week. Overnight polysomnography showed rapid eye movement sleep without atonia. Cardiac scintigraphy with iodine-123-labeled meta-iodobenzylguanidine revealed a low heart/mediastinum ratio, indicating reduced uptake, and a high washout rate. CONCLUSION: To our knowledge, this is the first report of a patient with SCA 31 associated with rapid eye movement sleep behavior disorder (RBD). In the future, evaluation of autonomic function, assessment of the frequency of RBD, and performance of cardiac iodine-123-labeled meta-iodobenzylguanidine scintigraphy in a larger number of SCA 31 patients could be useful to resolve important issues regarding the mechanism of RBD.

Pathological findings in a patient with non-dystrophic myotonia with a mutation of the SCN4A gene; a case report.

BACKGROUND: Non-dystrophic myotonias (NDMs) are skeletal muscle disorders involving myotonia distinct from myotonic dystrophy. It has been reported that the muscle pathology is usually normal or comprises mild myopathic changes in NDMs. We describe various pathological findings mimicking those of myotonic dystrophy (DM) in biopsied muscle specimens from a patient with NDMs with a long disease duration. CASE PRESENTATION: A 66-year-old Japanease man presented eye closure myotonia, percussion myotonia and grip myotonia together with the warm-up phenomenon and cold aggravation from early childhood. On genetic analysis, a heterozygous mutation of the SCN4A gene (c.2065 C > T, p.L689F), with no mutation of the CLCN1, DMPK, or ZNF9/CNBP gene, was detected. He was diagnosed as having NDMs. A biopsy of the biceps brachii muscle showed increasing fiber size variation, internal nuclei, chained nuclei, necrotic fibers, fiber splitting, endomysial fibrosis, pyknotic nuclear clumps and disorganized intermyofibrillar networks. Sarcoplasmic masses, tubular aggregates and ragged-red fibers were absent. CONCLUSION: It is noteworthy that the present study revealed various pathological findings resembling those seen in DM, although the pathology is usually normal or mild in NDMs. The pathological similarities may be due to muscular modification with long-standing myotonia or excessive muscle contraction based on abnormal channel activity.