Spinocerebellar degenerations in Japan: a nationwide epidemiological and clinical study

Epidemiology of ataxia and hereditary spastic paraplegia in Spain: a cross-sectional study

INTRODUCTION

Ataxia and hereditary spastic paraplegia are rare neurodegenerative syndromes. We aimed to determine the prevalence of these disorders in Spain in 2019.

PATIENTS AND METHODS

We conducted a cross-sectional, multicentre, retrospective, descriptive study of patients with ataxia and hereditary spastic paraplegia in Spain between March 2018 and December 2019.

RESULTS

We gathered data from a total of 1933 patients from 11 autonomous communities, provided by 47 neurologists or geneticists. Mean (SD) age in our sample was 53.64 (20.51) years; 982 patients were men (50.8%) and 951 were women (49.2%). The genetic defect was unidentified in 920 patients (47.6%). A total of 1371 patients (70.9%) had ataxia and 562 (29.1%) had hereditary spastic paraplegia. Prevalence rates for ataxia and hereditary spastic paraplegia were estimated at 5.48 and 2.24 cases per 100 000 population, respectively. The most frequent type of dominant ataxia in our sample was SCA3, and the most frequent recessive ataxia was Friedreich ataxia. The most frequent type of dominant hereditary spastic paraplegia in our sample was SPG4, and the most frequent recessive type was SPG7.

CONCLUSIONS

In our sample, the estimated prevalence of ataxia and hereditary spastic paraplegia was 7.73 cases per 100 000 population. This rate is similar to those reported for other countries. Genetic diagnosis was not available in 47.6% of cases. Despite these limitations, our study provides useful data for estimating the necessary healthcare resources for these patients, raising awareness of these diseases, determining the most frequent causal mutations for local screening programmes, and promoting the development of clinical trials.

Dentatorubropallidoluysian Atrophy with Prominent Autonomic Dysfunction

We herein report a 45-year-old man with dentatorubropallidoluysian atrophy (DRPLA) who presented with mild dementia, ataxia, and involuntary movement and developed constipation, dysuria, and orthostatic hypotension. Thermography revealed an abnormal thermal response of the skin to cold stimulation. Skin temperature reflects the skin blood flow and is regulated by the sympathetic nervous system. Thermography is currently used to study diseases associated with vasomotor dysfunction of the skin. The thermography results suggested the possibility of autonomic dysfunction. Although little is known regarding autonomic dysfunction in DRPLA, this report demonstrates the importance of autonomic dysfunction in DRPLA.

Glutathione Depletion and MicroRNA Dysregulation in Multiple System Atrophy: A Review

Multiple system atrophy (MSA) is a rare neurodegenerative disease characterized by parkinsonism, cerebellar impairment, and autonomic failure. Although the causes of MSA onset and progression remain uncertain, its pathogenesis may involve oxidative stress via the generation of excess reactive oxygen species and/or destruction of the antioxidant system. One of the most powerful antioxidants is glutathione, which plays essential roles as an antioxidant enzyme cofactor, cysteine-storage molecule, major redox buffer, and neuromodulator, in addition to being a key antioxidant in the central nervous system. Glutathione levels are known to be reduced in neurodegenerative diseases. In addition, genes regulating redox states have been shown to be post-transcriptionally modified by microRNA (miRNA), one of the most important types of non-coding RNA. miRNAs have been reported to be dysregulated in several diseases, including MSA. In this review, we focused on the relation between glutathione deficiency, miRNA dysregulation and oxidative stress and their close relation with MSA pathology.

Autonomic dysfunction as the initial presentation in spinocerebellar ataxia type 3: A case report and review of the literature

Spinocerebellar ataxia type 3 (SCA3), as the most frequent autosomal dominant ataxia worldwide, is characterized by progressive cerebellar ataxia, dysarthria and extrapyramidal signs. Additionally, autonomic dysfunction, as a common clinical symptom, present in the later stage of SCA3. Here, we report a 44-year-old male patient with early feature of autonomic dysfunction includes hyperhidrosis and sexual dysfunction, followed by mild ataxia symptoms. The Unified Multiple System Atrophy Rating Scale (UMSARS) indicated significant dysautonomia during autonomic function testing. Combination of early and autonomic abnormalities and ataxia would be more characteristic of the cerebellar type of multiple system atrophy (MSA-C), the patient's positive family history and identification of an ATXN3 gene mutation supported SCA3 diagnosis. To best of our knowledge, the feature as the initial presentation in SCA3 has not been described. Our study demonstrated that autonomic dysfunction may have occurred during the early stages of SCA3 disease.

Urinary Symptoms and Urodynamic Findings in Patients with Spinocerebellar Ataxia

Urinary dysfunctions are not considered symptoms of spinocerebellar ataxias (SCAs). However, given that a patient with SCAs without a family history might be misdiagnosed as MSA-C when having urinary dysfunctions, characterization of urinary dysfunctions in SCAs is needed not only to understand SCAs but also to correctly diagnosis patients with ataxia. We retrospectively reviewed medical records of 143 patients with genetically confirmed SCA1, 2, 3, 6, 7, 17, and DRPLA. Twenty-two patients (men n = 9; age 62.1 ± 10.9; disease duration 8.2 ± 2.9 years) who had lower urinary track symptoms (LUTS) were included in this study. Six patients underwent urodynamic study (UDS), and 2 underwent uroflowmetry. LUTS was present in 1 of 11 patients with SCA1, in 4 of 51 with SCA2, in 2 of 26 with SCA3, in 3 of 20 with SCA6, in 2 of 4 with SCA7, in 8 of 26 with SCA17, and in 2 of 5 with DRPLA. Overall, urinary frequency was the most common symptom (16 patients, 72.7%) followed by voiding difficulty. In three of the 6 patients with UDS, post-micturition residuals were > 100 ml. Detrusor overactivity was noted in three patients. Detrusor areflexia was observed in one. Four patients were diagnosed with a neurogenic bladder, 3 with a storage problem, and 1 with both storage and voiding problems. Fifteen percent of the patients with SCAs had LUTS, and LUTS occurred in various types of SCAs. Our results indicate that SCAs should be considered in patients with progressive cerebellar ataxia and urinary dysfunctions.

Epidemiology of ataxia and hereditary spastic paraplegia in Spain: a cross-sectional study

INTRODUCTION

Ataxia and hereditary spastic paraplegia are rare neurodegenerative syndromes. We aimed to determine the prevalence of these disorders in Spain in 2019.

PATIENTS AND METHODS

We conducted a cross-sectional, multicentre, retrospective, descriptive study of patients with ataxia and hereditary spastic paraplegia in Spain between March 2018 and December 2019.

RESULTS

We gathered data from a total of 1.809 patients from 11 autonomous communities, provided by 47 neurologists or geneticists. Mean (SD) age in our sample was 53.64 (20.51) years; 920 patients were men (50.8%) and 889 were women (49.2%). The genetic defect was unidentified in 920 patients (47.6%). A total of 1371 patients (70.9%) had ataxia and 562 (29.1%) had hereditary spastic paraplegia. Prevalence rates for ataxia and hereditary spastic paraplegia were estimated at 5.48 and 2.24 cases per 100 000 population, respectively. The most frequent type of dominant ataxia in our sample was SCA3, and the most frequent recessive ataxia was Friedreich ataxia. The most frequent type of dominant hereditary spastic paraplegia in our sample was SPG4, and the most frequent recessive type was SPG7.

CONCLUSIONS

In our sample, the estimated prevalence of ataxia and hereditary spastic paraplegia was 7.73 cases per 100 000 population. This rate is similar to those reported for other countries. Genetic diagnosis was not available in 47.6% of cases. Despite these limitations, our study provides useful data for estimating the necessary healthcare resources for these patients, raising awareness of these diseases, determining the most frequent causal mutations for local screening programmes, and promoting the development of clinical trials.

Nonmotor symptoms in spinocerebellar ataxias (SCAs)

Nonmotor symptoms (NMS) have been increasingly recognized in a number of neurodegenerative diseases with a burden of disability that parallels or even surpasses that induced by motor symptoms. As NMS have often been poorly recognized and inadequately treated, much of the most recent developments in the investigation of these disorders has focused on the recognition and quantification of NMS, which will form the basis of improved clinical care for these complex cases. NMS have been only sparsely investigated in a limited number of spinocerebellar ataxias (SCAs), particularly SCA3, and have not been systematically reviewed for other forms of SCAs. The aim of the present study was to review the available literature on the presence of NMS among different types of SCAs.

Physical therapy intervention with a low frequency of exercise for a patient with a complicated form of hereditary spastic paraplegia: a case report

[Purpose] Hereditary spastic paraplegia (HSP) is a neurodegenerative disorder characterized by progressive spasticity and weakness of the lower limbs. To date, the appropriate frequency and intensity of physical therapy for patients with HSP are not well-known. We created an original rehabilitation program for a patient with a complicated form of HSP, wherein the program required low-frequency involvement to adapt to the long-term insurance system in Japan. We wanted to find out whether this program could maintain the physical functions and activities of daily living (ADL) of the patient. [Participant and Methods] A 41-year-old male diagnosed with a complicated form of HSP with decreased visual acuity and ataxia of the trunk and upper limb underwent a specific rehabilitation program that included a squatting exercise, a kneeling position exercise, and a motion exercise of taking a bath. This intervention program lasted for 20 minutes per session, with a frequency of two days per week. The patient was in the program for 12 weeks. [Results] All outcome measures, including muscle strength (grip force and quadriceps) and Barthel index, remained unchanged at the end of the intervention program. [Conclusion] The original intervention program used in this study, which had a low frequency of exercise, was effective in preventing further regression of the lower limb function of the patient with a complicated form of HSP, and in preventing a decrease in the ability of the patient to perform ADL.

Desflurane for management of decompressive laminectomy in a patient with hereditary spastic paraplegia: a case report

BACKGROUND

Hereditary spastic paraplegia (HSP) is a rare, genetic neurodegenerative condition. Thus far, ideal anesthetic management is not established for patients with HSP; therefore, careful selection and dosage of anesthetic agents is required.

CASE PRESENTATION

A 54-year-old woman with HSP, who was diagnosed with severe lumbar spinal canal stenosis, underwent decompressive laminectomy to relieve her back pain. Preoperatively, she experienced slight difficulty in walking independently; however, she exhibited no other dysfunction. Anesthesia was maintained with desflurane after tracheal intubation. Rocuronium and sugammadex were used for neuromuscular blockade and reversal, respectively, with neuromuscular monitoring equipment. The patient showed uneventful postoperative recovery without signs of neurological deterioration after extubation.

CONCLUSIONS

Our successful experience in this case implies that, for patients with neuromuscular diseases, including HSP, desflurane may be an option for anesthetic management; moreover, careful assessment (e.g., medical condition, bispectral index, and train-of-four) should be performed prior to administration of anesthesia.

JASPAC: Japan Spastic Paraplegia Research Consortium

Hereditary spastic paraplegias (HSPs) are a group of neurodegenerative disorders characterized by weakness and spasticity of the lower extremities. HSPs are heterogeneous disorders that involve over 80 causative genes. The frequency of HSPs is estimated to be 10–100/1,000,000. With this background, the Japanese research group “Japan Spastic Paraplegia Research Consortium: JASPAC” was organized in 2006 to elucidate the molecular epidemiologies of HSPs in Japan and the molecular pathologies of HSPs. To date, the JASPAC has collected 714 HSP families and analyzed 488 index patients. We found 279 pathogenic variants or probable pathogenic variants of causative genes in the 488 HSP patients. According to our results, we found 178 families with autosomal dominant patients (65%), and 101 with autosomal recessive and sporadic patients (48%). We found 119 patients with SPG4, 17 with SPG3A, 15 with SPG31, 13 with SPG11, and 11 with SPG10. Other HSP genes were the cause in less than five patients. On the other hand, we could not find causative genes in 35% of the autosomal dominant patients, or 52% of the autosomal recessive and sporadic patients. We are now trying to find new causative genes and elucidate the molecular mechanisms underlying HSPs.

Onset of bladder and motor symptoms in multiple system atrophy: differences according to phenotype

PURPOSE

To compare the order of presentation of bladder and motor symptoms between multiple system atrophy phenotypes.

METHODS

Medical records were retrospectively reviewed in 144 patients.

RESULTS

Bladder symptoms occurred either before or within 12 months after onset of motor symptoms in significantly more patients with the cerebellar phenotype than the parkinsonian phenotype (80 vs. 53%, p = 0.003); similar results were observed for urinary incontinence (79 vs. 45%, p = 0.001).

CONCLUSIONS

Urinary dysfunction is more likely to appear either before or shortly after motor symptoms in the cerebellar phenotype than in the parkinsonian phenotype.

Hypocupremia: a possible association with late cortical cerebellar atrophy

BACKGROUND

We report a patient, diagnosed with late cortical cerebellar atrophy, who had persistent low serum copper levels.

CASE REPORT

A 48-year-old male developed progressive difficulty with balance, frequent falls, and dysarthric speech, which worsened over a short time span. He had an extensive ataxia work-up, which was unremarkable except for persistent low serum copper levels despite adequate supplementation. Magnetic resonance imaging of the brain showed marked cerebellar atrophy. The patient experienced progressive worsening of symptoms, which did not improve with either oral or parenteral copper supplementation.

DISCUSSION

To our knowledge, ours is the first case report of late cortical cerebellar atrophy in the setting of low serum copper levels. The current report should trigger further research in mechanisms leading to copper deficiency and its possible role in cerebellar disease.

Machado-Joseph disease in a Nigerian family: mutational origin and review of the literature

Machado-Joseph disease (MJD) has been described in Africans, but no cases have been reported from Nigeria. Current MJD global distribution results from both the ancestral populations-of-origin and the founder effects of mutations, some as a consequence of the Portuguese sea travels in the 15th to 16th century. Two main ancestral haplotypes have been identified: the Machado lineage, which is more recent, predominant in families of Portuguese extraction, and the Joseph lineage, which is much older and worldwide spread, postulated to have an Asian origin. We report a Nigerian family with MJD from Calabar, once settled by Portuguese slave traders, and assessed its mutational origin. The proband was a 33-year-old man with progressive unsteady gait, weakness of all limbs, dysphagia, dysarthria, urinary frequency and diaphoresis. He had end-of-gaze nystagmus, spastic quadriparesis and atrophic small muscles of the hand. He showed fibrillation potentials on EMG, and nerve conduction studies suggested a central axonopathy without demyelination. This family bears the Joseph haplotype, which has a founder effect in the island of Flores, in the Azores (and their descendants in North-America), but is also the most common in non-Portuguese populations worldwide, with an estimated mutation age of around 7000 years.

The global epidemiology of hereditary ataxia and spastic paraplegia: a systematic review of prevalence studies

BACKGROUND

Hereditary cerebellar ataxias (HCA) and hereditary spastic paraplegias (HSP) are two groups of neurodegenerative disorders that usually present with progressive gait impairment, often leading to permanent disability. Advances in genetic research in the last decades have improved their diagnosis and brought new possibilities for prevention and future treatments. Still, there is great uncertainty regarding their global epidemiology.

SUMMARY

Our objective was to assess the global distribution and prevalence of HCA and HSP by a systematic review and meta-analysis of prevalence studies. The MEDLINE, ISI Web of Science and Scopus databases were searched (1983-2013) for studies performed in well-defined populations and geographical regions. Two independent reviewers assessed the studies and extracted data and predefined methodological parameters. Overall, 22 studies were included, reporting on 14,539 patients from 16 countries. Multisource population-based studies yielded higher prevalence values than studies based primarily on hospitals or genetic centres. The prevalence range of dominant HCA was 0.0-5.6/10(5), with an average of 2.7/10(5) (1.5-4.0/10(5)). Spinocerebellar ataxia type 3 (SCA3)/Machado-Joseph disease was the most common dominant ataxia, followed by SCA2 and SCA6. The autosomal recessive (AR) HCA (AR-HCA) prevalence range was 0.0-7.2/10(5), the average being 3.3/10(5) (1.8-4.9/10(5)). Friedreich ataxia was the most frequent AR-HCA, followed by ataxia with oculomotor apraxia or ataxia-telangiectasia. The prevalence of autosomal dominant (AD) HSP (AD-HSP) ranged from 0.5 to 5.5/10(5) and that of AR-HSP from 0.0 to 5.3/10(5), with pooled averages of 1.8/10(5) (95% CI: 1.0-2.7/10(5)) and 1.8/10(5) (95% CI: 1.0-2.6/10(5)), respectively. The most common AD-HSP form in every population was spastic paraplegia, autosomal dominant, type 4 (SPG4), followed by SPG3A, while SPG11 was the most frequent AR-HSP, followed by SPG15. In population-based studies, the number of families without genetic diagnosis after systematic testing ranged from 33 to 92% in the AD-HCA group, and was 40-46% in the AR-HCA, 45-67% in the AD-HSP and 71-82% in the AR-HSP groups.

KEY MESSAGES

Highly variable prevalence values for HCA and HSP are reported across the world. This variation reflects the different genetic make-up of the populations, but also methodological heterogeneity. Large areas of the world remain without prevalence studies. From the available data, we estimated that around 1:10,000 people are affected by HCA or HSP. In spite of advances in genetic research, most families in population-based series remain without identified genetic mutation after extensive testing. © 2014 S. Karger AG, Basel.

[Japan spastic paraplegia research consortium (JASPAC)]

Japan Spastic Paraplegia Research Consortium (JASPAC), a nationwide clinical and genetic survey of patients with HSP in Japan, was started from 2006 as a project of the Research Committee for Ataxic Diseases of the Ministry of Health, Labor and Welfare, Japan. To date (October 4, 2010), 321 index patients with HSP have been registered from 40 prefectures in Japan. We are now performing molecular testing for the HSP patients using direct sequencing (SPG4, SPG31, and ARSACS), comparative genomic hybridization (CGH) array (SPG1/2/3A/4/5/6/7/8/10/11/13/15/17/20/21/31/33/39/42/ABCD1/alsin/SACS), and resequencing microarray (SPG1/2/3A/4/5/6/7/8/10/11/13/17/20/21/31/33/ABCD1). In 144 Japanese ADHSP families, SPG4 was the most common form, accounting for 47%, followed by SPG31 (4%), SPG3A (3%), SPG8 (1%), and SPG10 (1%). The results of molecular testing will be applicable to patients in terms of improved positive diagnosis, follow-up, and genetic counseling. Since approximately 40% of ADHSP remain unknown, we will perform high-throughput linkage analyses using SNP HiTLink (SNP High Throughput Linkage analysis system) for the identification of loci for disease-associated genes. Meanwhile, preliminary data showed that SPG11 and ARSACS were common in Japanese ARHSP families. JASPAC will contribute to elucidate the spectrum of clinical features and mutations, genotype/phenotype correlations, pathophisiology in various HSP phenotypes.

The spinocerebellar ataxias: clinical aspects and molecular genetics

Spinocerebellar ataxias (SCAs) are a highly heterogeneous group of inherited neurological disorders, based on clinical characterization alone with variable degrees of cerebellar ataxia often accompanied by additional cerebellar and noncerebellar symptoms which in most cases defy differentiation. Molecular causative deficits in at least 31 genes underlie the clinical symptoms in the SCAs by triggering cerebellar and, very frequently, brain stem dysfunction. The identification of the causative molecular deficits enables the molecular diagnosis of the different SCA subtypes and facilitates genetic counselling. Recent scientific advances are shedding light into developing therapeutic strategies. The scope of this chapter is to provide updated details of the spinocerebellar ataxias with particular emphasis on those aspects aimed at facilitating the clinical and genetic diagnoses.

[Hereditary spastic paraplegia in Japan]

The Japan Spastic Paraplegia Research Consortium (JASPAC) is conducting a nationwide clinical and genetic survey of patients with HSP in Japan. To date (July 20, 2011), 375 index patients with HSP from 42 prefectures in Japan have been registered. In 148 Japanese ADHSP families, SPG4 was the most common form, accounting for 47%, followed by SPG31 (4%), SPG3A (3%), SPG8 (1%), and SPG10 (1%). Meanwhile, preliminary data showed that SPG11 and ARSACS were common in Japanese ARHSP families. Since the genes in approximately 40% of ADHSP and 80% of ARHSP cases remain unknown, we aim to identify the new genes responsible for HSP. We are now searching for a novel gene responsible for ARHSP with optic atrophy and neuropathy. To date, non-Quebec patients with ARSACS have been found in the Mediterranean area, Europe and Japan. Although Quebec patients show a homogeneous phenotype, Japanese patients exhibit some atypical clinical features, as follows: slightly later onset than that in Quebec patients, absence of retinal hypermyelination, intellectual impairment, and lack of spasticity. Recently, we found characteristic MRI findings in eight Japanese ARSACS patients, who all exhibited linear hypointensity in the pons and a hypointense area in the middle cerebellar peduncles in T(2) weighted and FLAIR images.

Involvement of Onuf's nucleus in Machado-Joseph disease: a morphometric and immunohistochemical study

Machado-Joseph disease (MJD) is an autosomal dominant neurodegenerative disease caused by an expansion of CAG repeats in the MJD1 gene, in which lower urinary tract dysfunction is known to be the most commonly encountered autonomic failure. However, it remains unclear whether Onuf's nucleus (ON), which plays major roles in the micturition reflex and voluntary continence, degenerates during the disease process. In the present study, we conducted a morphometric and immunohistochemical study of ON, together with the lateral nuclear group (LNG) of the sacral anterior horns, in seven patients with MJD. When compared with controls, the number of lower motor neurons in both ON and LNG was significantly smaller in the MJD patients, the former being inversely correlated with the size of the expanded CAG repeats. Notably, MJD patients with a large CAG-repeat expansion showed an ON-predominant pattern of neuronal loss, while in the remaining patients, ON and LNG were affected to a similar degree, or rather an LNG-predominant pattern of neuronal loss was evident. Moreover, when adjusted for age, the degree of neuronal loss in both ON and LNG was significantly correlated with the extent of expansion of the CAG repeats. In MJD, the remaining lower motor neurons in ON often exhibited ataxin-3- or 1C2-immunoreactive (ir) neuronal intranuclear inclusions, while no pTDP-43-ir neuronal cytoplasmic inclusions were present in these neurons. In conclusion, the present findings strongly suggest that neuronal loss in ON, the degree of which is highly influenced by the extent of expansion of CAG repeats, is a consistent feature in MJD.

Physiological and focal cerebellar substrates of abnormal postural sway and tremor in alcoholic women

BACKGROUND

Posturography analysis of static balance reveals marked sway and tremor in sober alcoholic men related to anterior vermis volume but can be attenuated by simple visual or tactile cues or alterations in stance. Whether alcoholic women, whose ataxia can persist with prolonged sobriety, exhibit the same physiological signature of balance instability and relation to cerebellar vermian volume as alcoholic men or can benefit from stabilizing factors is unknown.

METHODS

Groups comprised 15 alcohol-dependent women, alcohol-free (median 3 months) and 29 control women. Groups were matched in age, demographic features, and finger movement speed and underwent balance platform testing and magnetic resonance imaging scanning.

RESULTS

Alcoholic women exhibited excessive sway path length (.6 SD), more dramatic in the anterior-posterior than medial-lateral direction. Truncal tremor, measured as peak sway velocity frequency, was disproportionately great in the 5 Hz to 7 Hz band of alcoholics. Control subjects and alcoholics exhibited sway and tremor reduction with visual, tactile, or stance-stabilizing conditions, which aided both groups equally well; thus, alcoholic women never achieved normal stability. Smaller anterior vermian volumes selectively correlated with longer sway path and higher 5 Hz to 7 Hz peak sway velocity.

CONCLUSIONS

Sway and tremor abnormalities and the selective relations between greater sway and 5 Hz to 7 Hz tremor and smaller volumes of the anterior vermis had not heretofore been described in abstinent alcoholic women. Reduction in sway and tremor with stabilizing factors indicate that adaptive mechanisms involving sensorimotor integration can be invoked to compensate for vermian-related dysfunction.

Machado-Joseph disease/SCA3 and myotonic dystrophy type 1 in a single patient

We report here, for the first time, the case of a 41-year-old man with both Machado-Joseph disease (MJD)/spinocerebellar ataxia type 3 (SCA3) and myotonic dystrophy type 1. The patient noted dysarthria at 14 years of age and unsteady gait at 30 years of age. Similar sized expansions of the CAG trinucleotide repeats in one allele of the ataxin-3 (ATXN3) gene were found in both the patient and his father, although in the other allele the length of the CAG repeats was shorter in the father compared with the patient. In the dystrophia myotonica protein kinase (DMPK) gene the CTG repeats were much more expanded in the patient compared with his father. Thus it is possible that, in the farther, the short CAG repeat in the non-expanded ATXN3 allele delayed the onset of cerebellar symptoms, and/or that the expanded CTG repeat in the DMPK gene in the patient accelerated the pathogenesis of MJD/SCA3.

Sporadic ataxias in Japan--a population-based epidemiological study

Sporadic spinocerebellar ataxias (SCAs) comprise heterogeneous diseases with poorly understood epidemiologies and etiologies. A population-based epidemiological analysis of sporadic ataxias in the Japanese population was described. The prevalence rate of SCAs in the Japanese population is estimated to be 18.5/100,000. Sporadic SCAs account for 67.2% of total SCAs including hereditary SCAs, with olivopontocerebellar atrophy (OPCA) being the most common form sporadic ataxia (64.7%). The natural history analysis conducted on the basis of International Cooperative Ataxia Rating Scale (ICARS) showed that only 33% of patients with OPCA were able to walk at least with one stick 4-5 years after the onset of OPCA, which is much less than that of patients with cortical cerebellar atrophy (CCA). Similarly, 43% of patients with OPCA were able to stand alone 4-5 years after the onset, while 76% of patients with CCA were able to stand alone at the same disease duration. A population-based epidemiological analysis should provide essential information on the natural history of SCAs.

Friedreich ataxia (FA) associated with diabetes mellitus type 1 and hyperthrophic cardiomyopathy

Progressive signs of ataxia in a eight years old girl prompted neurological investigation. The girl had unstable gait with incoordination of limb movements, impairment of position and vibratory senses, dysarthria, pes cavus, positive Babinski sign and scoliosis. At the age of fourteen the girl was referred in a comatose condition, in a severe diabetic ketoacidosis. Ataxia and hypoactive knee and ankle jerks prompted the analysis of the frataxin gene (FXN; 606829). The most common molecular abnormality: GAA trinucleotide repeat expansion in intron 1 was found with + 300 GAA repeats (1490bp) (normal individuals have 5 to 30 GAA repeat expansions, whereas affected individuals have from 70 to more than 1,000 GAA triplets). Electrocardiogram showed diffuse T wave inversion with sinus bradycardia, while ultrasound revealed concentric, symmetric hypertrophy of left ventricle leading to the diagnosis of hyperthrophic cardiomyopathy. At the age of 14 years, the patient was bound to the wheel-chair, unable to walk. Her brother started to show ataxia at the age of 8 years, and subsequent analysis showed hyperthrophic cardiomyopathy, too. His mutational analysis revealed the same frataxin abnormality, with + 300 GAA repeats. So far, no signs of diabetes occurred. The parents are heterozygous with FXN of 9 -10 GAA (490 bp). Both children received a beta blocker, while the girl's diabetes mellitus was treated by insulin preparations. This is a report of two siblings with Fridreich ataxia and hyperthrophic cardiomyopathy. In addition, the girl developed type 1 diabetes mellitus.

Prevalence of hereditary ataxia and spastic paraplegia in southeast Norway: a population-based study

A population-based, cross-sectional study was performed in southeast Norway, between January 2002 and February 2008, to identify subjects with hereditary ataxia and hereditary spastic paraplegia, and to estimate the prevalence of these disorders. Patients were recruited through colleagues, families, searches in computerized hospital archives and the National Patients' Association for Hereditary Ataxia and Spastic Paraplegia. Strict criteria were used for inclusion of familial and isolated subjects. A project neurologist examined all index subjects and clinical and genetic data were registered. The source population on January 1, 2008 was 2.63 million and the prevalence day was set as February 1, 2008. One hundred seventy-one subjects from 87 unrelated families with hereditary ataxia and 194 subjects from 65 unrelated families with hereditary spastic paraplegia were included. The total prevalence was estimated at 13.9/100 000. Hereditary ataxia prevalence in the region was estimated at 6.5/100 000: 4.2/100 000 for autosomal-dominant and 2.3/100 000 for autosomal recessive, 0.15/100 000 for Friedreich's ataxia and 0.4/100 000 for ataxia telangiectasia. Hereditary spastic paraplegia prevalence was 7.4/100 000: 5.5/100 000 for autosomal dominant-hereditary spastic paraplegia, 0.6/100 000 for autosomal recessive-hereditary spastic paraplegia and 1.3/100 000 for isolated subjects. Marked differences were found in the frequencies of hereditary ataxia subtypes compared with other countries, while those of the most common autosomal dominant-hereditary spastic paraplegia genotypes, SPG4, SPG3 and SPG31, were similar to those previously reported. Clear variations between age groups and counties were observed, but no gender differences. Mean age on prevalence day was 48 years, mean age at onset was 24 years. We present the largest population study performed on hereditary ataxia and hereditary spastic paraplegia prevalence and report a higher prevalence than expected. Better inclusion criteria and multiple search strategies may explain the observed differences.

Defective responses to DNA single- and double-strand breaks in spinocerebellar ataxia

Failure to maintain the integrity of DNA/chromatin can result in genome instability and an increased risk of cancer. The description of a number of human genetic disorders characterised not only by cancer predisposition but by a broader phenotype including neurodegeneration suggests that maintaining genome stability is also important for preserving post-mitotic neurons. The identification of genes associated with other neurodegenerative disorders provides further evidence for the importance of DNA damage response and DNA repair genes in protecting against neurodegeneration. This theme is further developed in this review.

Spinocerebellar ataxias type 1, 2 and 3: a study of heart rate variability

OBJECTIVE

To detect cardiac autonomic dysfunction, using analysis of heart rate variability in genetically defined spinocerebellar ataxias (SCA).

MATERIALS AND METHODS

Consecutive RR intervals were analyzed for time- and frequency-domain parameters in 22 genotypically proven SCA patients (SCA1 = 11, SCA2 = 6 and SCA3 = 5) and compared with that of age- and gender-matched controls.

RESULTS

Reduction in the standard deviation of RR interval (RR_SD) was seen in 72.7% of SCA patients. There was a reduction in both the parasympathetic and sympathetic parameters in SCA without any change in the ratio of low- to high-frequency power. In SCA1, there was a significant negative correlation between RR_SD and duration of illness but not with the CAG repeat lengths of the abnormal allele. Small sample size of SCA2 and SCA3 precluded similar comparison.

CONCLUSIONS

Cardiac autonomic dysfunction, predominantly parasympathetic, was seen in SCA, and the severity correlated with the duration of illness in SCA1.

Vecuronium in a patient with late cerebellar cortical atrophy

Little information is available regarding the sensitivity to neuromuscular blocking drugs in patients with spinocerebellar degeneration and associated diseases. We report the response to vecuronium in a patient with late cerebellar cortical atrophy, a nonhereditary type of cerebellar ataxia. Onset time and time to 25% recovery of T1/T0 after vecuronium 0.1 mg.kg(-1) under sevoflurane anesthesia were 156 seconds and 43 minutes, respectively. Recovery index was 27 minutes. We believe this is the first report describing a response to neuromuscular blocking drugs in this disease.

Effect of vision, touch and stance on cerebellar vermian-related sway and tremor: a quantitative physiological and MRI study

Postural balance is impaired in individuals with pathology of the anterior superior vermis of the cerebellum. Chronic alcoholism, with its known vermian pathology, provides a viable model for studying the relationship between cerebellar pathology and postural stability. Decades of separate study of recovering alcoholics and post-mortem neuroanatomical analysis have demonstrated vermian pathology but few studies have used quantitative posturography, acquired concurrently with quantitative neuroimaging, to establish whether this brain structure-function relationship is selective in vivo. Here, 30 healthy men and 39 chronic alcoholic men, abstinent from alcohol for several months, underwent MRI for volumetric quantitation of the cerebellar vermis and three comparison brain regions, the cerebellar hemispheres, supratentorial cortex and corpus callosum. All subjects also participated in an experiment involving a force platform that measured sway path length and tremor during static standing balance under four sensory conditions and two stance conditions. Three novel findings emerged: (i) sway path length, a physiological index of postural control, was selectively related to volume of the cerebellar vermis and not to any comparison brain region in the alcoholics; (ii) spectral analysis revealed sway prominence in the 2-5 Hz band, another physiological sign of vermian lesions and also selectively related to vermian volume in the alcoholics; and (iii) despite substantial postural sway in the patients, they successfully used vision, touch and stance to normalize sway and reduce tremor. The selective relationship of sway path to vermian but not lateral cerebellar volume provides correlational evidence for functional differentiation of these cerebellar regions. Improvement to virtual normal levels in balance and reduction in sway and tremor with changes in vision, touch and stance provide evidence that adaptive mechanisms recruiting sensorimotor integration can be invoked to compensate for underlying cerebellar vermian-related dysfunction.

Event-related potentials during visual S1–S2 paradigm in multiple system atrophy: relation to morphologic changes on brain MRI measurement

Although mild cognitive deficits in multiple system atrophy (MSA) have been proved on neuropsychological testing, the cognitive function in MSA has not been investigated sufficiently from an electrophysiological view point. We performed a visual Event-related potential (ERP) examination and quantitative magnetic resonance imaging (MRI) measurements on 24 MSA patients and 18 normal subjects, and investigated the relationship between the ERP abnormalities and the morphological changes of the brain in MSA patients. To elicit ERPs, we used S1-S2 task which needs frontal lobe function for execution. We found significant prolongation of P3 latency and reaction time and significant attenuation of P3 amplitude in MSA, compared with normal control values. We performed the square and linear MRI measurements on MSA and normal subjects. The cerebellum, the pons, the perisylvian cerebral area and the deep cerebral gray matter in MSA were significantly smaller than those in normal subjects. The mean value in MSA was significantly increased for the bicaudate index and Huckman number compared with those in normal subjects. In MSA, we found significant correlation between P3 latency and atrophy of the cerebellum and the pons, while we found no correlation between ERP abnormalities and quantitative MRI measurements of any other regions. Our results showed that the prolongation of visual P3 latency during S1-S2 task was significantly associated with atrophy of the cerebellum and the pons.

Double-blind crossover study of branched-chain amino acid therapy in patients with spinocerebellar degeneration

To determine whether treatment with branched-chain amino acids (BCAA) can improve the condition of patients with ataxia, a double-blind crossover study of BCAA therapy was performed in 16 patients with spinocerebellar degeneration (SCD). The patients were treated with BCAA in oral doses of 1.5, 3.0, or 6.0 g or with placebo daily for 4 weeks in each study phase. The order of treatment phases (placebo or BCAA) was assigned randomly. An International Cooperative Ataxia Rating Scale (ICARS) was used to quantify the severity of symptoms of SCD. The mean ICARS score improved significantly with BCAA treatment compared with the mean pretreatment score (p<0.01). In addition, the improvement in the mean global ICARS score was significant in the middle-dose group compared with that in the placebo group (p<0.02). The estimated improvement in kinetic functions compared with pretreatment (p<0.01) was significant after treatment with BCAA, 1.5 and 3.0 g. All of the responders manifested predominantly cerebellar symptoms, especially those with spinocerebellar ataxia type 6 (SCA6). Thus, treatment with BCAA may be effective in patients with the cerebellar form of SCD.

The prevalence of "pure" autosomal dominant hereditary spastic paraparesis in the island of Ireland

OBJECTIVES

Hereditary spastic paraparesis (HSP) is clinically and genetically heterogeneous. "Pure" autosomal dominant (AD) HSP is most common and eight genetic loci are identified to date. Previous studies have included autosomal recessive and sporadic cases in prevalence calculations. This study aimed to determine the prevalence and features of pure ADHSP in the island of Ireland.

METHODS

Index cases were identified from a 5 year survey of all adult and paediatric neurologists, clinical geneticists, hospital records, and hospital inpatient enquiry system data in Ireland, north and south. Families were examined by two neurologists and classified as affected or unaffected according to specific criteria. The prevalence date was set at 1 June 2000 and the midyear population estimate for the previous year was 5.436 million.

RESULTS

Eighty two patients with pure ADHSP and a further 12 obligate carriers from 19 families were identified. In total 69 patients with pure ADHSP were alive and resident in Ireland at the prevalence date. Twenty nine per cent of these were asymptomatic but with signs of paraparesis.

CONCLUSIONS

The prevalence of ADHSP in Ireland to estimated to be 1.27/100 000 population. The high proportion of asymptomatic cases and obligate carriers means that this condition is likely to be underdiagnosed.

Clinical and genetic analysis of hereditary and sporadic ataxia in central Italy

We have clinically and genetically evaluated 24 affected patients belonging to 22 Italian Friedreich ataxia (FA) families, 52 patients from 32 kindreds with proven autosomal dominant cerebellar ataxia (ADCA), 9 patients belonging to 5 families with autosomal recessive hereditary ataxia (ARCA) and 103 sporadic cases, 89 of which affected by idiopathic late onset cerebellar ataxia (ILOCA). Genotype-phenotype correlation analyses in FA patients have evidenced an inverse relationship between GAA repeat expansion length and age of onset, disease duration, and presence of cardiomyopathy. Among autosomal dominant types, spinocerebellar ataxia 2 (SCA2) genotype has been found in 31% of our ADCA families, resulting the most frequent form of ataxia. Phenotypic analysis of the various SCA subtypes evidenced a marked heterogeneity of symptoms with a substantial overlap between different syndromes.

Prevalence of triplet repeat expansion in ataxia patients from Hokkaido, the northernmost island of Japan

Approximately 44% of cases of spinocerebellar ataxia (SCA) in Hokkaido, the northernmost island of Japan, were estimated to be inherited. To determine the prevalence of triplet repeat expansion in hereditary SCA patients, we genotyped seven genetically defined dominant SCAs in 349 patients, including 266 patients from 77 families, 78 probands from unrelated families with hereditary late-onset SCA, and five patients in whom a family history of SCA was not demonstrated. The frequency of each disorder in a total of 155 unrelated families was 23.9% for Machado-Joseph disease (MJD), 29.0% for SCA6, 9.7% for SCA1, 7.7% for SCA2, and 2.6% for dentatorubral-pallidoluysian atrophy. Abnormal expansion of triplet repeats for SCA7 and SCA8 was not detected. A total of 27.1% of the patients had still unknown SCA mutations. In addition, the GAA repeat in the frataxin gene was not abnormally expanded in 13 early-onset SCA patients with clinical features similar to those of Friedreich ataxia. Comparison of our results with those from other centers handling SCA showed that MJD is prevalent throughout Japan, but the frequencies of other dominant SCAs differ considerably even within Japan.

Ionizing radiation and genetic risks IX. Estimates of the frequencies of mendelian diseases and spontaneous mutation rates in human populations: a 1998 perspective

This paper is focused on baseline frequencies of mendelian diseases and the conceptual basis for calculating doubling doses both of which are relevant for the doubling dose method of estimating genetic risks of exposure of human populations to ionizing radiation. With this method, the risk per unit dose is obtained as a product of three quantities, namely, the baseline frequency of the disease class under consideration, the relative mutation risk (which is the reciprocal of the doubling dose, which in turn, is calculated as a ratio of spontaneous and induction rates of mutations) and mutation component, i.e., the responsiveness of the disease class to an increase in mutation rate. The estimates of baseline frequencies of mendelian diseases that are currently used in risk estimation date back to the late 1970s. Advances in human genetics during the past two decades now permit an upward revision of these estimates. The revised estimates are 150 per 10(4) livebirths for autosomal dominants (from the earlier estimate of 95 per 10(4)), 75 per 10(4) livebirths for autosomal recessives (from 25 per 10(4)) and to 15 per 10(4) livebirths for X-linked diseases (from 5 per 10(4)). The revised total frequency of mendelian diseases is thus 240 per 10(4) livebirths and is about twice the earlier figure of 125 per 10(4) livebirths. All these estimates, however, pertain primarily to Western European and Western European-derived populations. The fact that in several population isolates or ethnic groups, some of these diseases (especially the autosomal recessives) are more common as a result of founder effects and/or genetic drift is well known and many more recent examples have come to light. These data are reviewed and illustrated with data from studies of the Ashkenazi Jewish, Finnish, French Canadian, Afrikaner and some other populations to highlight the need for caution in extrapolating radiation risks between populations. The doubling dose of 1 Gy that has been used for the past 20 years for risk estimation is based on mouse data for both spontaneous and induction rates of mutations. In extrapolating the mouse-data-based doubling dose to humans, it is assumed that the spontaneous rates in mice and humans are similar. This assumption is incorrect because of the fact that in humans, for several well-studied mendelian diseases, the mutation rate differs between the two sexes and it increases with paternal age. In estimates of spontaneous mutation rates in humans (which represent averages over both sexes), however, paternal age effects are automatically incorporated. In the mouse, these effects are expected to be much less (if they exist at all), but the problem has not been specifically addressed. The complexities and uncertainties associated with assessing the potential impact of spontaneous mutations which arise as germinal mosaics (and which can result in clusters of mutations in the following generation) on mutation rate estimates (in the mouse) and on mutation rate estimates and disease frequencies (in humans) are discussed. In view of (i) the lack of comparability of spontaneous mutation rates in mice and humans and (ii) the fact that these estimates for human genes already include both paternal age effects and correction for clusters (if they had occurred), it is suggested that a prudent procedure now is to base doubling dose calculations on spontaneous mutation rates of human genes (and induction rates of mouse genes, in the absence of a better alternative). This concept, however, is not new and was used by the US National Academy's Committee on the Biological Effects of Ionizing Radiation in its 1972 report.

SCA6 mutation analysis in a large cohort of the Japanese patients with late-onset pure cerebellar ataxia

Spinocerebellar ataxia type 6 (SCA6) is caused by small CAG repeat expansion in the gene encoding the alpha1A-voltage-dependent-calcium channel subunit (CACNLIA4) on chromosome 19p13, and is a subgroup of the late-onset pure cerebellar ataxia (ADCA III). To investigate the prevalence of SCA6 in the Japanese, we analyzed this mutation in 23 families and 12 probands with ADCA III. The specificity and stability of the CAG repeat were examined in additional individuals and families with other miscellaneous dominant SCAs. The CAG expansion of SCA6 gene was exclusively observed in 12 of 23 families (52%) and 12 proband cases with ADCA III, but not in others. The CAG repeat was 21-33 in the disease-associated alleles (n=56), and 4-18 in normal alleles (n=1148). Expanded alleles were stable during transmission, and a significant inverse correlation for CAG repeat number with age at onset was noted. Our results indicate that SCA6 shares approximately half of the ADCA III in the Japanese, and that gene mutations causing the remaining, have yet to be identified.

Clinical and molecular genetic study in seven Japanese families with spinocerebellar ataxia type 6

We report on seven Japanese families with spinocerebellar ataxia type 6 (SCA6) carrying small CAG repeat expansions in the calcium channel alpha1A subunit gene. The number of the expanded CAG repeat, ranged from 22 to 25, showed no intergenerational instability and had a significant inverse correlation with the age of onset. The clinical features of these patients were late onset progressive pure cerebellar ataxia with dysarthria and nystagmus, and are consistent with autosomal dominant cerebellar ataxia type III (ADCA type III). Magnetic resonance imaging scan of the brain demonstrated cerebellar atrophy with no evidence of brainstem involvement. We propose that clinical phenotype of SCA6 is compatible with ADCA type III and SCA6 is one of the most common types of ADCA in Japan.

Progressive atrophy of cerebellum and brainstem as a function of age and the size of the expanded CAG repeats in the MJD1 gene in Machado-Joseph disease

Machado-Joseph disease (MJD) is an autosomal dominant neurodegenerative disease characterized by cerebellar ataxia associated to varying degrees with pyramidal signs, extrapyramidal signs, or peripheral amyotrophy. It is caused by unstable expansion of the CAG repeat in the MJD1 gene on chromosome 14q32.1. To determine how the neurodegenerative process in the central nervous system of patients with MJD correlates with the size of expanded CAG repeats in the MJD1 gene and other factors, we performed detailed quantitative analyses of findings of magnetic resonance imaging of the central nervous system of 21 patients with MJD of various ages and with various sizes of expanded CAG repeats. We found that atrophy of the brainstem and cerebellar vermis in MJD patients is closely correlated not only with the size of expanded CAG repeat in the MJD1 gene but also with patient age, which suggests that the neurodegenerative process in MJD is regulated by the size of expanded CAG repeats as well as by the patient age.

Molecular genetics of the hereditary ataxias

One of us (MP) learned about the mapping of Huntington disease gene to chromosome 4 from the late Dr. Anita Harding. She got the news over the phone from her London office during a visit to Italy for a meeting on hereditary ataxias. In Britain, they receive Nature at least a week earlier than us. Dr. Harding was very excited, and she immediately said that that was the way to go if we wanted to understand the causes of hereditary ataxias, classify these diseases in a rational way, and eventually find a treatment. At that time, the challenge seemed, and indeed was, formidable. No clue was then available about the genetic basis of what Dr. Harding aptly called "hereditary ataxias of unknown cause," their classification was confused and controversial, and all attempts to find specific biochemical abnormalities had failed. Fourteen years later, the success of the molecular genetic studies is astounding. The defective genes have been identified for Friedreich ataxia, the major recessive "hereditary ataxia of unknown cause," and for five dominantly inherited "hereditary ataxias of unknown cause." Three more dominant ataxia genes have been mapped. The molecular pathogenesis of the dominant ataxias begins to be unraveled and animal models have been and are being developed. Information is also quickly accumulating about the defective protein in Friedreich ataxia. Direct molecular diagnosis is now possible. Classification has been revolutionized. Diagnostic criteria are being redefined in the light of the molecular discoveries. The goal of this review, dedicated to the memory of the late Dr. Harding, is to offer a concise summary of current knowledge about the molecular genetics of some of the hereditary ataxias that used to be classified as of "unknown cause."

Hereditary ataxias and spastic paraplegias: methodological aspects of a prevalence study in Portugal

A project for studying the prevalence of hereditary ataxias (HA) and familial spastic paraplegias (FSP) in Portugal was set up in 1993. The ascertainment of patients in previous prevalence studies relied mainly on the information of hospital admissions and out-patient contacts with the neurology and other related departments at central hospitals covering the whole region surveyed. Many patients might be overlooked if large populations were studied using this method, since registers at central hospitals are very incomplete and for most part not yet computerized. On the other hand HA and FSP are rare diseases appearing in family clusters, and it would be unreasonable to undertake a sample survey based upon a suitable frame of the Portuguese population. Therefore we decided to carry out a two-phase prevalence survey at district level, involving the collaboration of all physicians working in the district health institutions and the population, in the screening of eligible subjects in phase 1. All subjects screened as positive were examined by a neurologist in phase 2. This method provided a direct estimate of false positives and false negatives were all patients also examined in phase 2, who came to our knowledge using other sources of information. The prevalence of hereditary ataxias and spastic paraplegias in the pilot district was 6.4 per 100,000 inhabitants. The sensitivity of the screening procedure was 81.2% and the predictive value of a positive screening was 25%. Considering the geographically circumscribed district nature of the populations to be studied, the comprehensive sources of case identification used and the high adherence of the health professionals involved, we believe that this method can be widely used, particularly in countries with similar health care services.