Identification of five Spinocerebellar Ataxia Type 2 pedigrees in patients with autosomal dominant cerebellar ataxia in Taiwan

OBJECTIVES: The autosomal dominant cerebellar ataxias (ADCAs) are a group of genetically diverse neurological conditions linked by progressive deterioration in balance and coordination. Spinocerebellar Ataxia Type 2 (SCA2) is one of the ADCAs and also belongs to a special group caused by the expansion of an unstable CAG repeat encoding a polyglutamine tract. We aimed to investigate the frequency of SCA2 mutation in the ataxia patients referred to the clinic. MATERIALS AND METHODS: We screened 58 families with inherent cerebellar ataxia and 57 normal individuals by the use of radioactive genomic polymerase chain reaction (PCR) method. A simple non-radioactive PCR for rapid detection of the expanded SCA2 alleles via agarose gel electrophoresis was also employed. RESULTS: Eight SCA2 affected patients and 1 at-risk individual in 5 unrelated SCA2 families were identified. The CAG repeats of normal alleles in the sample studied range in size from 16 to 30 repeat units, while those of SCA2 chromosomes are expanded to 34 to 49 repeat units. Our results also showed that unlike SCA 1 and SCA3/MJD, the size distribution of the normal alleles showed few polymorphisms, with the 22 repeat allele accounting for 90.1%. Homozygosity in normal individuals was 80.2%. No overlap in ataxin-2 allele size between normal and expanded chromosomes was observed. CONCLUSION: This is the first report of the SCA2 gene distributions in the population of Taiwan. The SCA2 mutation accounts for 8.6% of ADCA type I families referred to us, intermediate between SCA1(1.7%) and SCA3/MJD (24%) of the ADCA type I families in our collection.     

Absence of mutations in ATM, the gene responsible for ataxia telangiectasia in patients with cerebellar ataxia

Ataxia-telangiectasia (AT) is an autosomal recessive multisystent disorder presenting in childhood with progressive cerebellar ataxia, oculocutaneous telangiectasia, immune deficiency, radiosensitivity, and cancer predisposition. The gene for AT, designated ATM (AT, mutated) encodes a protein with a carboxy-terminal phosphoinositide-3 kinase domain which is involved in cell cycle checkpoints and other responses to genotoxic stress. Most of the patients with the classical AT phenotype are homozygous or compound heterozygous for severe mutations causing truncation or destabilization of the ATM protein. Patients with a milder forms of disease, called AT variants, have been found to be either homozygous for milder mutations or compound heterozygotes for null alleles and mild mutations. In order to define the clinical phenotype of patients homozygous (or compound heterozygotes) for other, milder mutations, we decided to search for ATM mutations in patients with either sporadic or familial idiopathic ataxia. Thirty-four patients with idiopathic cerebellar ataxia, aged 3–77 years, were screened for mutations in the ATM coding region. There were 12 familial cases. None of the patients had abnormal immunoglobulin or α-fetoprotein levels, and none had mutations in the ATM coding region. In this heterogeneous group of patients with cerebellar ataxia we found no mutations in the ATM gene. We conclude that mutations in the ATM gene are probably not a common cause for cerebellar ataxia other than AT. Received: 29 October 1998 Received in revised form: 5 February 1999 Accepted: 7 February 1999     

Acute cerebellar ataxia in the Netherlands: A study on the association with vaccinations and varicella zoster infection

Aim

Acute cerebellar ataxia (ACA, sudden onset of truncal ataxia and gait disturbances) usually follows a benign illness (25% varicella). It is also described after vaccination, like MMR and varicella zoster virus (VZV). We will establish incidence rates of (varicella related) ACA and assess the attributable risk of vaccination to ACA in the Netherlands.

Method

Data on ACA in children, following infections, like varicella, and vaccinations, obtained from prospective, active pediatric surveillance and passive surveillance on adverse events following immunizations (AEFI) were compared with hospitalization data for ataxia. Capture–recapture (CRC) method was used to estimate the burden of ACA in the Netherlands.

Results

45 children with ACA were included (44 and 1 reported by pediatric and AEFI surveillance respectively, 30 were hospitalized). Chickenpox preceded ACA in 15 cases, one case followed MMR. Of the hospitalization reports, 13 fulfilled the criteria for ACA. Using CRC the estimated number of hospitalized ACA cases was 42. For varicella related ACA, this estimate was 10, resulting in an incidence rate of 0.7:100,000 (95%CI 0.52–0.94, all cases) and 0.17:100,000 (95%CI 0.09–0.31, varicella related cases) for children under 15 years of age.

Conclusion

The incidence rates were comparable with other studies. We found no association with MMR, but chickenpox was clearly related to ACA. According to age-specific seroprevalence data the incidence rate of ACA was 5:100,000 VZV infections for children up to 5 years, compared to an ACA-reporting rate of 0.15:100,000 doses VZV-vaccine. Therefore, uptake of VZV-vaccine in the immunization programme will diminish the incidence rate of ACA.     

A clinical and neurophysiological motor signature of Unverricht–Lundborg disease

Objectives

Unverricht–Lundborg disease (ULD) is the most common form of progressive myoclonus epilepsy. Cerebellar dysfunction may appear over time, contributing along with myoclonus to motor disability. The purpose of the present work was to clarify the motor and neurophysiological characteristics of ULD patients.

3-Acetylpyridine neurotoxicity in mice

3-acetylpyridine (3-AP) is a metabolic antagonist used in research to decrease levels of nicotinamide (niacinamide) in laboratory animals. The administration of 3-AP followed by nicotinamide to rats leads to the selective destruction of neurons in the medial inferior olive, resulting in a loss of climbing fibers innervating cerebellar Purkinje cells and a consequent ataxia manifest by alterations in both balance and gait. Although 3-AP has also been administered to mice to destroy neurons in the inferior olive, there are limited studies quantifying the consequent effects on balance, and no studies on gait. Further, the relationship between 3-AP-induced lesions of the inferior olive and behavior has not been elucidated. Because 3-AP continues to be used for experiments involving mice, this study characterized the effects of this toxin on both balance and gait, and on the neuronal integrity of several brain regions involved in motor coordination. Results indicate that C57BL/6 mice are less sensitive to the neurotoxic effects of 3-AP than rats, and a dose more than 6.5 times that used for rats produces deficits in both balance and gait comparable to those in rats. This dose led to a significant (p < 0.05) loss of NeuN(+) neurons in several subregions of the inferior olive including the rostral medial nucleus, dorsomedial cell column, ventrolateral protrusion, and cap of Kooy. Further, the number of NeuN(+) neurons in these subregions, with the exception of the dorsomedial cell column, was significantly (p < 0.05) related to rotorod performance, implicating their involvement in this behavior.     

Le cervelet comme acteur majeur dans les troubles moteurs des syndromes autistiques

Scientific background

Autism spectrum disorders (ASD) are neurodevelopmental disorders associated with disturbances in communication, social interactions, cognition and affect. ASD are also accompanied by complex movement disorders, including ataxia. A special focus of recent research in this area is made on the striatum and the cerebellum, two structures known not only to control movement but also to be involved in cognitive functions such as memory and language. Dysfunction within the motor system may be associated with abnormal movements in ASD that are translated into ataxia, abnormal pattern of righting, gait sequencing, development of walking, and hand positioning. This line of study may generate new knowledge and understanding of motor symptoms associated with ASD and aims to deliver fresh perspectives for early diagnosis and therapeutic strategies against ASD.

Spinocerebellar ataxia and hypergonadotropic hypogonadism associated with familial sensorineural hearing loss

Cerebellar ataxia has been described as being associated with hypogonadism for almost 100 years. In the majority of cases, hypogonadism is hypogonadotropic. The association of cerebellar ataxia with hypergonadotropic hypogonadism is a rare genetic disorder with a recessive mode of inheritance. Cerebellar ataxia and hypogonadism can also occur associated with a large spectrum of additional clinical manifestations, including mental retardation, sensorineural deafness, choroidal dystrophy, ectodermal dysplasia and short stature, and polyneuropathy. We report the case of a woman with early-onset spinocerebellar ataxia, primary amenorrhea due to hypergonadotropic hypogonadism, and late-onset sensorineural hearing loss. Additional family members from the father's side are affected with late-onset hearing loss, suggesting a dominant mode of inheritance.     

SCA14 in Norway, two families with autosomal dominant cerebellar ataxia and a novel mutation in the PRKCG gene

Koht J, Stevanin G, Durr A, Mundwiller E, Brice A, Tallaksen CME. SCA14 in Norway, two families with autosomal dominant cerebellar ataxia and a novel mutation in the PRKCG gene.
Acta Neurol Scand: 2012: 125: 116–122.
© 2011 John Wiley & Sons A/S. Objectives – Despite a similar prevalence of autosomal dominant cerebellar ataxia (ADCA) in Norway compared to other European countries, less than 10% of the families are explained by the CAG trinucleotide expansions. We wanted to find the occurence of SCA14 in the dominant ataxia population and describe the phenotype. Methods – We screened a large dominant cerebellar ataxia cohort for mutations in the PRKCG gene. Patients were evaluated according to a standard clinical protocol for ataxia patients. Results – A novel mutation was found in two families, a C to A transversion altering Histidine to a Glutamine at codon 139, located in a highly concerved region in the gene. It completely co‐segregated with the affected family members and was not seen in 576 control chromosomes. Genetic analysis revealed common alleles at three microsatellite markers between these two families suggesting a shared ancestral chromosome. Affected subjects displayed a mild, slowly progressive cerebellar syndrome that included gait and limb ataxia and saccadic pursuit and head tremor in one. Age at onset ranged from 10 to 45 years. Conclusions – These are the first families with SCA14 reported from Scandinavia and a new mutation in the PRKCG gene. The occurrence in the Norwegian dominant ataxia cohort is 3.5%.     

Ataxia and peripheral neuropathy: rare manifestations in Henoch-Schönlein purpura

Henoch-Sch?nlein purpura (HSP) is a multisystemic vasculitis. Nervous system involvement is usually underestimated. Headaches, mental status changes and seizures are the most frequent neurologic symptoms. Ataxia and mononeuropathy are both very rare. We present an 11-year-old boy with HSP who suffered from ataxia during the initial presentation and peripheral neuropathy at the time of a relapse. Brainstem vasculitic involvement was shown by magnetic resonance imaging, while cranial tomography was normal. All the neurologic symptoms and signs resolved following bolus methylprednisolone administration. Ten months later he had a second course of HSP with skin and renal involvement. A percutaneous renal biopsy, which was performed due to persistent hematuria, revealed mesangial proliferation with IgA deposition. During that period the patient experienced pain and numbness in the right foot and leg; electromyography showed signs of mononeuritis multiplex involving the right posterior tibial nerve. The patient responded to steroid therapy. Received: 21 March 2001 / Revised: 16 July 2001 / Accepted: 18 July 2001     

Exclusion/confirmation of Ataxia-telangiectasia via cell-cycle testing

Ataxia telangiectasia (AT) is an autosomal recessive multisystem disorder with increased radiosensitivity and cancer susceptibility. The responsible gene (ATM) consists of 66 exons and a coding region of 9171 bp which precludes direct sequencing as a screening assay for confirmation or exclusion of the clinical suspicion of AT. Peripheral blood mononuclear cells of 330 patients referred for the exclusion of AT were exposed to ionizing radiation (IR) and incubated for 72 h in the presence of phytohemagglutinin. Using bivariate BrdU-Hoechst/ethidium bromide flowcytometry, the following cell cycle parameters were ascertained: (1) proportion of non-proliferating (G0,G1) cells as a measure of mitogen response, (2) proportion of first-cycle G2-phase cells relative to the growth fraction (G2/GF) as a measure of radiosensitivity. Of the cases tested, 94.2% could be unequivocally assigned either to the AT-negative or the AT-positive group of patients. Of the AT-positive cases, 11 were confirmed by ATM mutation analysis. Nineteen cases presented with non-conclusive results, mostly due to poor mitogen response; however, a combination of cell-cycle data with serum AFP concentrations led to the exclusion of AT in all but two of the uncertain cases. Substitution of ionizing radiation by the radiomimetic bleomycin was additionally tested in a small series of patients. We conclude that cell-cycle testing complemented by serum AFP measurements fulfills the criteria as a rapid and economical screening procedure for the differential diagnosis of juvenile ataxias.