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At least 145 records · Page 8Linked to original sources
PubMed2003

Rare forms of autosomal recessive neurodegenerative ataxia.

There has been a recent explosion in knowledge regarding the genetic basis of several autosomal recessive ataxias. This article summarizes current information regarding rare forms of recessive ataxias. Friedreich's ataxia and ataxia telangiectasia are dealt with in other articles in this issue. The rarer recessive ataxias can be clinically classified as sensory and spinocerbellar ataxias, cerebellar ataxia with sensory-motor polyneuropathy, and purely cerebellar ataxias. Examples of the first category include ataxia with isolated vitamin E deficiency, abetalipoproteinemia, Refsum's disease, infantile-onset spinocerebellar ataxia, and ataxia with blindness and deafness. Examples of ataxia with sensory-motor polyneuropathy include ataxia with oculomotor apraxia 1 and 2 and spinocerebellar ataxia with neuropathy 1. Examples of purely cerebellar ataxia include autosomal recessive spastic ataxia of Charlevoix-Saguenay and ataxia with hypogonadotropic hypogonadism. This review summarizes the clinical and genetic features of these entities and concludes that the pathogenic basis of such ataxias at this time appear to involve two broad types of processes: free-radical injury and defects of DNA single- or double-strand break repair.

Cerebellar Ataxia↗
PubMed2005

Distinct phenotypes within autosomal recessive ataxias not linked to already known loci.

Autosomal recessive ataxias represent a large group of neurodegenerative disorders characterized by progressive degeneration of central and peripheral nervous systems and a genetic heterogeneity. To analyse clinical, neurophysiological and nerve biopsy findings in 14 Tunisian unrelated families showing linkage exclusion to the known autosomal recessive ataxia loci, 20 Tunisian families with a total of 73 affected subjects were selected on the presence of a clinical phenotype associating a cerebellar ataxia with retained tendon reflexes on at least the index patient. A genetic linkage study was performed with markers spanning the Friedreich ataxia, Spastic ataxia of the Charlevoix-Saguenay, Autosomal recessive ataxia associated with isolated vitamin E deficiency, Ataxia with oculomotor apraxia, Infantile onset spinocerebellar ataxia, Ataxia with Hearing Loss and Optic Atrophy, AT, ATLD, Spinocerebellar ataxia with axonal neuropathy, Cayman ataxia, Cerebellar ataxia with mental retardation optic atrophy and skin abnormalities, Salla syndrome, Marinesco-Sjögren and the Childhood Spinocerebellar Ataxia loci. Out of the 20 families, 4 showed linkage to the spastic ataxia of the Charlevoix-Saguenay locus, one to the Friedreich ataxia locus and one to the Ataxia with oculomotor apraxia locus. Linkage to all tested loci has been excluded in the 14 remaining families. These families were divided into 3 groups according to tendon reflex status in lower limbs which appear as the most obvious distinguishing clinical sign between patients and families: Group A was characterized by brisk tendon reflexes in lower limbs, group B by a homogeneous feature of tendon reflexes with the absence of ankle reflexes and brisk knee reflexes and group C by variable features of tendon reflexes in lower limbs within the same family. Haplotype analysis and Lod score calculation did not show any evidence of linkage to the 16 known loci of cerebellar ataxias. Aim of this study was to reveal the vast clinical phenotypic variability in patients with autosomal recessive ataxia not linked to known loci. Data obtained indicate that detailed clinical and neurophysiological nerve investigations will be essential in order to pool patients within homogeneous subgroups for gene mapping.

Cerebellar Ataxia↗
PubMed2003

Gluten ataxia in perspective: epidemiology, genetic susceptibility and clinical characteristics.

We previously have described a group of patients with gluten sensitivity presenting with ataxia (gluten ataxia) and suggested that this disease entity may account for a large number of patients with sporadic idiopathic ataxia. We have therefore investigated the prevalence of gluten sensitivity amongst a large cohort of patients with sporadic and familial ataxia and looked at possible genetic predisposition to gluten sensitivity amongst these groups. Two hundred and twenty-four patients with various causes of ataxia from North Trent (59 familial and/or positive testing for spinocerebellar ataxias 1, 2, 3, 6 and 7, and Friedreich's ataxia, 132 sporadic idiopathic and 33 clinically probable cerebellar variant of multiple system atrophy MSA-C) and 44 patients with sporadic idiopathic ataxia from The Institute of Neurology, London, were screened for the presence of antigliadin antibodies. A total of 1200 volunteers were screened as normal controls. The prevalence of antigliadin antibodies in the familial group was eight out of 59 (14%), 54 out of 132 (41%) in the sporadic idiopathic group, five out of 33 (15%) in the MSA-C group and 149 out of 1200 (12%) in the normal controls. The prevalence in the sporadic idiopathic group from London was 14 out of 44 (32%). The difference in prevalence between the idiopathic sporadic groups and the other groups was highly significant (P < 0.0001 and P < 0.003, respectively). The clinical characteristics of 68 patients with gluten ataxia were as follows: the mean age at onset of the ataxia was 48 years (range 14-81 years) with a mean duration of the ataxia of 9.7 years (range 1-40 years). Ocular signs were observed in 84% and dysarthria in 66%. Upper limb ataxia was evident in 75%, lower limb ataxia in 90% and gait ataxia in 100% of patients. Gastrointestinal symptoms were present in only 13%. MRI revealed atrophy of the cerebellum in 79% and white matter hyperintensities in 19%. Forty-five percent of patients had neurophysiological evidence of a sensorimotor axonal neuropathy. Gluten-sensitive enteropathy was found in 24%. HLA DQ2 was present in 72% of patients. Gluten ataxia is therefore the single most common cause of sporadic idiopathic ataxia. Antigliadin antibody testing is essential at first presentation of patients with sporadic ataxia.

Adolescent↗
PubMed1997

Friedreich's ataxia. Revision of the phenotype according to molecular genetics.

Friedreich's ataxia is an autosomal recessively inherited neurodegenerative disorder caused by expansions of an unstable GAA trinucleotide repeat in the STM7/X25 gene on chromosome 9q. We studied the (GAA)n polymorphism in 178 healthy controls and 102 patients with idiopathic ataxia. The repeat size ranged from 7 to 29 (GAA)n motifs on normal chromosomes and from 66 to 1360 trinucleotide repetitions in Friedreich's ataxia patients. Meiotic instability of expanded alleles was observed without significant differences in maternal and paternal transmissions. Thirty-six of 102 patients were typed homozygous for expanded (GAA)n alleles. Twenty-seven of these presented with the typical Friedreich's ataxia symptoms and nine patients with an atypical Friedreich's ataxia phenotype. Before molecular genetic diagnosis had been performed seven of these patients had been classified as early onset cerebellar ataxia and two as idiopathic sporadic cerebellar ataxia of late onset. In contrast, in one family with typical Friedreich's ataxia phenotype we did not find an expanded allele; this suggests that there can be either point mutations in the X25 gene on both chromosomes or locus heterogeneity in Friedreich's ataxia. The phenotypic spectrum of Friedreich's ataxia is much broader than considered before. Early onset, areflexia, extensor plantar responses and reduced vibration sense should no longer be considered essential diagnostic criteria of Friedreich's ataxia. In comparison with the non-Friedreich's ataxia group hypertrophic cardiomyopathy seems to be the only symptom specific for Friedreich's ataxia. However, it is not obligatory. The phenotype is significantly influenced by the number of GAA repeats with close genotype-phenotype relationships when the smaller of the two alleles is considered. Repeat length correlated inversely with age at onset, onset of dysarthria and progression rate. In conclusion, molecular genetic analysis appears mandatory for the diagnosis and genetic counselling of Friedreich's ataxia. The molecular genetic test should be applied not only to patients with typical Friedreich's ataxia phenotype but also in all cases of idiopathic autosomal recessive or sporadic ataxia.

Adolescent↗
PubMed2005

[Ataxias. Diagnostic procedure and treatment].

Ataxia disorders (or ataxias) include both hereditary and nonhereditary diseases of the cerebellum and spinal cord, all of which are clinically characterized by progressive ataxia. A distinction is made between ataxia disorders and focal diseases of the cerebellum (tumor, abscess, infarction, hemorrhage, demyelinating disease). Ataxias are classified according to the molecular causes, being divided into hereditary ataxias, sporadic degenerative ataxias, and acquired ataxias. The diagnostic tests to be applied should be selected to suit the individual clinical situation in each case. When a patient experiences disease onset before the age of 25 years and the disease affects only one generation autosomal recessive ataxias must be considered. If one of the patient's parents had a similar disease spinocerebellar ataxia (SCA) with a dominant autosomal mode of inheritance is probable. Patients with sporadic disease starting in adulthood may have an acquired ataxia, such as alcoholic cerebellar degeneration (ACD) or paraneoplastic cerebellar degeneration (PCD), or a sporadic degenerative ataxia, such as multiple system atrophy (MSA) or sporadic adult-onset ataxia (SAOA). Therapies based on the underlying molecular pathogenesis are available for a number of ataxia disorders.

Ataxia↗
PubMed2006

Mutations in SYNE1 lead to a newly discovered form of autosomal recessive cerebellar ataxia.

The past decade has seen great advances in unraveling the biological basis of hereditary ataxias. Molecular studies of spinocerebellar ataxias (SCA) have extended our understanding of dominant ataxias. Causative genes have been identified for a few autosomal recessive ataxias: Friedreich's ataxia, ataxia with vitamin E deficiency, ataxia telangiectasia, recessive spastic ataxia of Charlevoix-Saguenay and ataxia with oculomotor apraxia type 1 (refs. 6,7) and type 2 (ref. 8). Nonetheless, genes remain unidentified for most recessive ataxias. Additionally, pure cerebellar ataxias, which represent up to 20% of all ataxias, remain poorly studied with only two causative dominant genes being described: CACNA1A (ref. 9) and SPTBN2 (ref. 10). Here, we report a newly discovered form of recessive ataxia in a French-Canadian cohort and show that SYNE1 mutations are causative in all of our kindreds, making SYNE1 the first identified gene responsible for a recessively inherited pure cerebellar ataxia.

Adult↗
PubMedDate not supplied

[Autosomal recessive cerebellar ataxias. Their classification, genetic features and pathophysiology].

INTRODUCTION AND DEVELOPMENT: Autosomal recessive cerebellar ataxias (ARCA) are a heterogeneous group of rare neurological disorders involving both central and peripheral nervous system, and in some case other systems and organs. They use to have early onset before the age of 20. Based on pathogenic mechanisms five main types may be distinguished: congenital (developmental disorder), mitochondrial ataxias, ataxias associated with metabolic disorders, ataxias with a DNA repair defect, and degenerative ataxia with unknown pathogenesis. The most frequent in Caucasian population are Friedreich ataxia and ataxia-telangiectasia. Other forms are much less common, and include abetaliproteinemia, ataxia with vitamin E deficiency (AVED), ataxia with oculomotor apraxia types 1 (AOA1) and 2 (AOA2), early onset cerebellar ataxia with retained reflexes, Charlevoix-Saguenay spastic ataxia, and Joubert syndrome. The prevalence of ARCA has been estimated to 7 in 100,000 inhabitants. These diseases are due to mutations in specific genes, some of which and its encoded proteins have been identified, such as FRDA (frataxin) in Friedreich ataxia, APTX (aprataxin) in AOA1, alphaTTP (alpha-tocopherol transfer protein) in AVED, and STX (senataxin) in AOA2. Due to autosomal recessive inheritance, previous familial history of affected individuals unlikely. CONCLUSIONS: Most of these cerebellar ataxias have no specific treatment with exception of the ataxia associated with deficiency coenzyme Q10 and abetalipoproteinemia. Clinical diagnosis must be confirmed by ancillary tests such as neuroimaging (magnetic resonance, scanning), electrophysiological examination, and mutation analysis when the causative gene has been identified. Correct clinical and genetic diagnosis is important for appropriate prognosis and genetic counseling and, in some instances, pharmacological treatment.

Age of Onset↗