Patients presenting both types of ataxia did not show severe depletion in their nutritional status; however, those with SCA3 displayed greater weight loss and muscle mass reduction compared to the SCA10 group.
Here we investigated the ability of caffeine to alleviate behavioral deficits and cerebellar neuropathology in transgenic mice with a severe ataxia resulting from expression of a truncated fragment of polyglutamine-expanded ataxin-3 in Purkinje cells.
Spinocerebellar ataxia type 2 (SCA2) and type 3 (SCA3) are two common autosomal-dominant inherited ataxia syndromes, both of which are related to the unstable expansion of trinucleotide CAG repeats in the coding region of the related ATXN2 and ATXN3 genes, respectively.
We found that SCA3/MJD was the most common subtype in Han population in China, and the ratio of the pontine tegmentum and the posterior fossa area was negatively correlated with the number of cytosine-adenine-guanine (CAG) repeats; the disease duration was positively correlated with the International Cooperative Ataxia Rating Scale score; and the CAG repeats number of abnormal alleles was negatively correlated with the age of onset.
See Klockgether (doi:10.1093/awv253) for a scientific commentary on this article.The spinocerebellar ataxias types 2 (SCA2) and 3 (SCA3) are autosomal dominantly inherited cerebellar ataxias which are caused by CAG trinucleotide repeat expansions in the coding regions of the disease-specific genes.
Patients with SCA-ataxia (SCA2, SCA3) and Mito-ataxia (MELAS, MERRF, LHON, maternal inherited hearing impairment mtDNA A1555G mutation) were recruited in this study.
Machado-Joseph disease (MJD), the most common dominantly inherited ataxia worldwide, is caused by a polyglutamine (polyQ) expansion in the deubiquitinating (DUB) enzyme ataxin-3.
Spinocerebellar ataxia type 3/Machado-Joseph disease (SCA3/MJD) is an autosomal dominant neurodegenerative disease characterized by cerebellar ataxia associated with varying phenotypic variability.
The severity of ataxia was measured using the International Cooperative Ataxia Rating Scale (IARS) in 31 patients of SCA1 (mean+/-SD age: 35.1+/-12.6 years; age at onset (AAO): 29.9+/-10.7 years), 25 patients of SCA2 (age: 34.9+/-14.9 years; AAO: 29.7+/-14.0 years) and 15 patients of SCA3 (age: 40.9+/-8.6 years; AAO: 36.9+/-10.1).
In the ataxia group, we found (CAG)n above the range of the asymptomatic blood donors in SCA3 (21.74%) followed by SCA2 (5.22%), SCA7 (2.61%), SCA6 (0.87%), and no cases of SCA1.
Our study suggests that polyglutamine-expanded ataxin-3 causes cerebellar dysfunction and ataxia by disrupting the normal pattern of gene transcriptions.
Q71 transgenic mice expressing mutant ataxin-3 mjd1a above a critical level developed a phenotype similar to MJD including progressive postural instability, gait and limb ataxia, weight loss, premature death, neuronal intranuclear inclusions, and decreased tyrosine hydroxylase-positive neurons in the substantia nigra (determined by unbiased stereology).
SCA3 or Machado-Joseph disease (MJD) is the commonest dominant inherited ataxia disease, with pathological phenotypes apparent with a CAG triplet repeat length of 61-84.
We have previously shown in several pedigrees that SCA-2 and SCA-3 can cause both parkinsonism and typical Parkinson's disease in the absence of prominent ataxia; a finding which has been confirmed by others.
Machado-Joseph disease: cerebellar ataxia and autonomic dysfunction in a patient with the shortest known expanded allele (56 CAG repeat units) of the MJD1 gene.
To assess the frequency of the SCA1 and MJD trinucleotide repeat expansions among individuals diagnosed with ataxia we have collected DNA from individuals representing 311 families with adult-onset ataxia of unknown etiology and screened these samples for trinucleotide repeat expansions within the SCA1 and MJD genes.