Spinocerebellar ataxia types 1, 2, 3, and 6: disease severity and nonataxia symptoms.
ABSTRACT To identify factors that determine disease severity and clinical phenotype of the most common spinocerebellar ataxias (SCAs), we studied 526 patients with SCA1, SCA2, SCA3. or SCA6.
To measure the severity of ataxia we used the Scale for the Assessment and Rating of Ataxia (SARA). In addition, nonataxia symptoms were assessed with the Inventory of Non-Ataxia Symptoms (INAS). The INAS count denotes the number of nonataxia symptoms in each patient.
An analysis of covariance with SARA score as dependent variable and repeat lengths of the expanded and normal allele, age at onset, and disease duration as independent variables led to multivariate models that explained 60.4% of the SARA score variance in SCA1, 45.4% in SCA2, 46.8% in SCA3, and 33.7% in SCA6. In SCA1, SCA2, and SCA3, SARA was mainly determined by repeat length of the expanded allele, age at onset, and disease duration. The only factors determining the SARA score in SCA6 were age at onset and disease duration. The INAS count was 5.0 +/- 2.3 in SCA1, 4.6 +/- 2.2 in SCA2, 5.2 +/- 2.5 in SCA3, and 2.0 +/- 1.7 in SCA6. In SCA1, SCA2, and SCA3, SARA score and disease duration were the strongest predictors of the INAS count. In SCA6, only age at onset and disease duration had an effect on the INAS count.
Our study suggests that spinocerebellar ataxia (SCA) 1, SCA2, and SCA3 share a number of common biologic properties, whereas SCA6 is distinct in that its phenotype is more determined by age than by disease-related factors.
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ABSTRACT: Spinocerebellar ataxia type 7 (SCA7) is a genetic disorder characterized by degeneration of the cerebellum, brainstem, and retina that is caused by abnormal expansion of a CAG repeat located in the ATXN7 gene encoding sequence on chromosome 3p21.1. Although SCA7 is an uncommon autosomal dominant ataxia, we previously found increased prevalence of the disease in a Southeastern Mexican population. In this study, we described to our knowledge for the first time a marriage of consanguineous SCA7 mutation carriers and their offspring effect. We characterized a severely affected infantile-onset female patient whose parents and two siblings exhibited no symptoms of the disease at time of diagnosis. A comprehensive clinical analysis of the proband showed a progressive cerebellar syndrome, including gait ataxia, movement disorders, and saccadic movements, as well as hyperreflexia, visual deterioration, urinary and cardiovascular dysfunction, and impaired nerve conduction. The SCA7 mutation was detected in the proband patient. Subsequently, genetic examination using four ATXN7 gene-linked markers (three centromeric microsatellite markers [D3S1228, D3S1287, and D3S3635] and an intragenic Single Nucleotide Polymorphism [SNP-3145G/A]) revealed that the proband descends from a couple of consanguineous SCA7 mutation carriers. Genotyping analysis demonstrated that all offspring inherited only one mutant allele, and that the severe infantile-onset phenotype is caused by germinal expansion (from 37 to 72 CAG repeats) of the paternal mutant allele. Interestingly, the couple also referred a miscarriage. Finally, we found no CAA interruptions in the ATXN7 gene CAG repeats tract in this family, which might explain, at least in part, the triplet instability in the proband.International Journal of Clinical and Experimental Medicine 01/2014; 7(12):5896-903. · 1.42 Impact Factor
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ABSTRACT: In this article, we describe three patients with different spinocerebellar ataxia (SCA) subtypes presenting with unusual movement disorders predominantly characterized by choreoathetosis, which, together with their autosomal dominant pattern of inheritance, resembled the Huntington-like syndromes. From a large SCA cohort, we have observed chorea in 1/35 SCA2, 1/112 SCA3/MJD, and 1/30 SCA7 patients. Twenty-eight patients with SCA1, 11 patients with SCA6, and 3 patients with SCA10 were also evaluated, and none of them presented chorea. We provide a brief report of the three cases, with a video demonstrating chorea. Although a debate regarding the frequency of chorea in SCA patients is a fact, its occurrence, together with the autosomal dominant pattern of inheritance, clearly imposes SCA in the differentials of Huntington-like syndromes. There is some debate about what to include in a list of Huntington-like disorders, with several review articles about Huntington-like syndromes not including SCA in the differential diagnosis, except for SCA17. We believe that SCAs-at least SCA1, SCA2, SCA3/MJD, SCA7 and DRPLA-should be thought in the diagnostic workout of at least the atypical cases, such as those presented in this report. Copyright © 2014 Elsevier B.V. All rights reserved.Journal of the Neurological Sciences 10/2014; 347(1-2):356-358. DOI:10.1016/j.jns.2014.09.050 · 2.26 Impact Factor
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ABSTRACT: Inherited spinocerebellar ataxias (SCAs) are known to be genetically and clinically heterogeneous. Whether severity and survival are variable, however, is not known. We, therefore, studied survival and severity in 446 cases and 509 relatives with known mutations. Survival was 68 years [95% CI: 65–70] in 223 patients with polyglutamine expansions versus 80 years [73–84] in 23 with other mutations (P < 0.0001). Disability was also more severe in the former: at age 60, 30% were wheelchair users versus 3% with other SCAs (P < 0.001). This has implications for genetic counseling and the design of therapeutic trials.12/2014; 2(2). DOI:10.1002/acn3.156