Nineteen CAG repeats of the SCA6 gene in a Japanese patient presenting with ataxia

Katayama, Takayuki; Ogura, Yukie; Aizawa, Hitoshi; Kuroda, Hikaru; Suzuki, Yasuhiro; Kuroda, Kenji; Kikuchi, Kenjiro

doi:10.1007/s004150070117

Cited by 15 publications

(8 citation statements)

References 11 publications

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“…The normal allele size of the polymorphic CAG repeat ranges from 4-18 units (Zhuchenko et al, 1997;Shizuka et al, 1998a, b), while that of expanded alleles is from 20-30 repeats (Jodice et al, 1997;Matsuyama et al, 1997;Shizuka, et al, 1998a, b;Katayama et al, 2000). Data on the intermediate allele with 19 repeats are contradictory.…”

Section: Gene Mutation and Inheritancementioning

confidence: 99%

Spinocerebellar ataxia type 6 and episodic ataxia type 2: differences and similarities between two allelic disorders

Mantuano

Veneziano²,

Jodice³

et al. 2003

Cytogenet Genome Res

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Spinocerebellar ataxia type 6 (SCA6) is one of three allelic disorders caused by mutations of CACNA1A gene, coding for the pore-forming subunit of calcium channel type P/Q. SCA6 is associated with small expansions of a CAG repeat at the 3′ end of the gene, while point mutations are responsible for its two allelic disorders (Episodic Ataxia type 2 and Familial Hemiplegic Migraine). Genetic, clinical, pathological and pathophysiological data of SCA6 patients are reviewed and compared to those of other SCAs with expanded CAG repeats as well as to those of its allelic channelopathies, with particular reference to Episodic Ataxia type 2. Overall SCA6 appears to share features with both types of disorders, and the question as to whether it belongs to polyglutamine disorders or to channelopathies remains unanswered at present.

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Section: Gene Mutation and Inheritancementioning

confidence: 99%

Spinocerebellar ataxia type 6 and episodic ataxia type 2: differences and similarities between two allelic disorders

Mantuano

Veneziano²,

Jodice³

et al. 2003

Cytogenet Genome Res

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show abstract

“…The reason for this analysis is that the effect of normal allele may not be neglected because of the shortness of the CAG repeat length even in the expanded allele. Additionally, both SCA6 patients and normal individuals were reported to have the intermediate CAG repeats number of 19-20 (Ishikawa et al 1997;Katayama et al 2000;Mariotti et al 2001), and these findings cannot be explained only by the effect of the expanded allele.…”

Section: Genetic Testing For Sca6mentioning

confidence: 99%

“…The 19 CAG repeat-units have been reported as the lower limit of expansion causing SCA6 (Katayama et al 2000;Mariotti et al 2001), although this repeat has been observed in normal alleles, including ours (Ishikawa et al 1997). When the age of onset versus repeat length in the expanded allele is applied, the analysis of age of onset with the total number of CAG repeats in both chromosomes may be important.…”

Section: Genetic Aspectsmentioning

confidence: 99%

“…When the age of onset versus repeat length in the expanded allele is applied, the analysis of age of onset with the total number of CAG repeats in both chromosomes may be important. For instance, the lower limit of expansion causing SCA6 became obscure: the 19 repeat-units in a 1A (P/Q type) subunit gene was previously reported ''normal'' (Ishikawa et al 1997), while patients with 19 repeats showing progressive ataxia have recently been reported (Katayama et al 2000;Mariotti et al 2001). This difference may also be explained by the difference in the total repeat number.…”

Section: Genetic Aspectsmentioning

confidence: 99%

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A clinical and genetic study in a large cohort of patients with spinocerebellar ataxia type 6

et al. 2004

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In order to clarify the clinical and genetic features of SCA6, we retrospectively analyzed 140 patients. We observed an inverse correlation between the age of onset and the length of the expanded allele, and also between the age of onset and the sum of CAG repeats in the normal and the expanded alleles. The ages of onset of four homozygous patients correlated better with the sum of CAG repeats in both alleles rather than with the expanded allele calculated from heterozygous SCA6 subjects. Clinically, unsteadiness of gait was the main initial symptom, followed by vertigo and oscillopsia, and cerebellar signs were detected in nearly 100% of the patients. In contrast, extracerebellar signs were relatively mild and infrequent. The results of neuro-otological examination performed in 22 patients suggested the purely cerebellar abnormalities of ocular movements in nature. There was a close relationship between downbeat positioning nystagmus (DPN) and positioning vertigo, which became more common in the later stage. We conclude that total number of CAG repeat-units in both alleles is a good parameter for assessment of age of onset in SCA6 including homozygous patients. In addition, clinical and neuro-otological examinations suggested that SCA6 is a disease with predominantly cerebellar dysfunction.

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“…However, the extent of polymorphism differs between loci (Table 1). In some cases, there is an overlap between normal and expanded alleles whereas in some there is a transition range between normal and expanded (mutated) alleles, being either unstable normal alleles or premutation alleles [Hellenbroich et al, 2004;Katayama et al, 2000;Matsuura et al, 2006;Nardacchione et al, 1999;Ranum et al, 1999;Rolfs et al, 2003;Zuhlke et al, 2002). The pathological threshold varies depending on whether the repeat is coding or noncoding.…”

Section: Introductionmentioning

confidence: 99%

SCA-LSVD: A repeat-oriented locus-specific variation database for genotype to phenotype correlations in spinocerebellar ataxias

et al. 2009

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Nineteen CAG repeats of the SCA6 gene in a Japanese patient presenting with ataxia

Cited by 15 publications

References 11 publications

Spinocerebellar ataxia type 6 and episodic ataxia type 2: differences and similarities between two allelic disorders

Spinocerebellar ataxia type 6 and episodic ataxia type 2: differences and similarities between two allelic disorders

A clinical and genetic study in a large cohort of patients with spinocerebellar ataxia type 6

SCA-LSVD: A repeat-oriented locus-specific variation database for genotype to phenotype correlations in spinocerebellar ataxias

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