Document Detail

Expanded CAG repeats in Swedish spinocerebellar ataxia type 7 (SCA7) patients: effect of CAG repeat length on the clinical manifestation.
MedLine Citation:
PMID:  9425223     Owner:  NLM     Status:  MEDLINE    
Spinocerebellar ataxia 7 (SCA7) is a neurodegenerative disorder characterized by degeneration of the cerebellum, brainstem and retina. The gene responsible for SCA7, located on chromosome 3p, recently was cloned and shown to contain a CAG repeat in the coding region of the gene, that is expanded in SCA7 patients of French origin. We examined the SCA7 repeat region in four Swedish SCA7 families as well as in 57 healthy controls. All Swedish SCA7 patients exhibited expanded CAG repeats with a strong negative correlation between repeat size and age of onset. The repeat length in SCA7 patients ranged from 40 to >200 repeats. The largest expansion was observed in a juvenile case with an age of onset of 3 months, and represents the longest polyglutamine stretch ever reported. In patients with 59 repeats or more, visual impairment was the most common initial symptom observed, while ataxia predominates in patients with <59 repeats. Two of the Swedish SCA7 families analysed in this study were shown to be related genealogically. The other two SCA7 families could not be traced back to a common ancestor. All four families shared the same allele on the disease chromosome at a locus closely linked to SCA7, suggesting the possibility of a founder effect in the Swedish population.
J Johansson; L Forsgren; O Sandgren; A Brice; G Holmgren; M Holmberg
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Publication Detail:
Type:  Comparative Study; Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  Human molecular genetics     Volume:  7     ISSN:  0964-6906     ISO Abbreviation:  Hum. Mol. Genet.     Publication Date:  1998 Feb 
Date Detail:
Created Date:  1998-03-17     Completed Date:  1998-03-17     Revised Date:  2006-11-15    
Medline Journal Info:
Nlm Unique ID:  9208958     Medline TA:  Hum Mol Genet     Country:  ENGLAND    
Other Details:
Languages:  eng     Pagination:  171-6     Citation Subset:  IM    
Department of Clinical Genetics, University Hospital of Umeâ, S-90185 Umeâ, Sweden.
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MeSH Terms
Age of Onset
Child, Preschool
Chromosomes, Human, Pair 3 / genetics*
Haplotypes / genetics
Macular Degeneration / classification,  epidemiology,  genetics*
Middle Aged
Severity of Illness Index
Spinocerebellar Degenerations / classification,  epidemiology,  genetics*
Sweden / epidemiology
Trinucleotide Repeats*

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine

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