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Updated: Aug 15, 2026
07:08
Fractionation for Resolution of Soluble and Insoluble Huntingtin Species
Published on: February 27, 2018
Trinucleotide repeat length and clinical progression in Huntington's disease
J Brandt1, F W Bylsma, R Gross
1Department of Psychiatry and Behavioral Sciences, Johns Hopkins University School of Medicine, Baltimore MD 21287-7218, USA.
Neurology
|February 1, 1996
Summary
Longer CAG repeat lengths in Huntington's disease patients predict faster progression. This finding highlights the CAG repeat expansion as a key factor in disease severity and decline.
Area of Science:
- Genetics
- Neuroscience
- Neurology
Background:
- Huntington's disease (HD) is a progressive neurodegenerative disorder.
- The disease is caused by an expansion of CAG trinucleotide repeats in the huntingtin gene (HTT).
- The relationship between CAG repeat length and disease progression in HD requires further investigation.
Purpose of the Study:
- To investigate the association between the length of the CAG trinucleotide repeat expansion in the IT-15 gene and the clinical progression of Huntington's disease.
- To determine if CAG repeat length predicts the rate of neurologic and cognitive decline in HD patients.
Main Methods:
- A longitudinal study of 46 patients with mild to moderate Huntington's disease over a 2-year period.
- Patients were categorized into short (37-46 repeats) and long (> or = 47 repeats) CAG repeat mutation groups.
- Clinical assessments included neurologic and cognitive function evaluations at baseline and follow-up.
Main Results:
- Patients with longer CAG repeat lengths exhibited an earlier age of onset and were younger at the initial visit.
- Despite similar baseline neurologic and cognitive function, the long-repeat group showed significantly greater decline over 2 years.
- CAG repeat length strongly correlated with age at onset (r = -0.72) and predicted both neurologic and cognitive decline.
Conclusions:
- CAG repeat length is a significant determinant of Huntington's disease progression rate.
- Longer CAG repeat expansions are associated with more rapid neurologic and cognitive deterioration.
- Further research is needed to elucidate the mechanisms underlying the more severe disease process in longer repeat expansions.
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