Abstract
Huntington's disease (HD) is an autosomal dominant neurodegenerative disorder that affects the striatum most severely. However, except for juvenile forms, relative preservation of the cerebellum has been reported. The objective of the present study was to perform MRI measurements of caudate, putamen, cerebral, and cerebellar volumes and correlate these findings with the length of the CAG repeat and clinical parameters. We evaluated 50 consecutive patients with HD using MRI volumetric measurements and compared them to normal controls. Age at onset of the disease ranged from 4 to 73 years (mean: 43.1 years). The length of the CAG repeat ranged from 40 to 69 (mean: 47.2 CAG). HD patients presented marked atrophy of the caudate and putamen, as well as reduced cerebellar and cerebral volumes. There was a significant correlation between age at onset of HD and length of the CAG repeat, as well as clinical disability and age at onset. The degree of basal ganglia atrophy correlated with the length of the CAG repeat. There was no correlation between cerebellar or cerebral volume and length of the CAG repeat. However, there was a tendency to a positive correlation between duration of disease and cerebellar atrophy. While there was a negative correlation of length of the CAG repeat with age at disease onset and with striatal degeneration, its influence on extrastriatal atrophy, including the cerebellum, was not clear. Extrastriatal atrophy occurs later in HD and may be related to disease duration.
Highlights
Huntington’s disease (HD) is a dominantly inherited neurodegenerative disorder that usually manifests in adulthood, resulting in familial adult onset chorea and subcortical dementia [1]
There was a marked reduction of caudate and putamen nuclei and of cerebral and cerebellar volume in HD patients, with a significant difference from controls (P < 0.0001; Figure 2)
Since the original discovery that the HD phenotype results from an expanded CAG trinucleotide repeat within the IT15 gene located on chromosome 4 [1,2], several hypotheses have been raised in an attempt to explain the mechanisms of expanded CAG repeats in the pathogenesis of HD
Summary
Huntington’s disease (HD) is a dominantly inherited neurodegenerative disorder that usually manifests in adulthood, resulting in familial adult onset chorea and subcortical dementia [1]. The exact function of huntingtin is unknown and there is no information about its threedimensional structure that suggests any putative function. The defect of this protein promotes neuronal apoptosis in various brain regions, especially the basal ganglia, and the caudate nucleus in particular. The cerebellum is spared in the adult form, and in the great majority of patients the cerebellar changes have been reported to be discrete [5,6]
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