title: Relationship between CAG repeat length and brain volume in premanifest and early Huntington's disease.
abstract: Huntington's disease (HD) is caused by an expanded CAG repeat on the gene encoding for the protein huntingtin. There are conflicting findings about the extent to which repeat length predicts signs of the disease or severity of disease progression in adults. This study examined the relationship between CAG repeat length and brain volume in a large cohort of pre- and post-motor onset HD gene carriers, using voxel-based morphometry (VBM), an approach which allowed us to investigate the whole brain without defining a priori regions of interest. We also used VBM to examine group differences between 20 controls, 21 premanifest, and 40 early HD subjects. In the 61 mutation-positive subjects higher CAG repeat length was significantly associated with reduced volume of the body of the caudate nucleus bilaterally, left putamen, right insula, right parahippocampal gyrus, right anterior cingulate, and right occipital lobe, after correcting for age. The group contrasts showed significant reduction in grey matter volume in the early HD group relative to controls in widespread cortical as well as subcortical areas but there was no evidence of difference between controls and premanifest subjects. Overall we have demonstrated that increased CAG repeat length is associated with atrophy in extra-striatal as well as striatal regions, which has implications for the monitoring of disease-modifying therapies in the condition.
authors.affiliation: Dementia Research Centre, Institute of Neurology, University College, London, UK. shenley@drc.ion.ucl.ac.uk
authors.forename: Susie M D
authors.initials: SM
authors.lastname: Henley
authors.forename: Edward J
authors.initials: EJ
authors.lastname: Wild
authors.forename: Nicola Z
authors.initials: NZ
authors.lastname: Hobbs
authors.forename: Rachael I
authors.initials: RI
authors.lastname: Scahill
authors.forename: Gerard R
authors.initials: GR
authors.lastname: Ridgway
authors.forename: David G
authors.initials: DG
authors.lastname: Macmanus
authors.forename: Roger A
authors.initials: RA
authors.lastname: Barker
authors.forename: Nick C
authors.initials: NC
authors.lastname: Fox
authors.forename: Sarah J
authors.initials: SJ
authors.lastname: Tabrizi
mesh_terms: D000328:Adult; D000375:Aging / Q000473:pathology; D001284:Atrophy / Q000235:genetics / Q000378:metabolism / Q000473:pathology*; D001921:Brain / Q000378:metabolism / Q000473:pathology* / Q000503:physiopathology; D015331:Cohort Studies; D004252:DNA Mutational Analysis; D018450:Disease Progression; D005260:Female; D005819:Genetic Markers / Q000235:genetics; D020022:Genetic Predisposition to Disease / Q000235:genetics*; D005820:Genetic Testing; D005838:Genotype; D006801:Humans; D000071058:Huntingtin Protein; D006816:Huntington Disease / Q000235:genetics* / Q000473:pathology* / Q000503:physiopathology; D007091:Image Processing, Computer-Assisted; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D009419:Nerve Tissue Proteins / Q000235:genetics; D009687:Nuclear Proteins / Q000235:genetics; D019680:Trinucleotide Repeat Expansion / Q000235:genetics*
chemical_list: D005819:Genetic Markers; C086055:HTT protein, human; D000071058:Huntingtin Protein; D009419:Nerve Tissue Proteins; D009687:Nuclear Proteins