A study of potential interactive genetic factors in Huntington's disease.
OBJECTIVE
To assess the role of genetic factors, other than the CAG repeat length, on the development of Huntington's disease (HD) in an isolated Caucasian population in the south-west of Western Australia.


METHODS
114 patients with symptomatic HD according to the Unified HD Rating Scale research criteria were examined along with 51 control patients. The length of the CAG repeat sequence in the IT15 gene and the adjacent CCG and Delta2642 polymorphisms were determined by polymerase chain reaction along with common genotypes of the angiotensin-converting enzyme (ACE) and apolipoprotein E (APOE) genes.


RESULTS
The CAG expansion was associated with age of onset and the development of neurological dysfunction. We found no effect of the expanded CCG allele on age of onset, neurological dysfunction or the size of the CAG expansion. We observed a twofold increase in the Delta2642 polymorphism and the risk of developing symptomatic HD which was not significant (OR 2.06; 95% CI 0.60-7.07). The presence of an APOE epsilon4 allele was associated with an increased risk of HD which was not significant either (OR 1.04-1.73; 95% CI 0.10-10.68). ACE genotypes showed no association with risk factors for the disease.


CONCLUSIONS
In our study of a geographically isolated Caucasian HD population in the south-west of Western Australia we have not observed that the expanded CCG allele, the Delta2642 polymorphism, the APOE epsilon4 allele and ACE genotypes are associated with an increased risk for the development of symptomatic HD.
Panegyres
Peter K
PK
Neurosciences Unit, Department of Health, University of Western Australia, Perth, Australia. macfarlane4@optusnet.com.au
Beilby
John
J
Bulsara
Max
M
Toufexis
Katina
K
Wong
Cathy
C
D053327:Apolipoprotein E4; D001057:Apolipoproteins E / Q000235:genetics; D006801:Humans; D006816:Huntington Disease / Q000235:genetics*; D016017:Odds Ratio; D007703:Peptidyl-Dipeptidase A / Q000235:genetics; D016133:Polymerase Chain Reaction; D011110:Polymorphism, Genetic; D012016:Reference Values; D017384:Sequence Deletion; D018911:Trinucleotide Repeats
D053327:Apolipoprotein E4; D001057:Apolipoproteins E; D007703:Peptidyl-Dipeptidase A