Am J Psychiatry 1997; 154:1146-1147
Copyright © 1997 by American Psychiatric Association
Exclusion of expansion of 50 CAG/CTG trinucleotide repeats in bipolar disorder
C Guy, T Bowen, JK Daniels, G Speight, P McKeon, L Mynett-Johnson, E Claffey, P McGuffin, MJ Owen, N Craddock and MC O'Donovan
Division of Psychological Medicine, University of Wales College of Medicine, Cardiff, Wales. wpcmod@Cardiff.ac.uk
OBJECTIVE: The purpose of this study was to identify the specific expanded
CAG/CTG trinucleotide repeat associated with bipolar disorder. METHOD: The
study employed an efficient multistage approach for using a genomic CAG/CTG
screening set. RESULTS: The authors found no evidence of expanded repeats
at 43 polymorphic autosomal loci and seven X chromosomal loci. Secondary
screening was pursued at the only locus that contained a large allele (37
repeats) in the primary screening. No association was found between allele
size and diagnostic status. CONCLUSIONS: It is highly unlikely that
expansions in repeat size at any of the 50 candidate trinucleotide repeat
loci examined are responsible for the association between expanded CAG/ CTG
repeats and bipolar disorder. However, although the authors prioritized the
repeats that were a priori most likely to be involved, the study does not
reject the more general hypothesis that expanded CAG/CTG repeats are
implicated in the pathogenesis of bipolar disorder.
