CAG repeats of CTG18.1 and KCNN3 in Korean patients with bipolar affectivedisorder

Background: Trinucleotide repetition combined with variable penetrance of e xpression could be responsible for the complex transmission pattern observe d in bipolar affective disorder (BPAD). The purpose of this study was to in vestigate the association of excess longer allele of KCNN3 and CTG18.1 in t he patients with BPAD. Methods: CAG/CTG repeat distribution in KCNN3, CTG 1 8.1 and ERDA1 was examined and the copy number of ligation product in repea t expansion detection (RED) was measured in Korean bipolar patients in comp arison to ethnically matched healthy controls. Results: No significant diff erence was found in the allele distribution of those repeats between bipola r patients and controls. Ligation product size in RED was not increased in bipolar patients. However, the copy number of ligation product in RED was h ighly correlated with CAG/CTG copies of ERDA1 (P = 0.0001), partly with CTG 18.1 (P = 0.04), but not with KCNN3. Conclusions: A longer CAG repeat alle les of KCNN3 or CTG 18.1 may not be a risk factor for BPAD in Korean popula tion and the copy number of ligation product in RED in the patients with BP AD is influenced by the longer allele of CAG/CTG of ERDA1 or CTG 18.1. (C) 2001 Elsevier Science BY All rights reserved.