Detection of polymorphic triplet repeats in the genomes of patients suffering from bipolar affective disorder

Evidence for the operation of expanded trinucleotide repeats in the pathogenesis of bipolar affected disorder has recently been found at the molecular genetic level. For the screening of these repeat motifs in genomes of patients with bipolar affective disorder, we established a modified PCR-based fingerprinting technique, called triplet repeat enhanced arbitrarily primed PCR (TREAP-PCR). Using this approach, 40 patients suffering from bipolar affective disorder (ICD10: F31) and 15 healthy controls were investigated. Interindividual polymorphisms generated by TREAP-PCR seemed to depend on the type of triplet. Using CCG triplet primers, polymorphisms could be observed more often in the genomes of patients compared with controls, whereas no significant differences could be found using primers of the CAG or AAT type. These data might indicate the existence of subgroups of manic-depressive patients based on molecular genetic differences.