An integrated map of chromosome 18 CAG trinucleotide repeat loci

Expansions of trinucleotide CAG repeats have been demonstrated in at least eight neurodegenerative disorders, and suggested to occur in several others , including bipolar disorder and schizophrenia. Chromosome 18 loci have bee n implicated in bipolar disorder pedigrees by linkage analysis. To address this putative link between chromosome 18 CAG trinucleotide repeats and neur opsychiatric illness, we have screened a chromosome 18 cosmid Library (LL18 NCO2" AD") and identified 14 novel candidate loci. Characterisation of thes e loci involved repeat Bank sequencing, estimation of polymorphism Frequenc y and mapping using FISH as well as radiation hybrid panels. These mapped t rinucleotide loci will be useful in the investigation of chromosome 18 in n eurodegenerative or psychiatric conditions, and will serve to integrate phy sical and radiation hybrid maps of chromosome 18.