Genome wide linkage anlaysis supports the presence of two separate susceptibility loci on chromosome 1q32 for biopolar disorder and 1q21-22.3 for schizophrenia

Hovatta et al 1999 reported linkage to schizophrenia with markers on chromosome 1q22.2 with maximum lods of 3.73 and 3.82 using the markers D1S2141 and D1S2891. A second, separate genome scan of affected sib pairs in Finland (Ekelund et al. 1997) also implicated this region on chromosome 1. A locus on the long arm of chromosome 1q21-22.2 has been confirmed in a genome scan of schizophrenia by us (Gurling et al 1999) with a five point multipoint lod of 3.2 with the markers D1S194-D1S196 -D1S2815-D1S191. We have employed exactly the same markers in a genome scan of bipolar and related unipolar disorders (Curtis et al 1999) and have also obtained a positive three point multipoint lod score of 2.47 (p<0.005) with the markers D1S229 and D1S251 on chromosome 1q34. Detera-Wadleigh et al (1999) also implicated this region on chromosome 1 in bipolar disorder with a lod of 2.67 (P<0.00022) at 1q32. The two positive regions implicated in schizophrenia and bipolar disorder in our own genome scans do not overlap and do not provide support for a common genetic etiology for schizophrenia and bipolar disorder on chromosome 1q. References: Curtis, D. et al.(1999) Molecular Psychiatry 4, 141. Gurling, H.M.D. et al. (1999) Molecular Psychiatry 4, S4 (1999). Hovatta, I. et al. Am. J. Hum. Genet. 65, 1114-1124 (1999). DeteraWadleigh, SD et al (1999) PNAS, 96, 5604-5609. Acknowledgements: The research was funded by Medical Research Council special project grant G9623693N and by research lectureships from the Priory Hospital London, The European Science Foundation, Schizophrenia A National Emergency (SANE), the Joseph Levy Charitable Foundation, the Wellcome Trust, the Health Service of Iceland. We thank the organizing committees of the ESF Network of the Molecular Neurobiology of Mental Illness and the scientific and technical staff of Genethon in Paris for genotyping.