Report of the Chromosome 18 Workshop

At the first chromosome 18 workshop held at the 1997 World Congress on Psyc hiatric Genetics (WCPG) in Santa Fe, NM, several studies were presented tha t suggested the presence of a bipolar disorder (BP) as well as a schizophre nia (SZ) susceptibility locus on chromosome 18. Although the fact that seve ral independent studies all pointed to a susceptibility locus (or loci) on chromosome 18, the observation that these studies identified nonoverlapping candidate regions was disappointing at least from the viewpoint of molecul ar genetics aiming at cloning the respective gene(s), Together, the data su ggested four possible regions of considerable size that contained a suscept ibility gene. At the 1998 WCPG chromosome 18 workshop in Bonn, Germany, les s data were submitted and with the exception of a few studies, most data we re nonsupportive or negative. Although some refinements were made to the pr evious candidate loci, overall the picture has not changed in that we are s till confronted with the same four potential loci on chromosome 18 for BP a nd/or SZ, i.e., 18p11.2 and 18q12.1-q12.3 for BP and SZ, and 18q21-q122 and 18q23-qter for BP. So far, no other psychiatric phenotypes show evidence f or a susceptibility locus on chromosome 18, Am, J, Med. Genet, (Neuropsychi atr, Genet,) 88:263-270, 1999, (C) 1999 Wiley-Liss, Inc.