Search for bipolar disorder susceptibility loci: The application of a modified genome scan concentrating on gene-rich regions

Conducting genome wide screens for evidence of genetic linkage has become a well-established method for identifying regions of the human genome harbor ing susceptibility loci for complex disorders. For bipolar disorder, a numb er of such studies have been performed, and several regions of the genome h ave potentially been implicated in the disorder. The classic design for a g enome screen involves examining polymorphic genetic markers spaced at regul ar intervals throughout the genome, typically every 10 cM for evidence of l inkage. An alternative design, based on the observation that genes do not a ppear to be evenly distributed, was proposed, enabling the number of marker s examined in a genome wide screen to be reduced. This article describes th e application of such a modified screen to a collection of 48 Irish familie s with bipolar disorder, comprising a total of 82 affected sib-pairs. From the results obtained a number of regions are highlighted for further study. One of these regions (17q11.1-q12) coincides with the location of a candid ate gene, the serotonin transporter, whereas others concur with the finding s of published studies. (C) 2000 Wiley-Liss, Inc.