ORIGINAL ARTICLESGenetic linkage study for bipolar disorders on chromosomes 17 and 18 in families with a high expression of mental illness from the Balearic IslandsTomàs, Carmena; Cañellas, Franciscac; Rodríguez, Virginiaa; Picornell, Antòniaa; Lafau, Oriolc; Nadal, Marcosc; Roca, Miquelb; Serrano, M. Jesúsb; Castro, José A.a; Ramon, M. MisericòrdiaaAuthor Information aLaboratory of Genetics, Department of Biology, University Institute of Health Sciences (IUNICS) bJuan March Hospital, and IUNICS, University of Balearic Islands cService of Psychiatry, Son Dureta Hospital, Palma de Mallorca, Spain Correspondence and requests for reprints to Dr M.M. Ramon, Laboratori de Genètica, Departament de Biologia, Facultat de Ciències, Universitat de les Illes Balears, 07122 Palma de Mallorca (Balears), Spain Tel: +34 971 173152; fax: +34 971 173184; e-mail: firstname.lastname@example.org Sponsorship: This work was supported by grant FIS99-0440 from the Ministerio de Sanidad y Consumo (Spain). Received 10 August 2005 Accepted 25 February 2006 Psychiatric Genetics: August 2006 - Volume 16 - Issue 4 - p 145-151 doi: 10.1097/01.ypg.0000218614.42762.b0 Buy Metrics Abstract Genetically, bipolar disorder is a complex genetic illness, in which both genes and environmental factors play an important role in pathogenesis. Linkage studies have reported suggestive evidence for genomic regions, especially on chromosome 18, but in most cases they have been inconclusive. A total of 12 pedigrees, from the islands of Majorca and Minorca (Balearic Archipelago), with a high expression of mental illness, have been studied. A scan of 29 polymorphic short tandem repeat markers was performed, spanning chromosomes 17 and 18 for bipolar and other affective disorder susceptibility loci. Narrow (only bipolar I disorder) and broad (bipolar plus other affective disorders) diagnosis criteria were employed. The loci D18S63, D18S452, D18S53, D18S61, D18S1161 and D17S831 showed LOD score values of less than −2. Thus, the positive linkage found by other authors on the regions 18p11.2 and 18p11.3 has not been reproduced in the families studied. The data obtained in chromosome 17 suggested two possible regions that could contain a bipolar disorder susceptibility gene: 17q11 (D17S1857, D17S798) and especially 17q24-qter (D17S949, D17S928). The maximum significant linkage was to D17S949 (17q24), following a recessive mode of inheritance. We have also found a positive LOD score value for D18S478 marker located in the region 18q12. © 2006 Lippincott Williams & Wilkins, Inc.