NO ASSOCIATION BETWEEN CHROMOSOME-18 MARKERS AND LITHIUM-RESPONSIVE AFFECTIVE-DISORDERS

An allelic association study of excellent responders to lithium was co nducted with a candidate gene (G(olf),ln a G-protein receptor gene) an d five other chromosome-18p markers. G(olf) is of special interest bec ause it maps to a region of chromosome 18 where two independent groups (Berrettini et al., 1994; Stine et al., 1995) have found linkage to b ipolar disorder. It has been proposed that G proteins are involved in the pathogenesis of bipolar disorder, and lithium, an effective prophy lactic agent, is known to impair G-protein activation. To reduce heter ogeneity - a common obstacle to genetic investigation - only patients who showed excellent response to lithium prophylaxis were studied. Fif ty-five genetically unrelated excellent responders to lithium prophyla xis were compared with 94 normal subjects of similar ethnic background . The groups did not differ in either allele or genotype frequency for the tested markers, The data do not support the hypothesis that the t ested loci confer a major susceptibility for affective disorders.