A weakassociation between TH andDRD2 genesandbipolar affective disorder ina Spanish sample

Genetic factors playanimportant rolein theaetiology ofbipolar affective disorder (BP).Sofar, results oflinkage studies have been largely disappointing. We have searched fora possible association betweenpolymorphic DNA markersoftwo candidate genes(tyrosine hydroxylase, TH;dopamineD2 receptor gene,DRD2) andBPinapopulation fromcentral Spain. Our results areconsistent withtheexistence ofaweakassociation between these twogenesandBP,insuchawaythatTH andDRD2 couldbeconsidered asminor genescontributing tosusceptibility. (JMed Genet1995;32:131-134)