AN ASSOCIATION STUDY BETWEEN SCHIZOPHRENIA AND THE DOPAMINE-RECEPTOR GENES DRD3 AND DRD4 USING HAPLOTYPE RELATIVE RISK

Our work investigates the relationship between genetic factors and sch izophrenia, seeking to identify a gene or genes associated with the cl inical form of the disease in a group of Italian patients. In pursuit of the 'dopaminergic hypothesis' of schizophrenia, we explored a possi ble etiologic role of two dopamine receptor genes, DRD3 and DRD4, that have been repeatedly suggested as factors in the pathophysiology of t he disease. We typed DNA polymorphisms in each of the genes that code for variation in the amino acid sequence of the receptor protein. An i nnovative design using parental chromosomes as controls - the 'haploty pe relative risk' strategy - represents a significant improvement over previous association studies in psychiatric genetics. Our results sug gest that, at least in our well-defined population the candidate genes DRD3 and DRD4 do not appear to play a major role in the genetic etiol ogy of schizophrenia.