Inhibitory neurophysiological deficit as a phenotype for genetic investigation of schizophrenia

Many investigators have proposed that biological endophenotypes might facil itate the genetic analysis of schizophrenia. A deficit in the inhibition of the P50 evoked response to repeated auditory stimuli has been characterize d as a neurobiological deficit in schizophrenia. This deficit is linked to a candidate gene locus, the locus of the alpha 7-nicotinic cholinergic rece ptor subunit gene on chromosome 15q14. Supportive evidence has been found b y other investigators, including: 1) linkage of schizophrenia to the same l ocus, 2) linkage of bipolar disorder to the locus; and 3) replication of th e existence of this neurobiological deficit and its relation to broader neu ropsychological deficits in schizophrenia. It is certain that there are man y genetic factors in schizophrenia and bipolar disorder; what is needed is a complete and precise description of the contribution of each individual f actor to the pathophysiology of these illnesses. (C) 2000 Wiley-Liss, Inc.