Do COMT, BDNF and NRG1 polymorphisms influence P50 sensory gating in psychosis?

Background. Auditory P50 sensory gating deficits correlate with genetic risk for schizophrenia and constitute a plausible endophenotype for the disease. The well-supported role of catechol-O-methyltransferase (COMT), brain-derived neurotrophic factor (BDNF) and neuregulin 1 (NRG1) genes in neurodevelopment and cognition make a strong theoretical case for their influence on the P50 endophenotype. Method. The possible role of NRG1, COMT Val(158)Met and BDNF Val(66)Met gene polymorphisms on the P50 endophenotype was examined in a large sample consisting of psychotic patients, their unaffected relatives and unrelated healthy controls using linear regression analyses. Results. Although P50 deficits were present in patients and their unaffected relatives, there was no evidence for an association between NRG1, COMT Val(158)Met or BDNF Val(66)Met genotypes and the P50 endophenotype. Conclusions. The evidence from our large study suggests that any such association between P50 indices and NRG1, COMT Val(158)Met or BDNF Val(66)Met genotypes, if present, must be very subtle.