No evidence for a parent-of-origin effect detected in the pattern of inheritance of schizophrenia

Background: Schizophrenia is a complex genetic disorder with no clear patte rn of inheritance. Epigenetic modification of genes may thus play a role in its transmission, Methods: In our study, 439 families with at least two ill siblings with sch izophrenia (208 with unilineal transmission) were examined for evidence of a parent-of-origin effect (e.g., evidence of parental imprinting on the fam ilial transmission of schizophrenia), Results: No significant difference in the prevalence of maternal compared w ith paternal transmission was found lit addition, affected male subjects di d not differ from affected female subjects in the proportion of their offsp ring diagnosed with schizophrenia. Conclusions: Although the transmission of schizophrenia may be influenced b y epigenetic events, our study fails to find evidence that one epigenetic m echanism, a parent-of-origin imprinting effect, determines whether an indiv idual expresses the illness. (C) 2000 Society of Biological Psychiatry.