Phenotypic variation between parent-offspring trios and non-trios in genetic studies of schizophrenia.

Background: Phenotypic differences between parent-offspring trios and non-trios have been reported for various psychiatric disorders, and it has been suggested that this may make comparisons of case-control and family-based results for gene-disease association studies inappropriate.

Aims: To compare phenotypes between trios and non-trios with schizophrenia, and explore possible reasons for differences observed.

Method: Phenotypes were compared between trios (n=75) and non-trios (n=424) collected as part of a case-control study.

Polymorphisms in the MAOA, MAOB, and COMT genes and aggressive behavior in schizophrenia.

Some studies have reported associations between COMT and MAO genotypes and aggression, though results have been inconsistent. We examined the relationship between Overt aggression scale (OAS) scores, and both MAOA and MAOB polymorphisms in a well-powered sample of 346 subjects with schizophrenia. We also examined COMT in a Stage II replication sample of 150 individuals, and combined these results with our previously reported (Stage I) findings for COMT.