Background: Loss or reversal of the normal asymmetry of the planum temporale (PT) has been reported in schicophrenia, and may be due to aberations in the gene(s) controlling the development of brain asymmetries. We tested this hypothesis in a sample of schizophrenics and their relatives from families multiply affected with the disorder.
Method: We compared 32 schizophrenics and 55 of their non-schizophrenic first-degree relatives with 39 matched community controls. Volumetric measurements of the cortical volume beneath the PT were obtained using the Cavalieri method from three-dimensionally reconstructed magnetic resonance imaging images.
Results: PT volume asymmetry coefficients from patients and their relatives did not differ significantly from those of the controls. Gender-specific analysis did not revealany differences.
Conclusions: Abnormalities in PT volume asymmetry are not present in familial schizophrenia, where genetic factors appear to predominate.