OBJECTIVETo explore the role of genetic factors in the brain structural variation by using magnetic resonance imaging scan in schizophrenic patients and their unaffected siblings, and to provide experimental evidence for identifying endophenotype of schizophrenia.

METHODSThe optimized voxel-based morphometry (OVBM) was used to process the brain magnetic resonance images in 15 first episode drug-naive schizophrenic patients, 19 unaffected siblings of the patients and 38 normal control subjects. The data were analyzed by using general linear model.

RESULTSCompared to the normal control subjects, significant decreases of gray matter was observed in first episode drug-naive schizophrenia in bilateral temporal lobe, bilateral occipital lobe, left insula, left frontal lobe superior frontal gyrus and right lentiform nucleus medial globus pallidus. Significant increases of gray matter in bilateral parietal lobe, bilateral limbic lobe cingulate gyrus in patients group while compared to controls were also found. In unaffected siblings, significant decreases of gray matter was observed in the right temporal lobe, bilateral occipital lobe, left insula, and left frontal lobe precentral gyrus, and significant increases of gray matter were found in left parietal lobe and bilateral cerebellum posterior lobe. Increased gray matter in left parietal lobe precuneus was found in first episode drug-naive schizophrenia when compared with their unaffected siblings.

CONCLUSIONThere were similar brain structure abnormalities between the first episode drug-naive schizophrenia and their unaffected siblings. Genetic factor may play important role in brain structural abnormality in schizophrenia, which suggested that the brain structural change might be a genetic endophenotype of schizophrenia.