In search of a 22q11.2 deletion in schizophrenic patients with enlarged cava septi pellucidi (CSP) by using catechol-o-methyltransferase (COMT) immunohistochemistry and fluorescence in situ hybridization (FISH)

Aims: Patients suffering from velo-cardio-facial syndrome (VCFS) frequently develop schizophrenia. VCFS is associated with a deletion at chromosome 22q11.2, a region containing the COMT gene. A 22q11.2 deletion is very often accompanied with a high prevalence of a cavum septi pellucidi (CSP) in schizophrenia.

Materials and Methods: Eight schizophrenic patients with enlarged CSP (>100mm³) and three matched control cases were used to immunolocalize COMT on formalin fixed, paraffin embedded human brain sections. Fluorescence in situ hybridization (FISH) was applied to these paraffin human brain sections and the cell densities in the dorsolateral prefrontal cortex of the COMT immunostaining were measured to search for a potential 22q11.2 deletion in our sample of schizophrenic patients.

Results and Conclusions: Although no qualitative differences in the distribution and reaction intensity of COMT immunostaining were seen between control subjects and schizophrenic patients with enlarged CSP, these schizophrenic patients showed a higher cell density of glia cells in the dorsolateral prefrontal cortex in comparison to control subjects. The staining method in FISH works in paraffin embedded human brain sections, but requires further optimization to be more confident for the identification of potential gene microdeletions in paraffin sections.

Acknowledgements: This study was supported by NBL–3 (PP4) and the Stanley-Foundation.