Stanford University School of Medicine, Department of Psychiatry and Behavioral Science, Stanford Psychiatry Structural Neuroimaging Laboratory, 401 Quarry Road, Psychiatry Building, Room 3360, Stanford, CA 94305-5719, USA
Van Amelsvoort et al (2001) report characteristic brain changes in 10 adults with velo-cardio-facial syndrome (VCFS) and 13 matched controls. The study represents an important contribution, as it is the first quantitative structural neuroimaging investigation that focuses on affected adults. The sample includes individuals with and without schizophrenia, thereby allowing generalisation to the larger population of adults with deletion 22q11.
In common with other investigations of subjects with neurogenetic disorders, the small sample size limits statistical power for detecting neuroanatomical differences. Null results have been interpreted and have been contrasted with a finding from our study (Eliez et al, 2000), a finding that may have been misunderstood. Specifically, the authors state that their observation of no volumetric changes in the frontal lobe among adults with VCFS is in contrast to our observation of frontal lobe abnormalities in children and that this discrepancy might indicate "delayed frontal lobe maturation which is detectable as differences in total frontal volume in childhood but subsequently normalises somewhat in adulthood...". This interpretation implies that we found smaller frontal lobe volumes. While absolute volumes of the frontal lobe volumes were indeed smaller, adjusted frontal lobe sizes were in fact larger after statistically covarying for total brain volume, suggesting relative preservation of this structure. Preservation of frontal regions has been indicated in another recent study (Kates et al, 2001) reporting larger adjusted frontal lobe volumes and is potentially consistent with the voxel-based comparisons in the van Amelsvoort et al study, which found increased grey matter density in this region.
Two additional findings are of interest. The reported reduction in cerebellar volume is consistent with results of other recent studies (Eliez et al, 2000, 2001a), and the observed decrease in temporal lobe grey matter density among adults is in accordance with our finding of an inverse correlation between age and temporal lobe volume among affected children (Eliez et al, 2001b).
Collectively, findings from the aforementioned neuroimaging studies that rely on samples of differing age groups create an emerging picture of brain development in deletion 22q11 and will contribute to an increased understanding of VCFS as a genetically mediated subtype of schizophrenia.
REFERENCES
Eliez, S., Schmitt, J. E., White, C. D., et al
(2000) Children and adolescents with velocardiofacial
syndrome: a volumetric MRI study. American Journal of
Psychiatry, 157,
409-415.
Eliez, S., Schmitt, J. E., White, C. D., et al (2001a) A quantitative MRI study of posterior fossa development in velocardiofacial syndrome. Biological Psychiatry, 49, 540-546.[CrossRef][Medline]
Eliez, S., Blasey, C. M., Schmitt, E. J., et al
(2001b) Velocardiofacial syndrome: are structural
changes in the temporal and mesial temporal regions related to schizophrenia?
American Journal of Psychiatry,
158,
447-453.
Kates, W. R., Burnette, C. P., Jabs, E. W., et al (2001) Regional cortical white matter reductions in velocardiofacial syndrome: a volumetric MRI analysis. Biological Psychiatry, 49, 677-684.[CrossRef][Medline]
van Amelsvoort, T., Daly, E., Robertson, D., et al
(2001) Structural brain abnormalities associated with
deletion at chromosome 22q11. Quantitative neuroimaging study of adults with
velo-cardiofacial syndrome. British Journal of
Psychiatry, 178,
412-419.