The development of the corpus callosum in semilobar and lobar holoprosencephaly.
OBJECTIVE
The objective of this study was to determine whether and how a true corpus callosum develops in milder cases of holoprosencephaly.


METHODS
The MR scans of seven patients with holoprosencephaly and a callosum-like structure were reviewed. The anatomy of the callosum-like structure and the pericallosal anatomy were evaluated.


RESULTS
Six of the seven cases had a posterior corpus callosum. The seventh case was indeterminate because lack of myelination prevented confirmation that the callosum-like structure consisted only of white matter. In each case the posterior corpus callosum formed posterior to white matter which spanned the interhemispheric fissure beneath a layer of cortical gray matter.


CONCLUSIONS
A posterior corpus callosum can develop in holoprosencephaly because the first callosal axons use the white matter of the undivided hemispheres as a bridge to cross the interhemispheric fissure.
Rubinstein
D
D
Department of Radiology, University of Colorado Health Sciences Center, 4200 East Ninth Avenue, Campus Box A-034, Denver, CO 80262, USA.
Cajade-Law
A G
AG
Youngman
V
V
Hise
J M
JM
Baganz
M
M
D061085:Agenesis of Corpus Callosum; D002675:Child, Preschool; D003337:Corpus Callosum / Q000473:pathology; D005260:Female; D016142:Holoprosencephaly / Q000175:diagnosis / Q000473:pathology*; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D008279:Magnetic Resonance Imaging; D008297:Male