Presentation
Child patient presented with hypotonia and delayed milestones/developmental delay.
Patient Data
The lateral ventricles appear dysmorphic with absent septum pellucidum.
There is bridging heterotopic grey matter between the cerebral hemispheres at the level of the body of the corpus callosum, this bridging grey matter seems completely replacing the body of the corpus callosum. Preserved rostrum, genu and splenium of the corpus callosum.
The falx cerebri appears almost absent
The anterior cerebral artery is azygous.
Left cerebellar hypoplasia is also noted with surrounding enlarged CSF spaces.
Abnormal vertical orientation of both sylvian fissures.
Widened anterior interhemispheric fissure.
Features are consistent with the middle interhemispheric variant of holoprosencephaly (syntelencephaly)
Case Discussion
As in this case cerebellar hypoplasia and azygos anterior cerebral artery are well known associations, other associations: Chiari I malformation, dorsal cyst of holoprosencephaly, and polymicrogyria.
Genetic assessment may be indicated to exclude mutations such as ZIC2 mutation at 13q32 (which is seen in 5-6% of cases).