Dysgenesis of the deep venous system as a diagnostic criterion for holoprosencephaly

Dual white matter pathology in fetal holoprosencephaly featuring concurrent malformative and destructive features: A case series

Holoprosencephaly (HPE) is a classic brain malformation involving defective forebrain induction and patterning. Cases of HPE bearing white matter abnormalities have not been well documented, with only rare cases exhibiting hypoxic-ischemic damage. However, neuroradiologic studies of HPE using diffusion tensor imaging have suggested the presence of white matter architectural disarray. Described in this case series are the clinicopathologic features of 8 fetuses with HPE who underwent autopsy at BC Children's Hospital. All 8 cases exhibited subacute to chronic, periventricular leukomalacia (PVL)-like white matter pathology, with 7 of 8 cases also demonstrating aberrant white matter tracts, one of which manifested as a discreet bundle crossing the midline within the ventral aspects of the fused deep gray nuclei. In 6 of these 7 cases, the PVL-like pathology resided within this aberrant white matter tract. Original workup, alongside an additional HPE-focused next-generation sequencing panel identified a likely etiologic cause for the HPE in 4 cases, with an additional 2 cases exhibiting a variant of unknown significance in genes previously suggested to be involved in HPE. Despite our in-depth clinicopathologic and molecular review, no unifying etiology was definitively identified among our series of fetal HPE bearing this unusual pattern of white matter pathology.

A new clue to the prenatal diagnosis of lobar holoprosencephaly: the abnormal pathway of the anterior cerebral artery crawling under the skull

We report a case of a 24-week-old fetus with cerebral anomalies suggestive of lobar holoprosencephaly including an unusual course of the anterior cerebral artery on Doppler examination. This abnormal trajectory of the anterior cerebral artery in holoprosencephalic brains has been described by pathologists, neurosurgeons and radiologists but our case indicates that this finding may be a useful adjunct to confirm such a difficult diagnosis prenatally.

Holoprosencephaly in neurosurgical practice

The clinical, angiographic, and pneumoencephalographic features of seven cases with holoprosencephaly are reported. Three of the alobar type in this series revealed the facial dysmorphia characteristic of the anomaly. In the other four cases (one alobar, one semilobar, and two lobar), such facial anomaly was absent, and the diagnosis was achieved only after contrast studies. An azygous anterior cerebral artery running over the cerebral surface due to a defective interhemispheric fissure is pathognomonic for alobar and semilobar holoprosencephaly. Dysgenesis of the deep venous system was found in alobar, semilobar, and lobar holoprosencephaly, a finding helpful in diagnosis, especially of the lobar type. Air study and computerized tomography scan revealed incomplete separation of the ventricular system. The basic nature of holoprosencephalization and its differentiation from non-holoprosencephalic malformation are discussed. Six of the seven patients reported had hydrocephalus.