MRI shows abnormal white matter maturation in classical holoprosencephaly

Area of Science:

• Neuroimaging
• Developmental Biology
• Pediatric Neurology

Background:

• Holoprosencephaly (HPE) is a congenital brain malformation with significant variability.
• Understanding the spectrum of HPE, including its variants, is crucial for diagnosis and prognosis.
• White matter development is a key indicator of neurological maturation.

Purpose of the Study:

• To evaluate white matter maturation in patients with holoprosencephaly using MRI.
• To compare white matter development between different variants of HPE.
• To investigate potential differences in the underlying etiology of HPE subtypes based on myelination patterns.

Main Methods:

• Retrospective review of MRI scans from 47 patients diagnosed with HPE.
• Assessment of white matter maturation and myelination status.
• Categorization of patients based on HPE variant (classic HPE and middle interhemispheric variant).

Main Results:

• Delayed white matter maturation was observed in 25 out of 47 (53%) HPE patients.
• Among patients with classic HPE aged 12 months or younger, 24 out of 29 (83%) showed delayed myelination.
• All six patients with the middle interhemispheric (MIH) variant of HPE exhibited normal myelination, irrespective of age.

Conclusions:

• The findings suggest distinct developmental trajectories for different HPE variants.
• Delayed myelination is common in classic HPE, especially in infants.
• Normal myelination in the MIH variant supports the hypothesis of different pathogenetic mechanisms for HPE subtypes.