Dandy-Walker malformation: prenatal diagnosis and prognosis

Area of Science:

• Neuroscience
• Developmental Biology
• Medical Imaging

Background:

• Dandy-Walker malformation (DWM) prognosis is challenging due to diverse presentations and overlapping imaging features.
• Accurate DWM diagnosis requires high-quality MRI, including sagittal views of the vermis and T2-weighted sequences.
• This study defines DWM based on specific posterior fossa and vermis anatomical criteria.

Purpose of the Study:

• To investigate the correlation between cerebellar vermis anatomy in Dandy-Walker malformation (DWM) and neurodevelopmental outcomes.
• To differentiate DWM subtypes based on vermis morphology and associated brain anomalies.
• To identify prognostic indicators for clinical and intellectual outcomes in DWM patients.

Main Methods:

• Retrospective review of 26 DWM patients' medical records, including MRI and neuro-psychological assessments.
• Exclusion of syndromic DWMs and Dandy-Walker variants.
• Blinded MRI review focusing on vermis anatomy, brain malformations, and associated systemic anomalies.

Main Results:

• Two distinct vermis morphologies were identified in DWM patients.
• Group 1 (n=21): Vermis with normal fissures/lobes, typically isolated, associated with normal neurodevelopment (except for 2 cases with other causes of delay).
• Group 2 (n=5): Highly dysplastic vermis, associated with major brain anomalies (e.g., corpus callosum agenesis), invariably leading to significant intellectual disability.

Conclusions:

• DWM can be categorized into two distinct types based on vermis anatomy.
• The most common type, with an isolated, partially agenetic vermis, is compatible with normal development.
• A less common type, featuring a severely dysplastic vermis and associated brain malformations, is consistently linked to mental retardation.